WO2013069001A1

WO2013069001A1 - Electromechanical apparatus for establishing/interrupting a connection with telephone electrical conductors made of metal

Info

Publication number: WO2013069001A1
Application number: PCT/IB2012/056359
Authority: WO
Inventors: Silvano Mura
Original assignee: Auxitel S.P.A.
Priority date: 2011-11-11
Filing date: 2012-11-12
Publication date: 2013-05-16
Also published as: ITTO20111043A1

Abstract

The present invention relates to the fixed telephony sector and refers to an electromechanical apparatus (1) capable of establishing/interrupting a connection with telephone electrical conductors made of metal, in particular capable of intercepting pairs of telephone electrical conductors made of metal in a telephone exchange. The electromechanical apparatus (1) according to the invention comprises a selecting device (13) provided with a sliding carriage (17) on at least one side of which there is provided an actuator (29a,29b) which can be controlled to move from a first passive position, in which it does not interact with the switching blades (11 a, l ib) corresponding to said pairs of telephone electrical conductors made of metal, to a second active position, in which it acts upon one of said switching blades (1 la,l lb) bringing it into a switching position, in which it is in contact with a corresponding contact pad (37a,37b) and in which, thanks to said connection, it can be tested.

Description

ELECTROMECHANICAL APPARATUS FOR ESTABLISHING/INTERRUPTING

A CONNECTION WITH TELEPHONE ELECTRICAL CONDUCTORS MADE OF METAL

DESCRIPTION

Field of the invention

The present invention relates to the telephony sector, more precisely, but not exclusively, to the fixed telephony sector.

Specifically, the present invention refers to an electromechanical apparatus capable of establishing/interrupting a connection with electrical conductors; in particular the present invention refers to an electromechanical apparatus for intercepting the pairs of telephone electrical conductors made of metal present in a telephone exchange.

Description o f the prior art

Generally speaking, a telephone exchange is a switching centre for a public or private telephone network.

A telephone exchange comprises permutation devices - i.e. devices for switching, converting or connecting in a telephone network - which contain terminal strips against which the pairs of metal telephone electrical conductors from the telephone network are abutted.

Each terminal strip is a modular element and comprises a plastic or metal base capable of supporting several terminal/s witching modules. For example, a terminal strip in a telephone exchange can be implemented so as to receive 100 pairs of metal telephone electrical conductors.

Electromechanical apparatus suitable to be coupled with said terminal strips to intercept said pairs of metal telephone electrical conductors are known in the prior art.

In particular, said electromechanical apparatus are used when there is the need to test the correct operation of the telephone network and allow the metal telephone electrical conductors to be connected to the circuit of the test and measurement instruments used to evaluate the efficiency of the metal telephone electrical conductors being tested.

The Applicant has already developed an electromechanical apparatus of the type described above, which advantageously has a simple structure and a limited number of parts, to achieve increased reliability.

With reference to Figures la - lc, in said prior art apparatus 100, thanks to a printed interception circuit board, the signals of the pairs of metal telephone electrical conductors are acquired by the terminal strip and sent to a main printed circuit board 110 which is provided with mechanical devices 120 that switch said pairs, thus enabling them to be tested.

Each of said mechanical devices 120 comprises an external casing 122 which is suitable to be applied to said main printed circuit board and which internally houses a first frame 124 which bears a selector 126 movable along a shaft 128 and a second frame 130 which bears the switching blades 132. Contact blades 134 are mounted on the bottom face of said selector 126. When the selector 126 is moved to a given axial position along the shaft 128, the contact blades 134 intercept corresponding switching blades 132 making these move from a resting or short-circuit position, in which they come into contact with a respective contact pad on the main printed circuit board, to an operating or switching position, in which they can be tested thanks to the connection that is established with the contact blades 134.

In the apparatus illustrated in Figures la - lc, the switching blades 132 are installed on the face of the main printed circuit board 110 opposite the face on which the selector 126 is mounted and said main printed circuit board 110 is provided with appropriate holes so that the ends of said blades protrude from said opposite face, so as to be able to come into contact with the contact blades 134. Said contact blades 134 are shaped so as to achieve the necessary pre-load to guarantee the contact with the contact pads on the main printed circuit board 110 when they are in the resting position.

Although the electromechanical apparatus described above is a simple and robust construction with a limited number of parts, it is not without drawbacks.

In the first place, when - under the action of the contact blades - the switching blades move from the resting position to the operating position, there is the non-negligible possibility of these interfering with the walls of the hole in the main printed circuit board through which they move, and the subsequent risk or them jamming.

Secondly, given the need to obtain a hole for each switching blade in the main printed circuit board, the density of switching blades that can be provided on said printed circuit board cannot be increased beyond a certain limit, imposed by the actual geometry of said printed circuit board and the strength of the material used to make the printed circuit board.

Lastly, both faces of the main printed circuit board are occupied by parts of the mechanical switching devices (by the switching blades and the selector, respectively). The purpose of the present invention is to provide an electromechanical apparatus for establishing/interrupting a connection with telephone electrical conductors made of metal that overcomes the drawbacks mentioned above and guarantees increased reliability and a lower risk of malfunction and which allows the density of switching blades present on the main printed circuit board to be increased.

This and other purposes are achieved with the electromechanical apparatus according to the invention, as claimed in the appended claims.

Brief summary of the invention

The selecting device of the electromechanical apparatus according to the invention comprises a carriage on at least one side of which, preferably on both sides, is an actuator that can be controlled to move from a first passive position, in which it does not interact with the switching blades, to a second active position, in which it acts upon a corresponding switching blade to move it from the resting position to the switching position.

According to a preferred embodiment of the invention, said actuators are cams.

Given the structure of the selecting device according to the invention, the switching blades and the selecting device can be mounted on the same face of the main printed circuit board, thus avoiding the need to drill holes in said board.

Advantageously, this avoids the risk of the switching blades being obstructed in their passage from the resting or short-circuit position to the operating or switching position. Moreover, the density of the switching blades on the main printed circuit board can be increased significantly, and even doubled.

Brief description of the drawings.

Further characteristics and advantages of the present invention will become clear from the following detailed description of a preferred embodiment thereof, provided by way of non-limiting example, with reference to the accompanying drawings, in which:

- Figure la is a schematic exploded perspective view of an electromechanical apparatus for intercepting pairs of metal telephone electrical conductors known in the prior art;

- Figure lb is a schematic exploded perspective view of a known mechanical switching device of the electromechanical apparatus shown in Figure la;

- Figure lc is a schematic perspective view from below of the selecting device of the known mechanical switching device shown in Figure lb; - Figure 2 is a front view of the base body of an electromechanical apparatus for intercepting telephone electrical conductors made of metal according to a preferred embodiment of the invention;

- Figure 3 is a front view of the closing cover of the electromechanical apparatus shown in Figure 2;

- Figure 4 schematically illustrates the overlap of the base body shown in Figure 2 and the closing cover shown in Figure 3;

- Figure 5 is a schematic cross-sectional view along the plane V-V of Figure 4;

- Figure 6 shows an exploded perspective view of the selecting device of the electromechanical apparatus according to an alternative embodiment of the apparatus shown in Figures 2 - 5, in which for the sake of simplicity only one actuator is shown;

- Figure 7 schematically illustrates a detail of the selecting device in Figure 6, shown as it acts upon a switching blade.

Detailed description of a preferred embodiment of the invention.

With reference to Figures 2 - 4, there is illustrated an electromechanical apparatus 1 for intercepting pairs of metal telephone electrical conductors according to the invention. The apparatus 1 is suitable for being coupled with a terminal strip of a telephone exchange against which said pairs of metal telephone electrical conductors are abutted and can be used to test the corresponding telephone lines, in particular to test the correct operation thereof.

The electromechanical apparatus 1 comprises a casing which consists of a base body 3 (illustrated in Figure 2) and a closing cover 5 (illustrated in Figure 3).

As shown in Figure 2, a main printed circuit board, or main board 7 is mounted on the base body 3 and is provided with contact pads 9 which constitute the electronic component of the apparatus for process management and control.

The signals from the pairs of metal telephone electrical conductors acquired by the terminal strip of the telephone exchange are sent via specific intercepting printed circuit boards (not illustrated) to the contact pads 9 of the main printed circuit board 7.

Along a pair of opposite sides of the main printed circuit board 7 there are arranged a series of first switching blades 11a and a series of second switching blades l ib, respectively, each pair comprising a first 11a and a second 1 lb switching blade which are aligned and correspond to a pair of metal telephone electrical conductors, and thus to a telephone line to be tested.

The switching blades 1 la, 1 lb are normally in contact with the contact pads 9 on the main board 7 and are shaped so as to ensure a pre-load which guarantees the contact between said blades 1 la, 1 lb and said contact pads 9.

Said configuration is regarded as the "resting" configuration of the switching blades l la,l lb.

Between the series of first switching blades 1 1a and the series of second switching blades 1 lb there is provided a selecting device 13.

The selecting device 13 comprises a main threaded axis 15 on which a carriage 17 is slidingly mounted. The driving force to move the carriage 17 forward along the main axis 7 is generated by a corresponding motor, preferably a micro stepper motor 19, and is transferred to the carriage 17 via a series of toothed wheels 21, the main function of which is to gear down the speed of rotation of the motor by increasing the torque.

The carriage 17 of the selecting device 13, as it slides along the main axis 15, is suitable to be controlled remotely in order to move onto specific contact pads 9 of the main printed circuit board 7; the correct positioning of the carriage 17 on the desired contact pad 9 is guaranteed by an optical disc 23 fitted on the main threaded axis 15 which, by means of a conventional encoder, makes it possible to count the number of revolutions of said threaded shaft in real-time and thus to know the exact position of the carriage 17 in relation to a previously defined reference position.

According to the invention, the selecting device 13 of the electromechanical apparatus 1 also comprises a pair of secondary axes 25a,25b, mounted one at each side of the main axis 15, parallel to said main axis and preferably at the same distance from said axis.

The carriage 17 is appropriately shaped so as to slide without obstruction along the secondary axes 25a,25b. Said carriage 17 is also shaped so as to define in correspondence to said secondary axes a pair of seats 27a,27b, which house respective actuators 29a,29b fitted on said secondary axes 25a,25b.

Said actuators 29a,29b are driven by the carriage 17 as it translates and can be controlled by means of the respective secondary axes 25a,25b to move from a first position or passive position to a second position or active position, as described in greater detail below. The driving force to move said actuators from one position to the other is generated by corresponding motors, preferably micro stepping motors 31a,31b, and is transferred to said actuators 29a,29b via respective series of toothed wheels 33a,33b. Optical discs 35a,35b fitted on the secondary axes 25a,25b make it possible to guarantee the correct positioning of the actuators 29a,29b, using a conventional encoder.

Moving on now to Figure 3, along a pair of opposite sides of the inside face of the closing cover 5 there are provided a series of first contact pads 37a and a series of second contact pads 37b, respectively.

As is clearly shown in Figure 4 (where the base body 3 and the closing cover 5 are not illustrated for the sake of clarity), the first and second contact pads 37a,37b, are mounted on the inside face of the closing cover 5 so as to perfectly overlap the first and second switching blades 11 a, l ib once the closing cover 5 is mounted on the base body 3 of the apparatus. In particular, said first and second contact pads 37a,37b are perfectly aligned with respective first and second switching blades 11 a, l ib, at a certain distance from said blades.

With reference to Figure 5, this is a detailed illustration of the selecting device 13 and of the operation thereof.

As mentioned previously, the selecting device 13 comprises the carriage 17, which is driven to translate along the main threaded axis 15.

The carriage 17 is shaped so as to define a pair of longitudinal grooves 39a,39b in order to be able to slide without obstruction along the secondary axes 25a,25b.

In correspondence to said secondary axes 25a,25b, there are housed respective actuators

29a,29b in the seats 27a,27b specifically obtained in the carriage 17.

In particular, according to the embodiment illustrated in Figure 5, said actuators are cams

29a,29b fitted on the respective secondary axes 25a,25b.

As shown clearly in Figure 5, said cams 29a,29b can be controlled by means of the respective secondary axes 25a,25b to move from a first position or passive position - shown by the dashed line in Figure 5 - in which they do not interact with the switching blades 11 a, l ib, to a second position or active position - shown by the continuous line in Figure 5 - in which they act upon said switching blades 1 la, 1 lb.

In particular, the electromechanical apparatus 1 according to the invention functions as follows: - the carriage 17 is made to move forward along the main threaded axis 15 until it reaches the desired position, i.e. the position in which the cams 29a,29b are aligned with the switching blades 1 la*,l lb* corresponding to the telephone line to be tested;

- said cams 29a,29b are in a first position or passive position and said switching blades

1 la*, 1 lb* are in a first position or resting position (configuration illustrated by the dashed line in Figure 5), in which they are firmly in contact with the main printed circuit board 7 at the contact point d;

- the cams 29a,29b are controlled by the respective secondary axes 25a,25b to move from the first position to a second position or active position in which they intercept the end of the switching blades 1 la*, 1 lb* and cause them to move;

- under the action of the cams 29a,29b, the switching blades 1 la*, 1 lb* move from the first position or resting position to a second position or switching position in which the contact with the main printed circuit board 7 is interrupted and said switching blades are brought into contact with the corresponding superimposed contact pads 37a*,37b* at the contact point C₂ (configuration illustrated by the continuous line in Figure 5);

- at this point the corresponding telephone line can be tested.

Note that, although the two actuators 29a,29b are preferably activated simultaneously to move both of the switching blades 11a*, l ib* from the resting position to the switching position, the selecting device 13 is also structured to allow said actuators to be activated separately and independently of one another, if desired.

From the above description, it will be clear to the person skilled in the art that the electromechanical apparatus according to the invention overcomes several inconveniences associated with the apparatus known in the prior art.

In the first place, all the parts of said apparatus are mounted on the same face of the main printed circuit board 7, so that the opposite face of said printed circuit is completely free. Secondly, there is no need to drill holes in said main printed circuit board 7, thus simplifying the process of building the apparatus.

Thirdly, the structure of the apparatus according to the invention allows the density of the switching blades 11 a, l ib on the main printed circuit board 7 to be increased, so that a single selecting device 13 is able to operate on a much higher number of pairs of metal telephone electrical conductors. Consider, by way of example, a switching strip against which 100 pairs of metal telephone electrical conductors are abutted: with the electromechanical apparatus according to the invention, it would be possible to use just two apparatus, each capable of managing 50 pairs of conductors.

Figures 6 and 7 schematically illustrate some details relating to a possible alternative embodiment of the electromechanical apparatus 1.

For the sake of simplicity, in the following description of said alternative embodiment, the same reference numerals are used to indicate parts that are identical or similar to those described previously.

According to this alternative embodiment, the actuators 29a,29b of the selecting device 13 (only one of which is shown in Figures 6 and 7) are not cams, but substantially cylindrical bushings fitted on the respective axes 25a,25b and provided with a peripheral finger 41a suitable to act upon a switching blade when it is moved from the first position or passive position to the second position or active position.

Each actuator 29a,29b is housed in a seat 27a,27b obtained in the carriage 17, in such a way that its axial cavity 43a is aligned with the corresponding longitudinal groove 39a,39b provided in said carriage 17 for the passage of the secondary axes.

In that respect, note that the cross-section of the axial cavity 43 a of the actuator 29a is not round, but is flattened 45 a.

Correspondingly, the secondary axis 25a has a flattened cross-section 47a: said flattened cross-sections of the actuator and of the secondary axis cooperate so that said secondary axis is able to control the rotation of said actuator from said first passive position to said second active position and vice versa.

Clearly any other means of enabling the correct cooperation between the secondary axis and the corresponding actuator may also be used; for example, the secondary axis may be provided with a projection/recess suitable to cooperate with a corresponding recess/projection provided in the axial cavity of the corresponding actuator.

In Figure 6 positioning blades 53 provided on the face of the carriage 17 facing the main printed circuit board are shown clearly; said positioning blades 53 are suitable to cooperate with the contact pads of said printed circuit board to communicate the position of said carriage with respect to said printed circuit board. With particular reference to Figure 7, according to this alternative embodiment, the switching blades have a specific shape, which is particularly effective for preventing any deformation of said blades under the action of the actuators 29a,29b.

In particular, said switching blades 11a are shaped so as to define an abutment surface 49a for the peripheral finger 41a of the actuator 29a which is arranged so as to be parallel with the surface of said peripheral finger 41a when the latter comes into contact with the blade 11a. Moreover, said abutment surface 49a is joined to the point of contact with the corresponding contact pad 37a by means of a portion 51a arranged parallel to the direction of the force exerted by the actuator 29a on the switching blades when the latter are moved to the switching position.

This particular conformation increases the resistance of the switching blades and reduces the deformation thereof.

It is clear that the detailed description provided above is provided purely by way of example and that numerous modifications and variations may be made without departing from the scope of the appended claims.

Claims

1. Electromechanical apparatus (1) for establishing/interrupting a connection with telephone electrical conductors made of metal, comprising:

- a base body (3) on which a main printed circuit board (7) is mounted, along two opposed sides of which there are provided a series of first switching blades (11a) and a series of second switching blades (l ib), respectively;

- a selecting device (13) mounted on said main printed circuit board (7) between said series of first switching blades (11a) and said series of second switching blades (l ib);

- a closing cover (5), along two opposed sides of which there are provided a series of first contact pads (37a) and a series of second contact pads (37b), arranged in such a way that said first and second contact pads (37a,37b) are overlapped and aligned with said first and second switching blades (11a, l ib) when said closing cover (5) is mounted on said base body (3),

characterized in that said selecting device comprises a carriage (17) slidingly mounted between said series of first switching blades (11a) and said series of second switching blades (l ib) and at least one actuator (29a,29b) mounted in a seat provided at one side of said carriage (17), wherein said actuator (29a,29b) can be driven for being moved from a first position in which it does not interact with said switching blades (1 la, 1 lb) to a second position in which it acts upon one of said switching blades (11 a, l ib) for bringing said blade from a resting position in which said blade is in contact with said main printed circuit board (7) to a switching position in which said blade is in contact with the corresponding contact pad (37a,37b).

2. Electromechanical device (1) according to claim 1 , wherein said selecting device comprises a carriage (17) slidingly mounted between said series of first switching blades (11a) and said series of second switching blades (l ib) and a pair of actuators (29a,29b) mounted in seats provided at each side of said carriage (17), each of said actuators (29a,29b) being capable of being driven for being moved from a first position in which it does not interact with said switching blades (1 la, 1 lb) to a second position in which it acts upon one of said switching blades (1 la, 1 lb) for moving said blade from a resting position in which said blade is in contact with said main printed circuit board (7) to a switching position in which said blade is in contact with the corresponding contact pad (37a,37b).

3. Electromechanical apparatus (1) according to claim 2, wherein said actuators (29a,29b) are synchronously driven for being moved from said first position to said second position.

4. Electromechanical apparatus (1) according to claim 2, wherein said actuators (29a,29b) are driven separately and independently from each other for being moved from said first position to said second position.

5. Electromechanical apparatus (1) according to any of claims 1 to 4, wherein said selecting device (13) comprises a main axis (15) along which said carriage (17) slides and a pair of secondary axes (25a,25b) arranged each at a side of said main axis (15) and oriented in a direction essentially parallel to said axis, each of said actuators being fitted on a corresponding secondary axis (25a,25b).

6. Electromechanical apparatus (1) according to claim 5, wherein said secondary axes (15a,15b) and said actuators (29a,9b) are configured so that said secondary axes (25a,25b) drive said actuators (29a,29b) for moving them from said first position to said second position.

7. Electromechanical apparatus (1) according to claim 5 or 6, wherein said actuators (29a,29b) are cams fitted on said secondary axes (25a,25b).

8. Electromechanical apparatus (1) according to claim 5 or 6, wherein said actuators (29a,29b) are bushings fitted on said secondary axes (25a,25b) and provided with a peripheral finger (41a).

9. Electromechanical apparatus (1) according to any of claims 1 to 8, wherein said switching blades (1 1a) are configured so as to define an abutment surface (49a) for said actuator (29a), said surface being oriented so as to be parallel to the surface of said actuator when said actuator comes into contact with said switching blade (11a).

10. Electromechanical apparatus (1) according to claim 9, wherein in said switching blades said abutment surface (49a) is joined to the point of contact with said corresponding contact pad (37a) by means of a portion (51a) which is oriented in parallel with the direction of the force exerted by said actuator (29a) on said switching blade (11a) when said switching blade is moved to said switching position.