U.S. patent application number 09/824573 was filed with the patent office on 2001-10-25 for pressing tool and pressing process.
This patent application is currently assigned to Novartec AG Liechtenstein. Invention is credited to Goop, Hans-Joerg.
Application Number | 20010032490 09/824573 |
Document ID | / |
Family ID | 7637568 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010032490 |
Kind Code |
A1 |
Goop, Hans-Joerg |
October 25, 2001 |
Pressing tool and pressing process
Abstract
A pressing tool for tightly pressing sleeve-like fittings (32a)
includes a hydraulic cylinder device having a fork-like connecting
part (7) and a drive motor. A pressing jaw (51) with a fastening
pin (50) is fastened in the fork-like connecting part (7). A piston
of the hydraulic cylinder device, which piston is connected to a
piston rod (6), is moved out of the starting position in the
cylinder by the drive motor. As a result, the piston rod (6) is
extended from the cylinder. As a result of the movement of the
piston rod (6), the cheek plates (51a, 51b) of the pressing jaw
(51) are moved apart in the region of actuation surfaces (8a, 8b)
of the cheek plates (51a, 51b) in order to press the cheek plates
(51a, 51b) together in the region of the fittings (32a) to be
pressed. In order to carry out a pressing process (44) safely, the
pressing tool has, in the region of the fork-like connecting part
(7), a presence sensor (52) which checks for the presence of the
pressing jaw (51) and, in the case of an absent or incorrectly
fastened pressing jaw (51), triggers a warning signal (45a) and,
after a delay, switches off the pressing tool if a properly
inserted pressing jaw (51) is still not present.
Inventors: |
Goop, Hans-Joerg;
(Schellenberg, LI) |
Correspondence
Address: |
ROTHWELL, FIGG, ERNST & MANBECK, P.C.
555 13TH STREET, N.W.
SUITE 701, EAST TOWER
WASHINGTON
DC
20004
US
|
Assignee: |
Novartec AG Liechtenstein
|
Family ID: |
7637568 |
Appl. No.: |
09/824573 |
Filed: |
April 3, 2001 |
Current U.S.
Class: |
72/416 |
Current CPC
Class: |
B25B 27/10 20130101 |
Class at
Publication: |
72/416 |
International
Class: |
B21D 037/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2000 |
DE |
100 16 752.7 |
Claims
1. Pressing tool for tightly pressing sleeve-like fittings (32a)
onto two pipe ends for the purpose of connecting the two pipes,
comprising a hydraulic cylinder device with a fork-like connecting
part (7), a pressing jaw (51) which can be interchangeably fastened
in this connecting part (7) by means of a fastening pin (50), and a
drive motor for actuating a piston rod (6) as an actuating member
for moving at least one cheek plate (51a, 51b), characterized in
that a presence sensor (52) for the pressing jaw (51) is provided,
which delivers a signal by means of which, in the event of an
absent or incorrectly inserted pressing jaw (51), the initiation of
a pressing process (44) can be prevented or an initiated pressing
process (44) can be terminated.
2. Pressing tool according to claim 1, characterized in that the
presence sensor (52) is one which measures without contact,
preferably one which measures inductively, and makes it possible to
detect the presence of the pressing jaw (51).
3. Process using a pressing tool according to claim 1, the clamping
movement of at least one cheek plate (51a, 51b) being permitted via
the piston rod (6) and a transmission device, characterized in
that, after an initialization step (42), in which the self-test,
start test and/or service test are carried out, a pressing jaw
presence check (45) is carried out in a repeatable second step,
before a pressing process (44) is made triggerable, and, with an
absent or incorrectly inserted pressing jaw (51), a warning signal
(45a) is output and--optionally after a repetition of the pressing
jaw presence check (45)--the pressing process is not initiated or
the initiated pressing process (44) is switched off after a delay
if the pressing jaw (51) still has not been correctly inserted at
this time.
4. Pressing process for tightly pressing sleeve-like fittings
(32a), using a pressing tool according to claim 1, the piston rod
(6) actuating the clamping movement of at least one cheek plate
(51a, 51b) via a transmission device, characterized in that, after
an initialization step (42), in which the self-test, start test and
service test are carried out, a pressing jaw presence check (45) is
carried out in a repeatable second step, before a pressing process
(44) is made triggerable, and, in the case of a correctly inserted
pressing jaw (51), an allocation check (46) is carried out after a
short delay in order to assign a piston position range value to the
inserted pressing jaw (51), and a locking check (47) is carried out
as a further checking step before enabling the triggerability of a
pressing process (44), in order to trigger at least a warning
signal (47a) if a fastening pin (50) has not been secured, and then
to initiate the pressing process (44).
5. Process according to claim 3, characterized in that the pressing
jaw presence check (45) detects an inserted pressing jaw (51) in a
non-contact, in particular inductive, measuring step and that the
locking check (47) preferably with a magnetic field measurement by
means of a Hall sensor--detects the fastening pin (50) in its
secured position.
6. Process according to claim 3, characterized in that, if the
fastening pin (50) is not secured, the continuation of the pressing
process (44) is postponed for a certain time, optionally after a
repetition of the locking check step (47), if the fastening pin
(50) still has not been properly locked at this time.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field Of the Invention
[0002] The invention relates to a pressing tool and to a pressing
process.
[0003] 2. Description of the Background Art
[0004] Pressing tools for tightly pressing sleeve-like fittings
onto pipe ends must ensure that the pressing jaws always tightly
press the fitting correctly. For the conventional fitting
diameters, corresponding pressing jaws can be inserted in each case
into the pressing tool. Because large forces are required for tight
pressing, a hydraulic cylinder is used for actuating a pressing jaw
in various known pressing tools. U.S. Pat. No. 5,125,324 discloses
embodiments in which an electric motor drives a hydraulic pump. The
pressurized liquid is fed into a hydraulic cylinder for actuating a
piston which actuates the pressing jaw. By arranging the pump with
electric motor directly on the hydraulic cylinder device, a compact
actuation unit is formed. At the end of the pressing process, an
excess pressure is generated in the cylinder and leads to opening
of a pressure relief valve and hence to the end of the pressing
process. Before the next pressing process, the piston is reset by a
reset spring with recycling of the liquid into a collecting region.
The pressing tools according to the prior art can be used with many
different, changeable pressing jaws. The various pressing jaws are
formed for pressing copper and steel fittings or for connecting
plastics pipes having different diameters in each case.
[0005] For fastening the various pressing jaws, pressing tools have
a fork-like connecting part in which the pressing jaws are inserted
and are fastened to the pressing tool by means of a fastening pin.
The various pressing jaws therefore have, in their connecting
element, a hole through which the fastening pin is inserted. The
connecting part likewise has a hole which receives the fastening
pin and in which the latter is secured. The fastening pin must be
completely inserted into the hole in the connecting part in order
to ensure that the pressing tool functions satisfactorily. For
various reasons, it is found again and again that the fastening pin
is not properly inserted, and this has already led to accidents.
The publication EP-0941813-A1 discloses a pressing tool which
carries out a check to ensure that the fastening pin is locked
during operation, in order to prevent such accidents. As long as
the fastening pin is not properly secured, a warning signal is
triggered. A presence check with respect to the pressing jaw is
also performed. The disadvantage is that the pressing process as
such is not terminated when a pressing jaw is missing or has been
incorrectly inserted.
SUMMARY OF THE INVENTION
[0006] It is the object of the invention to make an improvement in
the safety of such a pressing tool. In addition, a pressing process
of the pressing tool should be capable of being triggered only when
the presence of a pressing jaw has been ensured.
[0007] In achieving the object, it was recognized that the safety
of the pressing tool can be increased by means of a pressing jaw
presence check. In contrast to publication EP-0941813-Al, however,
the pressing jaw presence check leads to the pressing tool being
switched off if no pressing jaw is present or if the latter becomes
detached from the pressing tool during the pressing process. The
pressing jaw presence check is intended to be a check which also
safely functions in the case of severe soiling and in a moist
environment. It is therefore preferable to use a sensor which
measures without contact and which makes it possible to determine a
field property which is clearly distinguishable with present and
absent pressing jaw.
[0008] For this purpose, it is possible to provide, for example on
the pressing jaw, a presence magnet which is detectable by a
presence Hall sensor of the pressing tool. Because old pressing
jaws or pressing jaws from other manufacturers should also be
capable of being used, it is however advantageous to use for the
presence check an inductive sensor which makes it possible to
detect the presence of any pressing jaw. However, it is also
possible to use other sensors or mechanical switches which respond
on contact.
[0009] With such a sensor for the presence check, it is possible to
carry out a pressing process in which the pressing can be carried
out safely using all usable pressing jaws. In the pressing process,
initialization steps or initialization tests are envisaged after
the pressing tool has been switched on. Before it is possible to
trigger the pressing process, a presence check is carried out to
determine whether a pressing jaw has been inserted or not. If no
pressing jaw is present, an acoustic and/or optical warning signal
is triggered and the presence check is then carried out again. If,
after a delay, a pressing jaw still has not been inserted or has
been poorly inserted, the pressing tool is switched off or the
pressing process cannot be triggered. In order to trigger a
pressing process again, the pressing jaw must be introduced into
the pressing tool and fastened to the pressing tool by means of the
fastening pin. If a pressing jaw was already present, it must be
ensured that the pressing jaw is correctly inserted into the
connecting part. If the presence control detects that a pressing
jaw has been inserted, an allocation check is carried out after a
short delay. If there is no allocation, a standard range or
standard values is or are assigned, as described in detail in the
publication EP-0941813-A1. Thus, this publication states that a
piston position range value is assigned to the piston connected to
the piston rod, which value corresponds to the pressing jaw used in
each case. The instantaneous piston position is detected by a
measuring means and compared with the piston position range value.
If the value for the instantaneous piston position and the piston
position range value agree, or the instantaneous piston position is
within a tolerance range around the piston position range value,
the pressing procedure is found to be satisfactory; otherwise,
pressing is recognized as incorrect.
[0010] As a further check before the triggerability of a pressing
process is enabled, a locking check is carried out. For carrying
out the locking check, the pressing tool has at least one locking
sensor measuring without contact. If the fastening pin is not
locked or is not in the securing position, this is detected by the
locking sensor and indicated at least by means of an acoustic
and/or optical warning signal. Optionally, the locking check is
repeated until the fastening pin is locked or secured. After a
delay to enable the operator to carry out the locking of the
fastening pin properly, the pressing tool may be ready for
triggering a pressing process.
[0011] Before it is made possible for a further pressing process to
be triggered, the sequence already described above and comprising a
pressing jaw presence check, which detects whether a pressing jaw
has been inserted or not, a locking check and an allocation check
is carried out again. In order to ensure that a pressing jaw cannot
be removed and then a pressing process triggered after these
checking steps, the checking steps are repeated at specified time
intervals optionally at least during the triggering actuation for a
pressing process. If no pressing process is triggered for a
specified maximum rest time, the pressing tool is switched off.
BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate the
invention purely by way of example with reference to an
embodiment.
[0012] FIGS. 1a and 1b show a connection region of a pressing tool
with inserted pressing jaw and secured fastening pin and
[0013] FIG. 2 shows a flow diagram for the pressing process.
DETAILED DESCRIPTION OF THE INVENTION
[0014] FIG. 1a shows a fork-like connecting part 7 of a pressing
tool, FIG. 1b a section thereof, comprising a piston rod 6,
pressing rollers 28 and a guide block 29 which is guided in a
linear guide 30. The linear guide 30 is fastened to a cylinder part
5 and has, in the region of the fork-like connecting part 7, a hole
31 for receiving a fastening pin 50 by means of which a pressing
jaw 51 is fastened. The pressing jaw 51 consists of a fastening
part 51c, which is connected to a connecting element 51d, and in
which two cheek plates 51a and 51b are each pivotably mounted about
an axis 9a and 9b of rotation, which axes 9a and 9b of rotation are
at right angles to the plane of the drawing. The cheek plates 51a
and 51b have actuation surfaces 8a and 8b which rest against the
pressing rollers 28 during a pressing process 44 (cf. FIG. 2). The
actuation surfaces are formed in such a way that the pressing
rollers 28 moving forwards cause the cheek plates 5a and 51b to
move together, by means of pivot movements about their axes 9a and
9b of rotation, in the region of a fitting 32a to be pressed, the
fitting 32a being inserted into an orifice 32 in the pressing jaw
51 together with the pipe ends to be connected.
[0015] In order to permit a pressing jaw presence check 45 (cf.
FIG. 2), a presence sensor 52 measuring without contact is
preferably arranged in the linear guide 30 in such a way that it
makes it possible to determine a field property which is clearly
distinguishable with present and absent pressing jaw 51. For this
purpose, a presence magnet which is detectable by a Hall sensor as
a presence sensor 52 of the pressing tool can be provided, for
example on the pressing jaw 51. Preferably, however, an inductive
sensor is used, which makes it possible to detect the presence of
any metal pressing jaw 51, even if no presence magnet is provided
in the pressing jaw 51. Alternatively, however, it is also possible
to use a sensor responding to contact, such as, for example, a
pressure sensor, or a mechanical switch as presence sensor 52. If
the pressing jaw 51 is present, it must also be ensured that the
fastening pin 50, which connects the pressing jaw 51 to the
pressing tool, has been correctly inserted. The fastening pin 50
has a grip 50a which is transverse to the pin axis and is aligned
in a first direction on insertion of the fastening pin 50. In this
orientation, a longitudinal pin groove 50b receives a guide pin 53
which, when the fastening pin 50 has been completely inserted,
rests in an annular groove 50d so that the fastening pin 50 is
rotatable through 180.degree. in a locking position. A locking
check 47 (cf. FIG. 2) envisages that the fastening pin 50 can be
checked in the locking position. For this purpose, the grip 50a is
preferably provided with a locking magnet 50c which, in the locked
state or in the locking position, is adjacent to a locking Hall
sensor 54 in the pressing tool. If the locking Hall sensor 54
detects the locking magnet 50c, the locking pin 50 is in the
locking position. if the check for locking is negative, a warning
signal is triggered without the start procedure of the pressing
tool necessarily being interrupted. Of course, it is also possible
to use, for example, an inductive sensor instead of the Hall
sensor.
[0016] FIG. 2 shows a pressing process for tightly pressing on
sleeve-like fittings 32a using a pressing tool which actuates the
clamping movement of at least one cheek plate 51a or 51b via a
piston rod 6 and a transmission device (cf. FIG. 1). By means of an
on/off switch, the pressing tool is switched on in a switch-on step
41. A self-test, start test and service test are then performed in
an initialization step 42. Before a pressing process 44 together
with determination of operating parameters can be triggered in a
triggering step 43, it is necessary, in a repeatable second step,
to determine whether the pressing tool is ready for triggering a
pressing process 44. In the second step, a pressing jaw presence
check 45 is carried out until a pressing jaw 51 (FIG. 1) has been
inserted. As long as no pressing jaw 51 is present, an acoustic
and/or optical warning signal 45a is triggered or maintained. If,
after a delay, a pressing jaw 51 still has not been inserted, the
pressing tool can be switched off by a time-lag means 45b. If a
pressing jaw 51 has been inserted, an allocation check 46 is
carried out after a delay, as described in publication EP
0941813-A1, in order to assign a piston position range value to the
inserted pressing jaw 51. If allocation information is absent, a
standard range allocation 46a is performed. As a further checking
step prior to enabling the triggerability of a pressing process 44,
a locking check 47 is preferably carried out in order at least to
trigger a warning signal 47a if a fastening pin is not secured.
After these checking steps have been successfully carried out, the
pressing tool is ready for triggering a pressing process 44. If the
fastening pin 50 (FIG. 1) has not been properly locked, the ready
state for the pressing process 44 is enabled only after a delay by
a second time-lag means 47b, in order to give the operator the
possibility of locking the fastening pin 50. If the pressing
process 44 is not triggered within a specified time, a rest time
monitor 43a checks whether the device has remained switched on for
a specified maximum rest time without a pressing process 44. If the
maximum rest time has not yet been reached, the device runs through
the second step or the checking steps 45-47 again. If the maximum
rest time has been reached, the pressing tool is switched off.
Before it is possible to trigger a further pressing process 44, the
checking steps 45-47 must be carried out again.
* * * * *