APPARATUS FOR STAMPING PROFILED BARS
BACKGROUND OF THE INVENTION
The present invention generally relates to punching apparatus, and
more particularly to apparatus for stamping marginal pieces or the like plates out of generally U-shaped profiled bars.
The invention particularly concerns stamping of profiled bars used in the industry of constructing curtain walls or outer framework structure around
buildings for supporting external protective glass panes, as now dominant in modern office buildings all over the world.
A typical curtain walls bar B (see Fig. 1 ) generally comprises a web portion denoted W, a pair of up-right legs _L, and a central up-right rib R.
These bars have to be processed in such a way that a plurality of cut-outs C
have to be removed at predertemined distances, usually at both sides, but
sometimes only at one side thereof. The length of the processed bars is
considerably large, usually about 5 to 8 meters.
Punching apparatus for this purpose has already been designed.
Hence, in Fig. 2 there is schematically shown a prior art apparatus 10 which
essentially comprises a supporting guide rail 12 on which profiled bar 14 is
supported during punching, as well as for sliding it along the predetermined
distances between successive punching operations.
The profiled bar 14 is pressed against the guide rail 12 during the
punching operation by a pneumatic cylinder unit 16.
A pair of stamping dies 17 and 18 are provided, operable in the outward direction by pneumatic cylinder units denoted 20 and 22, respectively. As
further schematically shown, the stamping is performed against matrixes
24, 26 as customary in the art. A pneumatic control panel is provided (not
shown) whereby the operator can actuate either or both of the pneumatic
cylinders 20 and 22, as required for the particular job at hand.
These prior art apparatus, although almost exclusively used around
the world are inefficient or otherwise disadvantageous in any or all of the
following respects: First - the need for a pair of cylinders and auxiliary controls is cumbersome, expensive and space-consuming; secondly - due to the particular construction of the apparatus, the maneuverability of the
processed profiled bars 14 is inconvenient; and thirdly, due to the inherent
structure, the vision field of the operator is partly obstructed, presenting
certain difficulty in placing bars at the exact position for punching the cut-out
pieces C at the precise selected location.
It is thus the general object of the present invention to provide an apparatus that will be less expensive and more convenient to operate.
It is a further object of the invention to provide an apparatus employing
only one pneumatic (or hydraulic) piston for operating one, the other, or both
of the stamping dies.
It is a still further object of the invention to obtain an amplification of the
piston force, thereby saving on measurements and/or pressure needed for
their effective operation.
SUMMARY OF THE INVENTION
Thus provided according to the present invention is a press
punching apparatus particularly for stamping marginal sections off U-shaped profiled elongated bars having a web and two upright legs, comprising
support means for firmly supporting the bar by its web during the stamping
operation, at least one stamping die located within the bar opposite the leg
portion which is to be stamped, slidable mounting means for the stamping
die, enabling the displacement of the die for effecting the stamping operation
of the section of the respective bar leg, means for the displacement of the
stamping die, which comprise a cylinder and piston unit operating piston rod,
wedge lever means operatively associated with the stamping means, and
means for coupling the piston rod to the wedge lever means so that by
operating the cylinder and piston unit, the stamping die becomes displaced to complete the stamping of a respective section of the bar leg.
Preferably the apparatus will comprise an additional stamping die located
within the bar opposite to the other leg portion, and with associated displacing means operable by the cylinder and piston unit.
The wedge lever means preferably comprise a block operatively
connected to the piston rod, to reciprocate in a direction normal to that of
stamping die, a slot formed in the block, extending at an angle relatively to
the said direction, and a bolt pin selectively insertable through the slot to — establish the transforming of the piston rod reciprocating movement to
movement of the stamping die.
BRIEF DESCRIPTION OF THE DRAWINGS
These and additional features and advantages of the present invention
will be more clearly understood in the light of the following description of a preferred embodiment thereof, given by way of example only, with reference
to the accompanying drawings, wherein-
Fig. 1 is a three-dimensional view of a typical profiled curtain wall
construction bar;
Fig. 2 is a schematic representation of a prior art punching apparatus;
Figs. 3 is a schematic representation of a punching apparatus
according to principles of the present invention in a non-operative
position;
Fig. 4 is a section taken along line IV-IV of Fig. 3;
Fig. 5 is a view taken along line V-V of Fig. 3; and
Fig. 6 shows the apparatus of Fig. 3 in its operating, cutting position.
DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENTS
Referring to Fig. 3 of the attached drawings it will be noted that, similarly to the prior art apparatus of Fig. 2, a guide rail 30 is provided,
configured to support the processed bar_B, which is also clamped during
punching by pneumatic cylinder and piston unit 32; so are conventionally
provided stamping matrixes 34 and 36 associated with stamping dies 38 and 40, respectively.
Rather then connecting the stamping dies directly to pneumatic pistons as in the prior art apparatus, the following arrangement is applied. The
stamping dies 38 and 40 are respectively mounted to carriage members 42,
44 which are suitably supported for reciprocating sliding movement by housings 46 and 48 (one being shown in cross-section in Fig. 4).
Since the construction is symmetrical, reference shall be made to the
right-hand side of the apparatus only, being understood that the left-hand
side is a mirror-image thereof.
A driving mechanism generally designated 50 is provided, comprising
push-pull rod 52, reciprocally movable by being coupled by bracket 54 to
piston rod 56 of fixedly supported pneumatic cylinder 58. The rod 52 is
connected to a cam block 60, preferably via screw-threaded adjusting
tie-rod 52a.
The cam block 60 is slidable vertically within the housing 46, and is formed with an inclined slot 62. The block is selectively coupled to the
carriage member 42 by a pin bolt 64 (legs 42a and 42b). The inclined slot
62 thus constitute wedge-lever means, converting the vertical movement of ~
the block 60 into a horizontal movement of the carriage member 42.
It will be readily understood in the light of the foregoing description that the operation of the apparatus proceeds as follows:-
Once processed bar_B is placed on the support 30 and press-clamped by the piston 32, at the correct location ready for operation, the piston 58
receives a command to push the piston rod 56 down. Hence, (see Fig. 6) push-pull rod 52 will be pulled down, bringing about a movement of the
carriage member 42 to the right due to the movement of the pin bolt 64
along the slot 62. It will be also appreciated that a certain amplification
factor of the piston force is achieved in proportion to the inclination angle of
the slot 62 (less a certain friction force which is inevitably generated).
The stamping die 38 will thus move to the right thereby performing the
stamping operation.
The same will apply to the left-hand stamping die 40, however in the
opposite direction.
Should a punching operation be completed only at one (the left) side of
the bar B, the pin bolt 64 will be pulled out of slot 62 (using handle 64a as
shown in phantom lines in Fig. 4) thereby neutralizing the movement of the
respective carriage 42 and no punching operation will be performed.
It should now be clear that the provision of the screw-threaded
adjusting tie-rod 52a allows to achieve fine adjustments of cutting depth,
dominated by considerations such as the wall thickness of the processed
bar B.
It has thus been established that the novel apparatus design is
superior to the prior art apparatus in the respects hereinabove specified.
While the above description contains many specificities, these should
not be construed as limitations on the scope of the invention, but rather as
exemplification of the preferred embodiment. Those skilled in the art will
envision other possible variations that are within its scope. Accordingly, the
scope of the invention should be determined not by the embodiment
illustrated, but by the appended claims and their legal equivalents.