WO2002071552A1

WO2002071552A1 - Disengagement detection arrangement

Info

Publication number: WO2002071552A1
Application number: PCT/NO2002/000044
Authority: WO
Inventors: Knut Foseide
Original assignee: Safety Cable As
Priority date: 2001-02-02
Filing date: 2002-02-01
Publication date: 2002-09-12
Also published as: WO2002071552A9; AU2002230311A1; NO20010588D0

Abstract

The invention relates to a detection device which consists of a pressure transmission mechanism for use in detecting that a male contact is connected to its respective female contact. The solution can be used in all apparatus which have to detect that a male contact is physically disconnected from its associated female contact. A pressure transmission mechanism is placed inside a hollow pole arm in a male contact, and a pin on the force transmission arm creates friction against the internal walls of the female plugwhen the male contact is pulled out, thereby causing the pressuretransmission arm to make a movement relative to the male contact which can be detected by a sensor placed inside the male contact in connection with the force transmission arm.

Description

Device for disconnection detection

The invention relates to a detection device consisting of a pressure and/or tension transmission mechanism in a contact arrangement which is capable of detecting that a male contact, preferably an electric male contact, is being disconnected from a respective female contact, preferably an electric female contact. The solution can be used in all apparatus which have to register that the male contact is physically disconnected from its respective female contact.

In order to detect that a male contact is connected to its respective female contact, the only requirement in principle is a simple mechanism which could be a sensor of many types. This could be a simple microswitch (which is used as an example in this application), or it could consist of light emitting diodes/phototransistors, magnetic switches (for example, a magnetic or Hall sensor or magnetic or Hall element), or other known techniques for sensing cable breaks. However, in the male contact there is often limited space for the installation of the sensor, and in cases where this mechanism is to be used to detect disconnection in order to trigger a signal, as for instance a burglar alarm, it is essential that the detection mechanism on the sensor (for example, the microswitch) is not easily accessible to a person who, unauthorised to do so, tries to disconnect the male contact from the female contact.

The detection mechanism according to this invention is arranged so as to be inaccessible, thus preventing an unauthorised person from having the opportunity to manipulate it.

The detection mechanism according to the invention can, for example, be used in a burglar alarm fitted with alarm signals of all types, as for example, sound, RF, GSM, GPS etc. which will be triggered when the male contact is disconnected from the female contact.

Detection of the disconnection of the male contact from the female contact is effected according to the invention in that the pin on a transmission arm which passes through a hollow pole arm, or contact pin, in the male contact has an external diameter which is greater than the external diameter of the hollow pole arm, so that when the male contact is pulled out of the female contact there will be greater friction between the transmission arm and the internal walls of the female contact, preferably greater than the friction between the hollow pole arm itself and the internal walls of the female contact. The transmission arm, which, inside the male plug for example, (many types of sensors may be used), can be held under spring-loaded tension against a microswitch, so that the microswitch is held in when the male contact is right inside the female contact, will, when the pin is "held back" by the friction against the internal walls of the female contact, stick a little inside the female contact and move the transmission arm relative to the male contact, so that the tension against the microswitch ceases and the microswitch clicks out (and can, for example, activate an alarm). The pin on the transmission arm may also be ball or egg-shaped (alternative 1) so that it will not stick at all inside the female contact, but will simply generate sufficient friction to be moved enough to trigger the sensor. The transmission arm pin may also be resilient so as to permit a temporary reduction in the external diameter of the pin on withdrawal of the male contact, so that if the friction against the internal walls of the female contact is greater than necessary to trigger the sensor, the transmission arm will disengage and slide out of the female contact.

A detection mechanism according to the invention, where a force transmission arm lies inside a hollow pole arm in a male contact, is characterised in that a pin on the force transmission arm is held back by the female plug when the male plug is pulled out, thereby causing the force transmission arm to make a movement relative to the male contact which can be detected by a sensor placed inside the male contact.

An additional advantageous feature of a detection mechanism according to the invention is further characterised in that the pin on the force transmission arm has an external diameter that is greater than the external diameter of the hollow pole arm in which the force transmission arm lies.

An additional advantageous feature of a detection mechanism according to the invention is further characterised in that the pin (4) on the force transmission arm at the rear edge has an edge which creates friction in that the edge butts against irregularities in the internal walls (6) of the female contact when the male contact is pulled out of the female contact. The friction causes the force transmission arm to move inside the hollow pole arm, thereby triggering a sensor in the male contact.

An additional advantageous feature of a detection mechanism according to the invention is further characterised in that the pin (4) on the force transmission arm is resilient, so that the external diameter of the pin is reduced on disconnection /connection of the female plug and the male plug. The spring force of the pin (4) is greater than the spring force of the spring member (7) at back edge of the force transmission arm, so that the sensor is triggered before the external diameter (Dy 1) of the pin (4) becomes smaller than the diameter (Dy 3) of the internal walls of the female contact and the male contact slides out of the female contact.

An additional advantageous feature of a detection mechanism according to the invention is further characterised in that the pin (4) on the force transmission arm has an entering guide in the front which means that it more easily positions itself in the centre of the hole in the pole arm in the female plug, so that the resilient internal walls of the female contact will reduce their external diameter to less than the diameter (Dy3) of the internal walls of the female contact, and provide space for the male contact in the female plug.

An additional advantageous feature of a detection mechanism according to the invention is further characterised in that the pin (4) on the force transmission arm has a spring mechanism (7) at the rear edge, which normally, exerts pressure on a microswitch that holds the switch in a constantly closed position. When the male contact is pulled out of the female contact, the spring mechanism (7) will be pulled away from the microswitch so that the microswitch is opened.

In a first alternative (alternative 1) embodiment of the invention, the transmission arm passes through the length of the hollow pole arm.

In a second embodiment (alternative 2), the transmission arm can only pass two-thirds (2/3) of the way through the hollow pole arm, so that the transmission arm pin projects from the hollow pole arm through holes in the hollow pole arm, which means that the external diameter of the transmission arm pin in this alternative is also greater than the external diameter of the hollow pole arm.

When the male contact is pulled right out of the female contact, the spring member of the pressure arm that is located inside the male contact will draw the rest of the transmission arm back into the starting position.

In the above description, the internal walls (6) of the female contact may be the actual plastic walls in the female contact, but could just as easily be the metal parts of the female contact which make contact with the male contact pole arm, and which also form "walls" inside the female contact according to the inventor's definition. In what follows the invention will be described with the aid of examples, with reference to the attached figures, wherein:

Figure 1 shows an example of a male contact (2) according to the invention which is - fully inserted in a respective female contact (3).

Figure 2 shows a situation where the male contact (2) is being pulled out of the female contact (3).

Figure 3 is a perspective view of the male contact (2) including the associated elements of the invention.

Figure 4 is a perspective view of the female contact (2) including the associated elements of the invention.

Figure 5 shows an alternative embodiment (alternative 2) of the force transmission arm (1).

Referring to Figure 1, Dyl indicates the external diameter of the pin (4) on the force transmission mechanism, Dy2 indicates the external diameter of the hollow pole arm or the contact pin on the male contact through which a pressure transmission arm passes, whilst Dy3 indicates the internal diameter of the internal walls (6) of the female contact. When the male contact (2) is fully connected to the female contact (3), the spring member (7) arranged on the force transmission arm inside the male contact exerts a force on the force transmission arm which acts in the direction of the microswitch. The pressure transmission arm in this situation is not subjected to compressive or tensile forces exerted by the female contact, and thus in this example the microswitch is maintained in the situation shown in Figure 1 in a closed position.

Referring to Figure 2, the pin (4) on the pressure transmission arm (1) is held back by the friction against the internal walls (6) of the female contact, so that the spring member (7) of the pressure transmission arm (1) is put under tension. With a frictional force between the pin (4) and the female contact that is greater than the force exerted by the biasing spring (7), the pin is moved and in this case thus allows the microswitch (8) to click out in the open position. Since the pin (4) on the pressure transmission arm (1) may be resilient, it can be seen in Figure 2 that the external diameter (Dy4) of the pin (4) when the pin is pulled out through the internal walls (6) of the female contact, is reduced and becomes smaller than the external diameter (Dyl) of the pin (4) when the male contact is fully connected to the female contact (as in Figure 1).

Referring to Figure 5, the pole arm (5) is not hollow throughout, so that the pressure ^• transmission arm pin (4) projects from a point on the pole arm, for example on a side of the pole arm. The detection mechanism consists of a force transmission mechanism (1) which is used to detect that the male contact (2) is connected to its respective female contact (3). The solution can, for example, be used in a burglar alarm device where an alarm is to be triggered if a male contact (2) is physically disconnected from its associated female contact (3). Detection of the connection of the male contact (2) to the female contact (3) is effected according to the invention in that the pin (4) on a transmission arm (1) which passes through a hollow pole arm (5) in the male contact (2) has an external diameter (Dyl) that is greater than the external diameter (Dy2) of the hollow pole arm, so that when the male contact is (2) is pulled out of the female contact (3) there is greater friction between the transmission arm pin and the internal walls (6) of the female contact than the friction between the actual hollow pole arm and the internal walls of the female contact. The transmission arm (1), which inside the male contact (2), for example, (sensors of various types may be used) can be held under spring-loaded tension (7) against a microswitch (8) so that the microswitch is held in when the male contact (2) is right inside the female contact (Figure 1), will, when the pin is "held back" by the friction against the internal walls of the female contact, stick a little inside the female contact (3) and move the transmission arm (1) relative to the male contact (2), so that the tension against the microswitch ceases and the microswitch clicks out as shown in Figure 2 (and can, for example, activate an alarm). The pin on the transmission arm may also be made in the form of a ball so that it will not stick at all inside the female plug (3), but will simply create sufficient friction to trigger the sensor. The transmission arm pin (4) may also be resilient, for example in a direction substantially transverse to the longitudinal direction of the force transmission arm, and permit a temporary reduction of the outer diameter (Dyl, Dy4) of the pin on withdrawal of the male contact (2) so that if the friction against the internal walls (6) of the female contact can be controlled to be no greater than necessary to trigger the sensor (8), whereby the transmission arm (1), when the male contact is drawn out of the female contact, can gradually disengage and with sufficient resistance slide out of the female contact (3).

In the embodiment according to alternative 1 , the transmission arm passes through the length of the hollow pole arm. In a second embodiment (alternative 2), the transmission arm is only intended to pass through two-thirds (2/3) of the hollow pole arm, so that the transmission arm pin projects from the hollow pole arm through holes in the hollow pole arm. This means that the external diameter of the transmission arm pin in this alternative is preferably greater than the external diameter of the hollow pole arm. When the male contact (2) has been withdrawn fully from the female contact (3), the spring member (7) of the pressure arm located inside the male contact will draw the rest of the transmission arm (1) back into the starting position.

Typically, the detection mechanism of the invention consists of a force transmission mechanism for use in registering that the male contact is connected to its respective female contact. The solution can be used in all apparatus which have to detect that a male contact has been physically disconnected from its associated female contact. A pressure transmission mechanism is placed inside a hollow pole arm in a male contact, and a pin on the force transmission arm creates friction against the internal walls of the female contact when the male contact is pulled out, thereby causing the pressure transmission arm to make a movement or shift relative to the male contact, which movement or shift is detected by a sensor placed inside the male contact in connection with the force transmission arm.

Although the invention has been described with the aid of examples where a biasing spring (7) consists of a part of the force transmission arm, the invention could just as easily be made with other spring devices for biasing the force transmission arm, as for instance a spiral spring placed around the arm, resting against the arm on one side of the spring and against the contact housing on an opposite side. Alternatively, the biasing of a microswitch can be provided in the switch itself, thereby eliminating the need to bias the force transmission arm. Other biasing solutions are also possible, and could easily be specified by a skilled person when the skilled person has become familiar with the description of the invention. Without a biasing spring in connection with the force transmission arm, or another device for holding the arm in position, the arm would float freely. Means other than a microswitch can be used for sensing the position of the force transmission arm, and a sensing means of the switch type, as for instance the microswitch in the example that is used to explain the invention, may depend upon the properties of an attached apparatus which is to make use of information from the sensing means in normally open or normally closed mode.

Claims

P a t e n t c l a i m s

1.

A detection device in a contact, characterised in that it comprises an elongate force transmission arm arranged in a hollow pole arm or contact pin in a male contact, which force transmission arm is provided with a pin so arranged that when the male contact is inserted into and connected to a corresponding female contact, the force transmission arm will be held back by the female contact when the male contact is pulled out of the female contact, whereby the force transmission arm relative to the male contact is caused to make a movement which is detectable by means of a sensor arranged in the male contact.

2.

A detection device according to claim 1, characterised in that the pin on the force transmission arm has an external diameter that is greater than the external diameter of the hollow pole arm.

3.

A detection device according to claims 1-2, characterised in that the pin (4) on the force transmission arm at the rear edge has an edge, the edge being arranged to butt against irregularities in the internal walls (6) of the female contact when the male contact is pulled out of the female contact.

4. A detection device according to claims 1-3, characterised in that the pin (4) on the force transmission arm is resilient in a direction substantially transverse to the longitudinal direction of the force transmission arm, so that the outer periphery of the pin is reduced when the male contact is inserted into and connected to a corresponding female contact of smaller diameter than the diameter of the pin in its original state.

5.

A detection device according to claim 4, characterised in that the spring force in the pin (4) is greater than the spring force of the spring member (7) at the back edge of the force transmission arm, so that the sensor is triggered before the external diameter (Dyl) of the pin (4) becomes smaller than the diameter (Dy3) of the internal walls of the female contact when the male contact is removed from the female contact.

6.

A detection device according to claims 1-4, characterised in that the pin (4) on the force transmission arm has an entering guide in the front which means that it can more easily position itself in the centre of the hole of the pole arm in the female plug, so that the - 5 resilient internal walls of the female plug will reduce their external diameter to less than the diameter (Dy3) of the internal walls of the female contact, and provide space for the male contact in the female plug.

7. lo A detection device according to claims 1-2, characterised in that the force transmission arm has a spring mechanism (7) at the back edge which is arranged to normally be in engagement with and exert biasing pressure on a microswitch to hold the microswitch in a constantly closed position, and that the spring mechanism (7) will reduce the biasing pressure when the male contact is pulled out of the female contact and is pulled away l s from the microswitch so that the microswitch is _^opened.