Cutting – By tool inside hollow work – With manually actuated means to position or facilitate...
Reexamination Certificate
2001-07-18
2003-08-05
Sewell, Paul T. (Department: 3711)
Cutting
By tool inside hollow work
With manually actuated means to position or facilitate...
C083S054000
Reexamination Certificate
active
06601492
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the art of punching openings in a workpiece and particularly to press devices for punching elongated, hollow profiled bars, mostly aluminum extruded bars, as used in the building industry for the construction of door and window frames.
BACKGROUND OF THE INVENTION
In order to better evaluate the contribution to the art of the present invention reference shall be made to
FIGS. 1
a-
1
d,
schematically illustrating the traditional, state of the art technique of punching extruded bars. Hence, in
FIG. 1
a
there is shown a punching press device generally denoted
10
of any known construction, namely usually provided with a pneumatic cylinder and piston unit
12
, and male punch
14
.
To base plate
16
of the device
10
there is connected a generally L-shaped extension bar
18
to which a mandrel rod
20
is fixedly connected (by bolts
22
). The mandrel rod carries at its free end female punch die (“matrix”)
24
with counter-opening
25
configured to back-up extruded profile
26
during the punching operation.
The mandrel rod
20
is provided with a fixable stop bracket
28
for setting the distance of the punched opening from the end of processed profiled bar
26
.
It will be noted that the mandrel rod
20
is somewhat flexible and normally, when not in operation, it extends at a certain angle relative to the horizontal slanting in the direction of the punching press
10
. However, when the extruded profiled bar
26
is dressed over the matrix
24
(
FIG. 1
b
), the rod
20
becomes precisely aligned, namely slightly raised by the lower wall width W
1
of the bar
26
. This will ensure that the male punch
14
and the female back-up die are in exact vertical alignment with respect to each other to ensure a clean cut of the opening.
As evident from
FIG. 1
c,
the horizontal alignment or location of the matrix
24
is ensured by a roller or the equivalent device
30
the location thereof again takes into account the side wall width W
2
of the bar
26
.
Now, these principles of construction and working process are common to existing punching presses as known now for decades.
These devices, however, suffer from numerous drawbacks. First, it is generally inconvenient and time-consuming to insert the sometimes quite long profiled bars
26
into the operative position of
FIG. 1
b,
bearing in mind that only small tolerances must be left between the inner cross-section of the bar
26
and the outer shape of the female matrix
24
.
Secondly, it is inconvenient to remove the stamped wall pieces of the processed bars from the opening
25
following one or several punching cycles.
Thirdly, due to the unaligned or tilted initial position of the mandrel rod
20
, when not in use, it is recommended always to keep a piece of a profiled bar
26
′ over the matrix
24
—see
FIG. 1
d.
This precaution measure is taken to avoid damage to the male punch
14
and/or the matrix
24
if, unintentionally, the press
10
is operated while being in the position of
FIG. 1
a,
namely when the matrix counter opening
25
is not in exact vertical register with the opening of the male punch
14
.
Lastly, should the back-up opening (
25
) be located off-centrally (as exemplified in
FIG. 1
c
), and it is required to have another opening be formed exactly oppositely, at the other wall of the bar (
26
), it is necessary to employ a separate, additional punching device (press and matrix).
A prior art device of the above mentioned kind is disclosed in Document U.S. Pat. No. 3,489,045 relating to a tube punching device for punching openings in profiled bars comprising a male punch and a female punching matrix for backing the bar during the punching operation wherein the punching matrix is attached to an elongate mandrel rod, the mounting constituted by the punching matrix and elongated mandrel rod being permanently mounted to a supporting frame and allowed only to carry out an up and down movement and a limited degree of movement from left to right. Therefore the mounting unit is not removable in operation from the supporting frame.
These and additional drawbacks of the existing punching press devices and method of operation are designed to be overcome by the contribution of the present invention.
It is thus the general object of the present invention to substitute the fixed mandrel rod and matrix structure by a portable or non-stationary mandrel bar.
It is a further object of the invention to provide punch press devices, utilizing the concept of non-stationary mandrel rod, for the application of punched openings at two or three walls of a processed extruded bar simultaneously.
SUMMARY OF THE INVENTION
Thus, there is provided according to a first aspect of the present invention a punching press device for punching openings in profiled bars comprising a male punch and a female punching matrix for backing the bar during the punching operation characterized in that the punching matrix is attached to an elongated rod removable from the punch device, means being provided for releasably placing the rod in a position suitable for punching an opening in the profiled bar by the male punch against the female punching matrix.
According to another aspect of the present invention there is provided a method of punching openings in profiled bars by punching press device comprising a male punch die and a female punching matrix, the method comprising the steps of mounting the female punching matrix to an elongated rod, inserting the matrix and a portion of the rod into the profiled bar; and placing the assembly of matrix and rod in a position suitable for punching the opening by the male punch.
The profiled bars may be hollow or non-hollow, as the case may be.
REFERENCES:
patent: 1503551 (1924-08-01), Nice
patent: 3489045 (1970-01-01), Ray
patent: 4744276 (1988-05-01), Duce
patent: 5347899 (1994-09-01), Schultz et al.
patent: 2024690 (1980-01-01), None
Chambers M.
Ostrolenk Faber Gerb & Soffen, LLP
Sewell Paul T.
Shoham Machines and Dies Ltd.
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