Closure fasteners – Bolts – Sliding
Reexamination Certificate
2002-08-27
2004-05-18
Sandy, Robert J. (Department: 3677)
Closure fasteners
Bolts
Sliding
C292SDIG004, C292S302000, C292S341150
Reexamination Certificate
active
06736433
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the priority of German Patent Application Serial No. 101 41 835.3, filed Aug. 27, 2001, the subject matter of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a device for locking at least two protective doors of an industrial machine, in particular the doors of an injection molding machine.
BACKGROUND OF THE INVENTION
Many machines have protective doors to protect bystanders and operators of these machines. The protective doors should be allowed to open only when the process does no longer pose a risk. Otherwise, opening the protective doors when the machine is running will trigger an emergency stop. When all protective doors are closed, the state of the machine is switched to a ready state.
FIG. 1
shows a conventional device for locking a protective door
2
. This device includes a momentary contact switch
4
, a device for recognizing that the door(s) is/are closed, and an electromechanical lock
8
. The momentary contact switch
4
is located on a door handle
10
of the protective door
2
. The functionality of the momentary contact switch
4
can also be implemented using other devices. The functionality of the momentary contact switch can also be implemented at other locations of the industrial machine, for example in a machine control panel. The electromechanical lock
8
, in particular the protective door lock, has an actuator
12
and a receiving device
14
adapted to engage with the actuator
12
. In the illustrated embodiment, the actuator
12
can move in an axial direction as indicated by a double arrow
16
. The actuator
12
is moved by an electric device
18
. In the locked state, the actuator
12
is located inside the corresponding receiving device
14
, which in the simplest case is a plate
20
with an opening
22
. A sensor device
6
, such as a protective door contact
6
, is also closed in the locked state, indicating that the protective door
2
is indeed closed.
If the protective door
2
is to be opened, then the command “Move machine/process into a safe state” is triggered using the momentary contact switch
4
on the protective door
2
. In response to the command “Move machine/process into a safe state”, the electric device
18
of the electromechanical door lock
8
receives a control signal to move the actuator
12
away from the receiving device
14
in an axial direction. After the receiving device
14
is released, the protective door
2
can be opened and withdraws from the protective contact
6
. The “open” and “close” motion of the protective door
2
is indicated by another double arrow
24
.
If an industrial machine, for example an injection molding machine, includes several protective doors
2
and
26
(see FIGS.
2
and
3
), then each protective door
2
and
26
is provided with a device of the type described with reference to
FIG. 1
for locking the protective door
2
and/or
26
. On an injection molding machine, the two protective doors
2
and
26
are referred to as “mold closing door” and “ejector door”. It can be technically complex and expensive to protect an operator of such an injection molding machine.
It would therefore be desirable to provide a device than can simultaneously lock several protective doors of an industrial machine.
SUMMARY OF THE INVENTION
According to one aspect of the invention, at least two protective doors of an industrial machine, in particular an injection molding machine, can be locked simultaneously with a single locking device which includes a momentary contact switch, a device for recognizing a closed state of the protective door and a mechanical lock having an actuator with an associated receiving device, wherein one of the protective doors has at least one non-energizable actuator whose corresponding receiving device is associated with the second protective door.
This device advantageously eliminates for each additional protective door one electromechanical lock, one device for recognizing the locked state and one momentary contact switch. This design reduces the wiring cost and obviates the need for additional digital inputs and outputs of a machine controller. However, when using this particular device of the invention, the protective door that is equipped with the non-energizable actuator and the electromechanical lock, must be the last protective door closed, since this door is responsible for locking the other protective doors.
According to another aspect of the invention, a device for locking at least two protective doors of an industrial machine, in particular an injection molding machine, includes a momentary contact switch, a device for recognizing a closed state of the protective doors and a mechanical lock having an actuator with an associated receiving device. The actuator includes a transfer device with at least two additional actuators that engage with corresponding receiving devices that are each associated with a protective door.
With this arrangement, several protective doors can be locked simultaneously with a single electromechanical locking device. The transfer device transfers the locking motion of the actuator of the electromagnetic lock to additional spatially separated actuators. This locking device for locking several protective doors also reduces the number of additional components and the technical complexity. Unlike the first device, this device does not require that the protective doors are locked in a particular sequential order. The electromechanical locking device is only actuated after all protective doors are locked, locking all protective doors simultaneously, independent of their spatial arrangement.
Embodiments of the invention may include one or more of the following features. The energizable actuator and the at least one non-energizable actuator are implemented as a bolt, with the receiving device being in form of an opening. A sensor device can be disposed on at least one of the protective doors for recognizing a closed state of the at least two protective doors. The sensor device, which can be a protective contact, and the mechanical lock can be arranged on opposite sides of a protective door.
The transfer device can include a plate, for example a plate having a triangular shape, in with case the at least two additional actuators can be arranged on the side of the plate that faces away from the energizable actuator.
The device can advantageously be used with an injection molding machine that has as one of the protective doors a closing door and as another one of the protective doors a discharge door.
Further features and advantages of the present invention will be apparent from the following description of preferred embodiments and from the claims.
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patent: 3309816 (1967-03-01), Malone
patent: 4930836 (1990-06-01), Grinn
patent: 5197771 (1993-03-01), Kaup et al.
patent: 5241787 (1993-09-01), Norman
patent: 6367852 (2002-04-01), Aspenwall
patent: 6374651 (2002-04-01), Thielmann et al.
patent: 298 12 820 (1998-10-01), None
patent: 198 09 246 (1999-09-01), None
patent: 200 21 938 (2001-07-01), None
patent: 1087079 (2001-03-01), None
patent: 2001165393 (2001-06-01), None
Feiereisen Henry M.
Melwani Dinesh N
Sandy Robert J.
Siemens Aktiengesellschaft
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