Machine tools abstract
A pivotable stop for machine tools, in particular panel saws, having
a striker bar, on which a first stop flap is mounted in a longitudinally
displaceable but fixed manner, and is connected to a measurement
and display unit which determines and displays the relative position
of the stop flap to the striker bar, and in which a rod can telescopically
be extended and retracted, which bears a second stop flap at its
free end, characterized in that a coupling placed at the measurement
and display unit detachably connects the rod to the measurement
and display unit.
Machine tools claims
We claim:
1. A crosscut fence for machine tools, in particular panel saws,
having a guide bar, on which a first pivotable throwover stop is
mounted in a longitudinally displaceable but fixed manner, and is
connected to a measurement and display unit which determines and
displays the relative position of the pivotable throwover stop to
the guide bar, and in which a rod can be telescopically extended
and retracted, which bears a second pivotable throwover stop at
its free end, characterized in that a coupling placed at the measurement
and display unit detachably connects the rod to the measurement
and display unit, and in that the coupling consists of a stop bolt
which can move transversely to the longitudinal axis of the rod,
and which can be introduced into a bore in the rod.
2. A crosscut fence for machine tools, in particular panel saws,
having a guide bar, on which a first pivotable throwover stop is
mounted in a longitudinally displaceable but fixed manner, and is
connected to a measurement and display unit which determines and
displays the relative position of the pivotable throwover stop to
the guide bar, and in which a rod can be telescopically extended
and retracted, which bears a second pivotable throwover stop at
its free end, characterized in that a coupling placed at the measurement
and display unit detachably connects the rod to the measurement
and display unit, and in that when the coupling is engaged the measuring
range of the measurement and display unit can be switched to the
second pivotable throwover stop.
3. A crosscut fence for machine tools, in particular panel saws,
having a guide bar, on which a first pivotable throwover stop is
mounted in a longitudinally displaceable but fixed manner, and is
connected to a measurement and display unit which determines and
displays the relative position of the pivotable throwover stop to
the guide bar, and in which a rod can be telescopically extended
and retracted, which bears a second pivotable throwover stop at
its free end, characterized in that a coupling placed at the measurement
and display unit detachably connects the rod to the measurement
and display unit, and in that the coupling consists of a stop bolt
which can move transversely to the longitudinal axis of the rod,
and which can be introduced into a bore in the rod, and in that
when the coupling is engaged the measuring range of the measurement
and display unit can be switched to the second pivotable throwover
stop.
4. A cross cut fence according to one of claims 1 2 or 3 characterized
in that a third pivotable throwover stop is guided in a longitudinally
displaceable manner on the guide bar and can be stopped in relation
thereto and can also be coupled to the measurement and display unit.
5. A guide fence for machine tools provided with a plurality of
selectively useable and independently adjustable stops and with
measurement and display means associated with said stops for indicating
the position thereof, wherein
(a) a single measurement and display unit is provided for selectively
indicating the position of a selected one of said plurality of stops,
(b) said measurement and display unit being normally mechanically
coupled with a first one of said stops and being movable therewith
for indicating the adjusted position thereof,
(c) means for mechanically coupling a second one of said stops
to said to said measurement and display unit for movement therewith,
(d) said first and second stops, when coupled with said measurement
and display unit, being positioned at known fixed distances therefrom
whereby the positions of said first and second stops can be determined
from the position of said measurement and display unit.
6. A guide fence according to claim 5 wherein
(a) said stops are pivotally mounted on said guide fence for movement
between active and retracted positions, and
(b) means are provided for adjusting the measuring range of said
measurement and display unit, in response to the pivoting of a selected
stop to an active position, to correspond to the range of said selected
stop.
Machine tools description
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a crosscut fence for machine tools, in
particular panel saws, having a guide bar, on which a first pivotable
throwover stop or workstop abutment is mounted in a longitudinally
displaceable but fixed manner, and is connected to a measurement
and display unit which determines and displays the relative position
of the pivotable throwover stop to the guide bar, and in which a
rod can be telescopically extended and retracted and which at its
free end bears a second pivotable throwover stop.
So that it is possible to manufacture dimensionally accurate workpieces
by means of machine tools, the blanks to be machined are positioned
by means of so-called stops on the machine, after said stops have
been adjusted according to the desired dimensions of the workpiece.
Panel saws are primarily used to cut to size panels, boards and
battens from wood or plastic, for example by means of angular cuts,
parallel cuts and cuts along the grain. In this case a so-called
crosscut fence or left-hand stop is used to adjust the desired material
dimensions, which essentially consists of a guide bar mounted on
the cross slide and at least one pivotable throwover stop, against
which the workpiece abuts during cutting to size.
As is known, mechanical or electronic measurement systems are used
to adjust and indicate the distance from a pivotable throwover stop
to the cutting tool. An electronic measurement system may consist
of, for example, a magnetically coded measuring tape mounted along
the guide bar, a sensor which is connected to a pivotable throwover
stop and scans the measuring tape without contact and also a switching
arrangement processing the readings recorded by the sensor and a
display unit optically representing the distance measurement (German
Utility Model 91 14 150.8).
The utilisation of several fold-down pivotal throwover stops disposed
on a guide bar is also known for different measurement ranges. In
this case a first displaceable pivotable throwover stop can be connected
to a sensor recording its relative position and a second pivotable
throwover stop can be securely connected to a telescopic rod which
is mounted in a telescopic and displaceable manner inside the guide
bar. With such a stop, to determine the distance of the two pivotable
throwover stop with an electronic system, a measuring tape on the
telescopic rod and the guide bar and also two sensors are required,
as a result of which the manufacturing costs are relatively high
(German Utility Model 92 07 797.8).
The object of the invention is to make available a crosscut fence
which can be manufactured at a favourable cost, with which the relative
positions of several pivotable throwover stop can be simply determined
and adjusted in relation to the operation in various measuring ranges
by means of a single measurement and display unit and a measuring
tape.
The object is achieved by a crosscut fence of the above-mentioned
type in that a coupling placed at the measurement and display unit
detachably connects the rod with the measurement and display unit.
By such a mechanical coupling the relative positions of two pivotable
throwover stop can be determined and also adjusted by simple means
and in particular independently of one another with only one sensor
and a magnetically coded measuring tape.
The coupling advantageously consists of a stop bolt, which can
move transversally to the longitudinal axis of the rod and which
can be introduced into a bore in the rod, as a result of which a
coupling is produced in a simple manner, which, for example, can
be manually operated with a knob.
With the engagement of the coupling, the measuring range of the
measurement and display unit is advantageously switched over to
the second pivotable throwover stop, as a result of which this can
be quickly adjusted to the desired distance, in particular with
a frequent change-over between the measuring ranges. The change-over
may be performed, for example, by an electrical switch on the coupling.
An embodiment in which the connection between the first pivotable
throwover stop and the measurement and display unit is detachable
is also advantageous, so that, after the first pivotable throwover
stop has been fixed in the desired position, the adjustment of the
second or a further pivotable throwover stop can be performed by
coupling the measurement and display unit, without the first stop,
which has already been fixed, having to be moved again.
An advantageous refinement lies in that the rod with the second
stop flap can be stopped in relation to the striker bar so that
the second pivotable throwover stop can be fixed in the desired
position on the guide bar by a clamping device which is easy to
operate.
With a pivotable stop, in which a third pivotable throwover stop
is guided in a longitudinally displaceable manner on the guide bar
and can be stopped in relation thereto and can also be coupled to
the measurement and display unit, three distance measurements of
the pivotable throwover stop from the tool can be adjusted in different
measuring ranges and be activated by folding down the pivotable
throwover stops. If the coupling for the third pivotable throwover
stop consists of a drag stop which only responds to pressure, with
the abutment of which the third pivotable throwover stop has a defined
distance from the first pivotable throwover stop the adjustment
of the third pivotable throwover stop can be achieved in a particularly
simple manner and as a result of the fact that the drag stop is
adjustable.
A fast exchange of the measuring range is possible if the pivotable
throwover stops can be swivelled in a known manner out of an active
position into an inoperative position and their swivelling changes
the measuring range of the measurement and display unit, for example
by electromagnetic switches, and if, when the drag stop is adjacent,
the measuring range of the measurement and display unit is switched
over to the third pivotable throwover stop.
The present invention is described below for the sake of example
with reference to the attached drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective representation of a preferred embodiment
of a crosscut fence having three pivotable throwover stops and
FIG. 2 shows an embodiment according to FIG. 1 in which the second
pivotable throwover stop is represented in an extended position
and
FIG. 3 shows an adjustable drag stop, a coupling having a stop
bolt and also a part of the measurement and display unit.
DETAILED DESCRIPTION OF THE INVENTION
The crosscut fence 1 represented in FIG. 1 essentially comprises
a guide bar 2 a first pivotable throwover stop 4 a second pivotable
throwover stop 6 a third pivotable throwover stop 8 a measurement
and display unit 10 and a rod 12 guided inside the guide bar 2 (not
represented in FIG. 1 but see FIG. 2), which at its free end bears
the second pivotable throwover stop 6. The crosscut fence 1 is slipped
onto a cross slide (not represented) of a machine tool, in particular
panel saw, and is attached by appropriate devices, for example star
grip nuts or control levers. The crosscut fence 1 can be moved by
means of the cross slide relative to the driven tool and if necessary
can be swivellably mounted to perform mitre cuts.
The pivotable throwover stops 4 and 8 are swivellably attached
in a known manner to sliders 14 and 16 which are mounted in a longitudinally
displaceable manner on the guide bar 2 and the pivotable throwover
stop 6 is also attached in a swivelling manner to a rod carrier
18 which is in turn securely connected to the end of the rod 12
which can be telescopically extended and retracted inside the guide
bar 2 which is constructed as a hollow section. Because of the
swivelling attachment to the sliders 14 and 16 and respectively
to the rod carrier 18 the pivotable throwover stops 4 8 and 6
can be swivelled out of an active position into an inoperative position,
for example by being folded down manually. The pivotable throwover
stops 4 8 and 6 can be immobilised in a continuously adjustable
manner in a desired position in relation to the guide bar 2 by means
of clamping devices 22 24 and 26 provided on the sliders 14 and
16 and respectively on the rod carrier 18. The immobilisation facility
of the rod with the second pivotable throwover stop 6 can also be
achieved in that the clamping device 26 is provided at a position
on the guide bar 2 other than that represented, for example close
to the measurement and display unit 10. By the clamping devices
22 24 and 26 which are manually operated by rotating star grip
nuts or control levers, the pivotable throwover stops are fixed
by a frictional connection.
In FIG. 2 the second pivotable throwover stop 6 is represented
in an extended position, in which the telescopically extensible
rod 12 can be clearly seen.
The measurement and display unit 10 which is mounted in a closed
housing, is in this exemplified embodiment attached to the slider
14 and thus connected to the first pivotable throwover stop 4 and
can be moved jointly therewith on the guide bar 2. The measurement
and display unit 10 comprises a sensor (not represented), a source
of electricity, a control and display panel 28 a digital display
30 a keyboard 32 and also a main switch 34. The sensor scans without
contact a magnetically coded measuring tape 36 mounted along the
guide bar 2 so that the respective relative position of the sensor,
and thus of the measurement and display unit 10 and consequently
of the first pivotable throwover stop 4 can be determined and indicated
by a switching and processor unit also mounted inside the measurement
and display unit.
At one end of the slider 14 adjacent to the measurement and display
unit 10 is provided a coupling 38 connected therewith, which detachably
connects the rod 12 with the measurement and display unit 10 by
it being possible to insert a stop bolt 46 which is mounted in
an axially displaceable manner and can be moved manually (cf. FIG.
3), into a bore (not represented) disposed transversally to the
longitudinal axis of the rod 12 and to remove it therefrom, so that
a form-fit connection can be produced. Because it is possible to
couple the second pivotable throwover stop 6 connected to the rod
to the measurement and display unit 10 by means of said unit its
relative position can be determined when the distance of the bore
from the pivotable throwover stop 6 is precisely known. Consequently
the relative positions of the pivotable throwover stops 4 and 6
in relation to the guide bar 2 can be determined with the measurement
and display unit 10 in cooperation with the measuring tape 36. At
the coupling 38 there is additionally provided a switch (not represented),
by which, when the coupling is engaged, the measuring range of the
measurement and display unit 10 is automatically switched to the
second pivotable throwover stop 6 so that the distance of the pivotable
throwover stop 6 from the tool (not represented) is directly indicated
on the digital display 30.
Between the first pivotable throwover stop 4 and the measurement
and display unit 10 there can either be a permanent connection,
or the connection between these two components can be detachable,
for example by a mechanical coupling or a quick-release screw connection,
so that the measurement and display unit 10 can be displaced independently
of the pivotable throwover stop 4 with the engagement of the coupling
38 together with the second pivotable throwover stop 6 to adjust
the second pivotable throwover stop 6 while the first pivotable
throwover stop 4 remains in the previously adjusted relative position.
The third pivotable throwover stop 8 which can also be displaced
on the guide bar 2 can be coupled by means of a so-called drag
stop 40 to the measurement and display unit 10. In this exemplified
embodiment the drag stop 40 is also disposed on one end of the slider
14 next to the measurement and display unit 10 at a defined distance
to both the first pivotable throwover stop 4 and also to the sensor
of the measurement and display unit 10 so that when the drag stop
40 touches the slider 16 and thus the third pivotable throwover
stop 8 its relative position is precisely determined. When a drag
pivotable throwover stop is used, the stop 8 can only be displaced
in one direction to the guide bar 2 whereas with the use of a multi-action
coupling which is also possible, the third pivotable throwover stop
8 could be displaced in both directions on the guide bar. The drag
stop 40 can be precisely adjusted by means of an adjustment screw
42 and a check nut 43.
In FIG. 3 are represented the drag stop 40 the coupling 38 and
a part of the measurement and display unit 10. The drag stop 40
illustrated in the partial section representation, which is disposed
at one end of the slider 14 can be adjusted by means of the adjustment
screw 42 which is in engagement with a thread cut in the slider
14 and the adjustment screw 42 can be fixed with the check nut
43. In addition the stop bolt 46 of the coupling 38 is represented,
which can be axially displaced by actuating a knob 48.
By swivelling the pivotable throwover stops 4 8 and 6 from their
active position into the inoperative position, switches (not represented)
are actuated, by which the measuring range of the measurement and
display unit 10 is changed. On the drag stop 40 is also provided
a switch (not represented), by which the measuring range of the
measurement and display unit 10 is switched over to the third pivotable
throwover stop 8 if the drag stop 40 is switched to the pivotable
throwover stop 8.
In this embodiment the first stop flap 4 has a measuring range
of from 140 to 1450 mm, the pivotable throwover stop 8 has a measuring
range from roughly 440 to 1450 mm and pivotable throwover stop 6
has a measuring range from roughly 1450 to 2750 mm. By means of
the keys 32 the respective position of the pivotable throwover stop
can be ascertained by simply switching over. On the slider 14 of
the first pivotable throwover stop 4 there is an adjustment screw
44 for fine adjustment. |