Abstract:
A position switch whose box houses a switch assembly that can be maneuvered by an activation head holding a push button and located in a recess on one surface of the box so that it can be angularly adjusted at regular intervals. The head has a tubular bearing surface facing the box and in which a plunger slides for actuating the switch assembly. The bearing surface has notches at regular intervals for alignment with corresponding notches in the box recess. A lockable fork retains the head in position.

Description:
BACKGROUND OF THE INVENTION 
     This invention concerns a switch, more specifically a position switch, comprising a box housing a device that can be moved in travel and an electric switch assembly activated by this device. Its manoeuvre head is fitted so that it is removable and angularly variable in a recess of the box, which opens out onto a fitting surface of the box. The manoeuvre head has a tubular bearing surface that houses a push button, directly or indirectly activated by an object, and able to slide along the travel axis to operate with the movable device. 
     It is often desirable to be able to adjust the position of the manoeuvre head of such a switch. Such adjustment may indeed be necessary if the switch is mounted in a pre-determined position, while accepting activation by moving objects with varying trajectories. 
     In most examples of this type of position switch, see for example the U.S. Pat. No. 3,590,177 document, the head has a turning part that is moved by a lever and push button activated by the rotating part to operate with the movable device. The angular position of the head is adjusted by means of a costly rack-and-pinion device. There are also position switches whose push button is controlled by an axial activator; thus, document FR 2 785 985 shows a position switch whose head can be angularly adjusted using an indexing coupling and a positioning washer. 
     It is also known—see document IT 218 310—how to adjust the angular position of an idle position switch lever, by providing teeth in an axial recess of the lever or a part fixed to the lever and additional teeth on the bearing surface of the turning part of the head. However, this does not enable positive adjustment of the angular position of the head. 
     The invention aims to provide great flexibility of use for a switch in a very simple and compact way, particularly a position or safety switch, by positive angular adjustment of the manoeuvre head. 
     According to the invention, the tubular bearing surface of the manoeuvre head is equipped with external notches, placed at regular intervals, 
     the outside of the box recess has internal notches, operating with the notches on the head, at the same intervals or at multiple intervals, 
     the external and internal notches fit together according to the translation axis of the moveable device. 
     The tubular bearing surface may also provide a stop shoulder applicable to the fitting surface, with the external notches of the tubular bearing surface below the shoulder and radially set back from it. The internal notches of the recess can be formed by a moulded toothed crown, located at the opening of the recess or added within the recess. 
     A fork used to fix the head axially and confirm engaging of the notches can be included in a slot of the box to operate with an annular groove on the tubular bearing surface of the head. The fork can be held in its fixture position by various holding means, particularly a lock. Marks provided on the branch of the manoeuvre head, which is directed along the translation axis, and on the upper fitting surface on the edge of the recess enable easy viewing of the angular position of the head. 
     The invention also concerns a pivoting lever position switch, offering double angular adjustment of the head in relation to the box, and of a pivoting manoeuvre lever in relation to the head. In this case, the head is an L-shape, with the two branches equipped with regularly spaced notches, the head being mounted by its first branch in the respective notches provided at regular intervals around the outside of the recess, the lever being mounted on the second branch of the head and having respective notches at regular intervals. 
     The description given below is of a non-limiting production method of the invention, supported by the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective drawing of the position switch according to the invention. 
     FIG. 2 shows a perspective exploded view on a larger scale of the switch in FIG.  1 . 
     FIG. 3 is a cross-sectional view of the top part of the switch. 
     FIG. 4 shows a perspective view of the top part of a production variation of the switch. 
     FIGS. 5 and 6 show the manoeuvre head blocking fork in the locked and unlocked positions respectively. 
    
    
     DETAILED DESCRIPTION 
     The position switch comprises a box  10 , equipped in its top part  10   a  with a manoeuvre head  20  and in its bottom part  10   b , with a cabling connector  11 . The overall box is approximately parallelepiped and comprises a body that is closed by a front cover, and houses an electric switch assembly  12 , to which the connector  11  is connected. A device  13  is mounted so that it can move in travel in the box, along axis X 1  to activate the switch assembly  12  in response to movement of a lever  30  mounted to rotate on the head  20  around an axis X 2  perpendicular to X 1 . 
     It should be noted that the cabling connector  11  is placed so that it is removable and interchangeable in a corner of the bottom part  10   b  of the box, so that different types of connection and orientations of the cable  11   a  are possible. 
     The overall manoeuvre head  20  is L-shaped with one branch  20 X 2 , along axis X 2 , housing a turning part  21  with a cam  22  (see FIG. 3) and with the other branch  20 X 1 , along axis X 1  perpendicular to X 2 , having a push button  23  activated in the down direction by the cam  22  of part  21  and in the upward direction by a return spring  24 . At its bottom end, the branch  20 X 1  of the manoeuvre head  20  narrows down to a tubular bearing surface  25 , which fits into a recess  14  (see FIG.  4 ), opening out on a more or less flat surface  10   c  located in the top part  10   a  of the box. The bearing surface  25  has an annular groove  26  and a seal  27  to ensure tight mounting of the head in the recess  14 . It also has an annular stop shoulder  25   a , which pushes against the upper surface  10   c  of the box, this surface being flat or slightly curved. The shoulder pushes against the edge of the recess  14 . 
     A fork  15  operates with the annular groove  26 . The fork forms a key that prevents extraction of the head in direction X 1 . The fork  15  is inserted from the front F into a slot  16  provided on the front of the box (see FIG.  6 ). The fork is shown on FIG. 1 in the position where the head  20  is blocked and on FIG. 2 in the position where the head is free (the head can then be extracted along X 1 ). It is pushed as shown by arrow F to move from its free position to its blocked position. 
     In its blocked position, the fork  15  can be locked by a pivoting lock  40 . The lock  40  is shown on FIG. 6, out of the box, to simplify comprehension. The lock  40  has a blocking tab  41  applicable against the apparent edge  15   a  of the fork to block it; the lock also has an eyelet or a lug  42  fixed to the tab  41 . The eyelet  42  is housed in a cylindrical housing  10   d  in the box  10  so that it can pivot around the housing axis and can be locked in position by a screw  43  whose head fits in the housing  10   d . Incidentally, the use of the screw to fix the box on a support (not shown) is well known. The lock  40  is a simple cut and folded metal part and is practically flush to the edge of the box, apart from the thickness of its plate, to enable easy manoeuvre. The lock pivots around the axis of the indentation to pass from its unlocked position (FIGS. 2 and 6) to its locked position (FIGS. 1 and 5) and vice versa. Lock movement is guided by operation of a claw  44 , provided on a right-angled extension of the tab  41 , with a split  10   e  in the top part  10   a  of the box. 
     The branch  20 X 1  of the manoeuvre head  20  can be fitted around its outside with external notches or teeth C 1  placed at small and regular intervals to enable fine adjustment of the angular position of the head. The notches can then connect with a small number of additional internal notches C 2  (such as four), but with the same interval, or a multiple interval, on part of the circular sector of the opening of the recess  14 . The notches have a small radial extension and their meshing is by engagement in direction X 1 . It is preferable that a small number of C 1  notches are provided (for example, two groups of four notches, opposite at 180°) on the connector  25 , while notches C 2  are provided in a ring all around the edge of the recess  14  at the immediate opening of this recess on the surface. As shown in FIG. 3, the notches C 1  are set back from the external template of the branch  20 X 1  of the head. It is also possible to provide only a few C 2  notches and C 1  notches around the whole periphery of the connector  25 . The interval is, for example, 15°. 
     The lever  30  usually has at its free end, a roller  30   a  against which the object manoeuvring the switch comes to a stop. It is fixed by a screw  31  along axis X 2  to the turning part  21 . The lever  30  has a hole  32  along axis X 2  so that it engages on a cylindrical bearing surface  28  of the turning part  21  so that it is angularly adjustable using indexing notches. For this purpose, around the edge of hole  32 , near part  21 , the lever  30  has internal notches C 3  spaced out at regular intervals, equal to the intervals of notches C 1 , C 2  or different from this interval, and part  21  has external notches C 4  of the same interval as the C 3  notches or of multiple interval, on bearing surface  28 . The lever  30  and the bearing surface  28  are made of resistant materials so that the teeth C 3 ,C 4  can withstand the forces transmitted by the lever. 
     Marks M 1 ,M 2  are provided on the head and on the upper surface  10   c  of the box to indicate the angular position of the head in relation to the box; marks can be provided on the lever and the turning part to indicate the angular position of the idle lever. 
     In the production variation shown in FIG. 4, the head of the position switch does not have a lever, but just a push button  50 , with a small number of notches C 1  (for example, four) at the top of its tubular connector  25 , while the recess  14  of the box  10  has a ring of C 2  notches around its perimeter  17  near its opening and on the inside. It is advantageous to make the ring during box moulding, but it can also be added in the recess  14 . 
     Adjustment is easy by releasing the lock  40 , then taking out the fork to bring it to the position indicated in FIGS.  2 , 4 , 6 , extraction of the head along X 1  to disengage the notches C 1 ,C 2 , placing of the head in the angular position required, pushing the head in along X 1  until the notches C 1 ,C 2  are engaged and the shoulder  25   a  comes to a stop against the tubular bearing surface  25  on the surface  10   c  of the box. It should be noted that no screws are required to fix and hold the head in the desired angular position. Adjustment is simplified by the presence of a small number of notches C 1  and the marks M 1 ,M 2 .