Abstract:
A light-emitting device to detect passage or smoke in the emitted beam. The device includes a source of invisible radiation, a source of visible laser radiation, an alignment component to align the central axis of the visible radiation with an axis parallel to the central axis of the invisible radiation, and a switch to turn off the visible laser source. The device can further include a housing containing both sources of radiation. The switch is configured to be controlled by the closing of the housing and the source of visible laser radiation is turned off in response to the closure of the housing.

Description:
RELATED APPLICATIONS 
     This application is a §371 application from PCT/FR2013/053284 filed Dec. 30, 2013, which claims priority from French Patent Application No. 12 62905 filed Dec. 28, 2012, each of which is herein incorporated by reference in its entirety. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a light-emitting device for detecting passage or smoke, a method for manufacturing such a device and a passage and smoke detection device comprising same. It applies, in particular, to fire and/or intrusion detection and/or to the surveillance of premises or sites. 
     STATE OF THE ART 
     Fire detection is realized in many different ways, at least one of which is optical. In this case, a light signal is emitted in the premises, preferably infrared for smoke detection, the light radiation emitted is received after it has passed through a portion of the atmosphere in the premises, and the presence of smoke is detected when the amount of light received is below a limit value. The greater the distance traversed by the light ray, the faster the smoke detection. However, the orientation tolerances of the light emitting components are large and inserting these detectors in housings adds an additional dispersion. Thus, it is difficult to correctly position the light sensor facing the light emitter or, in the case where a single housing comprises the emitter and the sensor, to position a retro-reflector in the emitted light beam. Consequently, either the distance traversed is reduced or the installation takes a long time. 
     Preventing the risk of a third-party intrusion or fire in premises or sites is a significant constraint for the security of the property and persons present inside said sites and premises. The known detection systems use either cameras or sensors of light rays emitted by light sources. The cameras and image processing required to detect the passage of an intruder are complex, expensive and not very reliable, because they are sensitive to the movement of shadows, e.g. of trees set in movement by the wind or birds. In addition, the light rays to be used must be invisible to prevent intruders from seeing them and therefore from bypassing them or, in the case of fire detection, to be as nonintrusive as possible. However, aiming an invisible ray at a target turns out to be a very delicate operation, increasing the installation time of such systems. 
     OBJECT AND SUMMARY OF THE INVENTION 
     The present invention aims to remedy all or part of these drawbacks. 
     To this end, according to a first aspect, the present invention envisages a light-emitting device for detecting passages through the emitted beam, that comprises:
         a source of visible laser radiation;   a means for aligning the central axis of the visible radiation with a reference axis parallel to the central axis of the invisible radiation; and   a switch to switch the visible laser source off.       

     Thanks to these provisions, while a passage detection system is being installed, the light-emitting device is installed by lighting the source of visible laser radiation. Aiming the laser at a target, e.g. a light sensor or a retro-reflector, is therefore easy, since the operator can see the visible laser radiation. 
     In some embodiments, the source of visible laser radiation emits a light with a wavelength of between 497 and 560 nm. These provisions make the laser radiation particularly visible. 
     In some embodiments, the device that is the subject of the present invention comprises a means of controlling a cyclical lighting of the visible laser source downstream from the switch. 
     Thanks to these provisions, the visible laser ray is all the more visible, since the operator&#39;s eyes see changes in luminosity better than constant light. In addition, the electrical consumption of the device is decreased because, during the installation, the source of visible laser radiation is only lit for a portion of the lighting cycle. 
     In some embodiments, the device that is the subject of the present invention comprises a housing that contains the two radiation sources and a switch, the switch for switching off the visible laser source being controlled by the switch of the housing, configured to control the activation of the visible laser source when the housing is opened and instructing the source of visible laser radiation to be switched off when the housing is closed. 
     Thanks to these provisions, during installation, the housing is open and aiming the radiations at the targets is performed with the aiming means contained in the housing. In contrast, when the aiming has been performed, the housing is closed, which has the effect of switching off the source of visible laser radiation and of protecting the aiming means from any handling. 
     In some embodiments, the source of visible laser radiation has an outer cylindrical or conical surface of revolution and a predefined angular tolerance, and the alignment means comprises:
         an outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance; and   an intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part and an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the source of visible laser radiation, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle.       

     Thanks to these provisions, once both laser radiation sources have been installed on a flat mounting, in-factory, their optical axes are adjusted to be parallel by turning the intermediate part and the source of visible laser radiation, causing the orientation of the optical axis of the source of visible laser radiation to vary in a continual and regular manner. 
     In some embodiments, the source of invisible radiation has an outer cylindrical or conical surface of revolution and a predefined angular tolerance, and the alignment means comprises:
         an outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance; and   an intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part and an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the source of invisible radiation, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle.       

     Thanks to these provisions, once both laser radiation sources have been installed on a flat mounting, in-factory, their optical axes are adjusted to be parallel by turning the intermediate part and the source of invisible radiation, causing the orientation of the optical axis of the source of visible laser radiation to vary in a continual and regular manner. 
     In some embodiments, the mount of the source of visible laser radiation comprises at least one outer part comprising a cylindrical recess and an inner part, whose outer surface matches the recess of the outer part, having a cylindrical recess with a circular base matching the outer surface of the source of visible laser radiation, the axes of the inner and outer cylindrical surfaces of the inner part forming an angle between them greater than one angular degree and less than ten angular degrees. 
     Thanks to these features, by causing the inner cylinder to turn inside the outer cylinder and the source of visible laser radiation inside the inner cylinder, any difference between the mechanical and optical axes of the source of visible radiation can be compensated, within a solid angle. Thus sources of visible radiation with large manufacturing tolerances and, therefore, low cost prices can be used. 
     According to a second aspect, the present invention envisages an alarm device that comprises a light-emitting device that is the subject of the present invention, a means of receiving the light emitted by said light-emitting device, and a means of generating alarms configured so as to emit an alarm signal when the light reception means receives a light intensity lower than a predefined limit value. 
     According to a second aspect, the present invention envisages smoke detection device that comprises a light-emitting device that is the subject of the present invention, a means of receiving the light emitted by said light-emitting device, and a means of generating a signal representative of the detection of smoke configured so as to emit a smoke detection signal when the light reception means receives a light intensity lower than a predefined limit value. 
     According to a third aspect, the present invention envisages an intrusion detection device that comprises a light-emitting device that is the subject of the present invention, a means of receiving the light emitted by said light-emitting device, and a means of generating a signal representative of the detection of intrusions configured so as to emit an intrusion detection signal when the light reception means receives a light intensity lower than a predefined limit value. 
     According to a fourth aspect, the present invention envisages a manufacturing method for a light-emitting device that is the subject of the present invention, that comprises:
         a step of installing the source of invisible radiation on a flat mounting;   a step of installing the source of visible laser radiation on the flat mounting; and   a step of aligning the optical axes of the laser radiation sources to be parallel.       

     In some embodiments, during the step of parallel alignment, the following are carried out:
         a step of rotation, in an outer part comprising a cylindrical recess, of an inner part, whose outer surface matches the recess of the outer part, having a cylindrical recess with a circular base matching the outer surface of the source of visible laser radiation, the axes of the inner and outer cylindrical surfaces of the inner part forming an angle between them greater than one angular degree and less than ten angular degrees and   a step of rotating the source of visible laser radiation within the inner part.       

     In some embodiments, the source of visible laser radiation having an outer cylindrical or conical surface of revolution and a predefined angular tolerance, during the step of parallel alignment, the following are carried out:
         a step of rotation of an intermediate part within an outer part,
           the outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance and   the intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part; and   
           a rotation of the source of visible laser radiation within the intermediate part,
           the intermediate part having an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the source of visible laser radiation, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle.   
               

     In some embodiments, the source of invisible radiation having an outer cylindrical or conical surface of revolution and a predefined angular tolerance, during the step of parallel alignment, the following are carried out:
         a step of rotation of an intermediate part within an outer part,
           the outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance and   the intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part; and   
           a rotation of the source of invisible radiation within the intermediate part,       

     the intermediate part having an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the source of invisible radiation, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle. 
     As the particular characteristics, advantages and aims of these detection devices and of this method are similar to those of the light-emitting device that is the subject of the present invention, they are not repeated here. 
     Another problem that is solved by some embodiments of the present invention is that of the alignment of an axis of a mechanical part parallel to a predefined axis, when said axis of the mechanical part has an angular tolerance. 
     For example, the mechanical part is a light source, whose optical axis, which has an angular tolerance in relation to the mechanical axis, must be aligned parallel to an optical axis. 
     To remedy this parallel alignment difficulty, the present invention envisages, according to a fifth aspect, a device for aligning parallel to a reference axis a part having an outer cylindrical or conical surface of revolution and a predefined angular tolerance, that comprises:
         an outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance; and   an intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part and an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the part whose axis is to be aligned, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle,
 
the part whose axis is to be aligned sliding in rotation in the inner hole of the intermediate part.
       

     It should be noted that two “matching” surfaces means two surfaces identical to within mechanical play, which allows the rotation of one surface within another. 
     Thanks to these provisions, by performing a rotation of the intermediate part within the outer part and a rotation of the part whose axis is to be aligned within the intermediate part, any angle, below the angular tolerance, of the axis to be aligned to the mechanical axis of the part can be compensated. 
     In some embodiments, the first angle is at least equal to the sum of half the predefined angular tolerance and the mechanical positioning angular tolerance of the axis of the outer part. 
     Thanks to these provisions, even if the outer part has an axis offset, within the positioning tolerance limit, in relation to its nominal position, the alignment can be realized. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other advantages, aims and characteristics of the present invention will become apparent from the description that will follow, made, as an example that is in no way limiting, with reference to the drawings included in an appendix, wherein: 
         FIG. 1  represents, in four cross-section views, elements of a particular embodiment of the light-emitting device that is the subject of the present invention; 
         FIG. 2  represents an installation diagram of an alarm device that is the subject of the present invention; 
         FIG. 3  represents, in the form of a logical diagram, steps utilized in a particular embodiment of the method that is the subject of the present invention; 
         FIGS. 4 to 6  represent respectively two parts of a means for aligning optical axes and a source of visible laser radiation; and 
         FIGS. 7 to 9  represent respective successive positioning of the parts illustrated in  FIGS. 4 to 6  and of the source of visible laser radiation. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Note that the figures are not to scale. 
       FIG. 1  shows a particular embodiment of a light-emitting device  10  that is the subject of the present invention, excluding the housing, in a front view at top left, in a cross-section along axis A-A, at bottom-left, and in cross-section along axis B-B at right, and, for a housing, at bottom-right. 
     This device  10  comprises:
         a source  110  of invisible radiation;   a source  115  of visible laser radiation;   a means  155  and  160  for aligning the central axis of the visible radiation with a reference axis parallel to the central axis of the invisible radiation; and   a switch  140  to switch the visible laser source  115  off.       

     In this device  10 , a flat mounting  105  holds the invisible light source  110 , the visible laser light source  115  and a photoreceptor  120 . Each of these photo-electronic components is surrounded by a cylinder  145  for protection against parasite light. The protection cylinders are made of a black plastic mechanical part fastened onto the flat mounting  105  with screws  125 . 
     The photoreceptor  120  has a chromatic filter  150  mounted on it, which is configured to let a narrow range of wavelengths around the emission wavelength of the source of invisible laser light  110  pass through. 
     The source of invisible light  110  is, for example, an infrared diode that emits within the infrared wavelength spectrum. The source of visible laser light  115  emits, preferably, a green light beam, a color to which the human eye is particularly sensitive. It is recalled here that primary green is visible within a wavelength range of approximately 497-560 nm. The sensitivity of a human eye accustomed to darkness is greater for a wavelength of approximately 507 nm, i.e. blueish-green, whereas an eye accustomed to light is more sensitive to a wavelength of 550-555 nm, i.e. yellowy-green. 
     The photoreceptor  120  is, for example, a phototransistor. In some variants, the source of invisible light  110  is an infrared laser diode. 
     A switch  140  allows the source of visible laser light  115  to be switched on. A cyclical means of control  135  is positioned between the switch  140  and the source of invisible light  115 . When the housing of the device  10  is open and the switch  140  is closed, the source of visible laser light  115  consequently emits a visible light beam cyclically. For example, the duration of the cycle is one second and the duration of the light emission is one half-second. 
     A switch  130 , controlled by closing the housing, causes the light emission to switch between the source of visible laser light  115 , when the housing is open, and the source of visible laser light  110 , when the housing is closed. 
     To make the light rays coming from the two light sources  110  and  115  parallel, the device  10  comprises means of adjusting the orientation of the optical axis of the light source  115 . In the embodiment shown in  FIG. 1 , the source of invisible light  110  is a surface-mounted device (“SMD”). Its orientation is therefore fixed in relation to the flat mounting  105 . In contrast, the source of visible light  115  is a low-cost component shaped as a cylinder with a circular base. 
     The means for parallel alignment of the optical axes of the radiation sources  110  and  115  comprises, in the embodiment shown in  FIG. 1 , forming a base for the source of visible radiation  115 :
         an outer part  155  comprising a cylindrical recess and   an inner part  160 , whose outer surface matches the recess of the outer part, having a cylindrical recess with a circular base matching the outer surface of the source of visible laser radiation, the axes of the inner and outer cylindrical surfaces of the inner part forming an angle between them preferably greater than one angular degree and less than ten angular degrees, preferably less than five angular degrees.       

     The alignment means is described with reference to  FIGS. 4-9 . 
     In this way, by firstly making the inner part  160  turn within the cylindrical recess of the outer part  155  and, secondly, the source of visible laser radiation  115  turn in the inner recess of the inner part  160 , the optical axis of the source of visible laser radiation  115  is oriented to any direction of a solid angle. 
     In this way, the difference between the mechanical and optical axes of the source of visible radiation  115  is compensated. Thus sources of visible radiation with large manufacturing tolerances, e.g. of three angular degrees, and, therefore, low cost prices can be used. 
     Each device  10  is coupled to a reflector, e.g. a retro-reflector, positioned at one extremity of an optical path that corresponds to the optical axis of the source of invisible light  110 . The reflected light is partially captured by the photoreceptor  120 . The output signal of the photoreceptor  120  is processed by an electronic circuit (not shown but preferably coinciding with the flat mounting  105 ) that compares it to a predefined limit value. The limit value is either fixed or adaptive, i.e. slowly variable according to the output signal of the photoreceptor  120 . When the signal coming from the photoreceptor  120  corresponds to a reflected light intensity lower than a limit value, the electronic circuit triggers a signal representing the passage of an object, a person or an animal in the optical path that goes from the light source  110  to the reflective surface. 
       FIG. 1  shows, at bottom right, a cross-section of a housing cover  165 , comprising a window  170 , transparent to the wavelengths perceived by the photoreceptor  120 . 
     This housing  165  also comprises a pusher  175 , configured to operate the switch  130  when the housing on the flat mounting  105  is closed, so that the source of visible light  115  can no longer emit light and the source of invisible light  110  can emit light. Conversely, as soon as the housing  165  is open, the switch  130  is released and the source of visible light  115  can emit light and the source of invisible light  110  can no longer emit light. Of course, during the manufacturing and adjustment phase of the device, both sources of light can emit simultaneously, under the control of a program dedicated to this phase. 
     As can be seen in  FIG. 2 , to monitor a site by detecting intrusions, an alarm device  20  is installed, which comprises at least one light-emitting device that is the subject of the present invention. In  FIG. 2 , two light-emitting devices  205  and  210  are used. Firstly, the light-emitting device  205  emits a visible light ray  215  that is reflected on a retro-reflector  225 . The positioning of the device  205  and/or of the retro-reflector  225  is assisted by the fact that the light emitted by the source  115  is visible and by the fact that this light emission is intermittent. Once the positions of the device  205  and the retro-reflector  225  have been fixed, the housing of the device  205  is closed, which has the effect of switching off the source  115 . While it is in operation, the device  205  emits an invisible ray  220  that is also reflected on the retro-reflector  225 . 
     In the same way, the device  210  emits in succession a visible light ray  230  then an invisible light ray  235  in the direction of a retro-reflector  240 . After being compared to a predefined limit value, the signal coming from the photoreceptors  120  of the devices  205  and  210  are transmitted to an alarm control unit  245 . The alarm control unit  245  follows the commands of a program to trigger actions, following the detection of a passage in the light beams  220  and  235 . For example, the alarm control unit  245  makes telephone calls and/or triggers a sound alarm by causing a loudspeaker  250  to emit a sound signal. 
     In some embodiments, the device  20  is incorporated into a smoke- or fire-detection device, which also comprises a means of generating a signal representative of the detection of smoke configured so as to emit a smoke detection signal when the light reception means receives a light intensity lower than a predefined limit value. 
     In some embodiments, the device  20  is incorporated into an intrusion detection device, which also comprises a means of generating a signal representative of the detection of an intrusion configured so as to emit an intrusion detection signal when the light reception means receives a light intensity lower than a predefined limit value. 
     As can be seen in  FIG. 3 , manufacturing a light-emitting device that is the subject of the present invention comprises:
         a step  300  of installing the source of invisible radiation  115  and the source of visible laser radiation  110  onto a flat mounting and   a step  305  to  315  of aligning the parallelism of the axes of the laser radiation sources  110  and  115 .       

     During the step  305 , the source of invisible radiation  110  is switched on and it is checked that the direction of the optical axis of the source of invisible laser radiation  110  is perpendicular to the flat mounting  105 . If it is not, the orientation of the flat mounting  105  is changed until the optical axis of the source of invisible radiation  110  corresponds to a predefined optical axis. For example, a measurement is made of the radiation reflected onto the photoreceptor  120  for a first retro-reflector, which is positioned in the vicinity of the flat mounting  105 ; then, once the orientation has been adjusted, on a second more distant retro-reflector and so on. 
     It should be noted that, for certain laser diodes, the optical axis is normalized as perpendicular to the plane of the surface-mounted circuit (“SMC”) and step  305  is redundant. 
     During the step  310 , the source of visible laser radiation  115  is switched on and the parallelism of the optical radiation sources  110  and  115  is adjusted by carrying out the following:
         a step of rotation, in an outer part comprising a cylindrical recess, of an inner part, whose outer surface matches the recess of the outer part, having a cylindrical recess with a circular base matching the outer surface of the source of visible laser radiation, the axes of the inner and outer cylindrical surfaces of the inner part forming an angle between them greater than one angular degree and less than ten angular degrees and   a step of rotating the source of visible laser radiation within the inner part.       

     During the step  315 , the location of the source of visible laser radiation  115  is fixed, e.g. by welding or bonding. During a step  320 , the light-emitting device  10  is installed on the site to be monitored without placing the housing&#39;s cover over the flat mounting  105 . During a step  325 , the source of visible laser radiation  115  is switched on. 
     During a step  330 , the relative positioning of the device  10  and the retro-reflector, which is to reflect its invisible radiation, is realized. To achieve this, either the device  10  is held in place and the retro-reflector is positioned at the place specified by the visible laser radiation, or the retro-reflector is fixed beforehand, then the device  10  is moved or its orientation is modified. The change in the orientation of the device  10  is performed by utilizing adjustment screws configured to allow an adjustment of the angle, causing the alignment of the source  115  of visible laser radiation. 
     During a step  335 , the housing of the device  10  is closed by positioning the cover. During a step  340 , closing the housing of the device  10  causes the source of visible laser radiation  115  to be switched off. 
     During a step  345 , the site surveillance is triggered. This surveillance is triggered by the alarm control unit  245 . During a step  350 , the source of invisible radiation  110  is switched on. During a step  355 , the passage of an object, an animal, a person or a darkening due to smoke within the ray emitted by the source of invisible laser radiation is detected by processing the signal coming from the photoreceptor  120 . During a step  360 , if a passage is detected, the alarm control unit triggers actions according to the program that makes it work. 
     As illustrated in  FIG. 4 , the outer part  155  of the means for parallel alignment of the optical axes of the sources of radiation  110  and  115  has an inner cylindrical or conical hole of revolution  156 . In  FIG. 4 , this hole  156  is a tapered cylinder of revolution. 
     The axis of the hole  156  is offset in relation to the reference axis by a first angle at least equal to half the predefined angular tolerance of the source  115  of visible laser radiation. 
     Preferably, the first angle is at least equal to the sum of half the predefined angular tolerance and the mechanical positioning angular tolerance of the axis of the outer part  155  and of the mechanical positioning angular tolerance of the axis of the source of invisible radiation  110 . 
     As illustrated in  FIG. 5 , the intermediate part  160  of the alignment means has:
         an outer cylindrical or conical surface of revolution  162  matching a portion of the inner hole  156  of the outer part  155 ; and   an inner cylindrical or conical hole of revolution  161  (cylindrical in  FIG. 5 ) matching a portion of the outer surface  118  of the source  115  of visible laser radiation, the axis of the outer surface  161  and the axis of the inner hole  162  of the intermediate part  160  forming an angle between them preferably equal to the first angle.       

     As illustrated in  FIG. 6 , the source  115  of visible laser radiation has an outer cylindrical or conical surface of revolution  118  (cylindrical in  FIG. 6 ) and a predefined angular tolerance between its mechanical axis  117  (the axis of revolution of the outer surface  118 ) and its optical axis  116 , i.e. the axis along which the laser radiation travels. It should be noted that, if the source  115  of visible laser radiation does not have an outer cylindrical or conical surface of revolution, the source  115  is fixed to a part having these missing geometric characteristics. 
     To align the optical axis of the radiation source  115  and the axis of the source of invisible radiation  110  to be parallel, starting from the configuration illustrated in  FIG. 7 , during step  310 , the following are made to turn simultaneously or successively:
         the intermediate part  160  within the outer part  155  as illustrated in  FIG. 8 , and   the source of visible laser light  115  within the intermediate part  160 , as illustrated in  FIG. 9 .       

     It should be noted that the means of alignment shown with reference to  FIGS. 4 to 9  are applied, in variants, to the source  110  of invisible radiation or to each of the two sources of radiation  110  and  115 . 
     More generally, the characteristics of the alignment means illustrated in  FIGS. 4 to 9  make it possible to obtain the alignment of an axis of a mechanical part parallel to a predefined axis, when said axis of the mechanical part has an angular tolerance. 
     In the above example, the mechanical part is a light source, whose optical axis, which has an angular tolerance in relation to the mechanical axis, must be aligned parallel to a reference optical axis, i.e. the optical axis of the source of invisible radiation. 
     More generally, to remedy the difficulty of parallel alignment of two axes, the present invention envisages, according to a fifth aspect, a device for aligning parallel to a reference axis a part having an outer cylindrical or conical surface of revolution and a predefined angular tolerance, which comprises:
         an outer part having an inner cylindrical or conical hole of revolution, the axis of the hole being offset in relation to the reference axis, by a first angle at least equal to half the predefined angular tolerance; and   an intermediate part having an outer cylindrical or conical surface of revolution matching a portion of the inner hole of the outer part, and an inner cylindrical or conical hole of revolution matching a portion of the outer surface of the part whose axis is to be aligned, the axis of the outer surface and the axis of the inner hole of the intermediate part forming an angle between them equal to the first angle,
 
the part whose axis is to be aligned sliding in rotation in the inner hole of the intermediate part.
       

     It should be noted that two “matching” surfaces means two surfaces identical to within mechanical play, which allows the rotation of one surface within another. 
     Thanks to these provisions, by performing a rotation of the intermediate part within the outer part and a rotation of the part whose axis is to be aligned within the intermediate part, any angle, below the angular tolerance, of the axis to be aligned to the mechanical axis of the part can be compensated. 
     In some embodiments, the first angle is at least equal to the sum of half the predefined angular tolerance and the mechanical positioning angular tolerance of the axis of the outer part. 
     Thanks to these provisions, even if the outer part has an axis offset, within the positioning tolerance limit, in relation to its nominal position, the alignment can be realized.