Abstract:
A latch mechanism for producing a releasable connection of a housing portion with a further housing portion provides projections on one of the housing portions, and for producing a releasable connection by means of a rotational motion of the housing portions relative to one another, the latch projections latchingly engaging in associated latch recesses, where the latching mechanism includes a rotatably mounted ring element including the recesses for receiving the projections. The latching mechanism can be connected by means of further latch recesses and further latch projections to the further housing portion.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This is a Continuation of International Patent Application PCT/EP02/04569 filed 25 Apr. 2002, which claims priority of German Patent Application 101 21 439.1 filed 27 Apr. 2001. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON COMPACT DISC 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a latch mechanism for producing a releasable connection of a housing portion with a further housing portion, projections being provided on one of the housing portions, and for producing a releasable connection by means of a rotational motion of the housing portions relative to one another, the latch projections latchingly engaging in associated latch recesses. 
   2. Description of Related Art Including Information Discussed Under 37 CFR 1.97 and 1.98 
   From U.S. Pat. No. 4,600,277, a telescope is known with a main housing and at least two interchangeable monocular systems. The two monocular systems differ definitively in that a first monocular system has a coaxial arrangement or alignment with respect to the optical axis of the telescope. A second monocular system has an angular shape and permits looking into the telescope at an angle of 45° to the optical axis, which is established by the lenses mounted in the main housing. The monocular arrangements can be connected to the main housing or to the telescope, respectively, by means of a bayonet coupling means. The bayonet coupling means includes L-shaped projections on the monocular system. These projections are fixedly connected to the housing of the respective monocular system and have an axial alignment in relation to the optical axis. Recesses are allocated to these projections, and are formed in a plate fixedly connected to the main housing and arranged at right angles to the optical axis of the telescope. The projections and the recesses have different extensions in the peripheral direction in comparison with each other, so that the monocular system can assume only a predetermined and thus defined position when the monocular system and main housing are connected. 
   For connecting the main housing and the monocular system, the projections are guided in an axial direction through the recesses formed in the plate. The L-shaped projections then clamp behind this plate by means of a rotational motion. For fixing, a pin is provided which latches into a recess provided in the monocular system. To release the monocular system, this pin, which is prestressed by a spring, has to be withdrawn by the user. For this, an operating element is provided which is to be operated by the user for this purpose. 
   From U.S. Pat. No. 2,260,991, a latch mechanism is known for providing a releasable connection of an objective with a camera housing. In this latch mechanism also, a plate fixed to the camera housing is provided. Recesses are provided in this plate with different extensions in the peripheral direction. Projections facing radially, formed on the objective housing, cooperate with these recesses when producing a fixed connection. To produce the fixed connection, the projections pass through the recesses of the plate connected to the camera. By rotation of the objective, the projections of the objective clamp behind the plate. 
   In these systems, it is disadvantageous that the projections formed on a component are strongly loaded when latching into the other component such as a main housing or camera housing. On frequent connection and release, damage of the projections results due to this strong loading. 
   SUMMARY OF THE INVENTION 
   The invention has as its object to further develop a releasable connection so that the loading on the projections provided for producing the connection is diminished. 
   The object of the invention is attained by a latching mechanism that includes a rotatably mounted ring element comprising recesses for receiving the projections; the latching mechanism being connectable by means of further latch recesses and further latch projections to the further housing portion. By the measure of providing a latch mechanism with a rotatably mounted ring element which has recesses to receive the projections, the releasable connection being provided by means of the ring element, the loading acting on the projections could be reduced, since the projections are received by the recesses on executing the rotary motion. 
   The projections can be introduced without force, or nearly without force, into the recesses formed in the ring element. On executing the rotary motion for producing the fixed connection of the ring element with the other housing portion, the connection is produced by means of the ring element and thus the loading to which the projections are subjected is strongly reduced. 
   It has been found to be advantageous to allocate at least one spring element to, and cooperating with, the ring element, so that the stress energy 
   of this spring element becomes free when the fixed connection of the housing portions is produced. 
   It has been found to be advantageous that on relieving the spring element, at least one of the provided latch projections latches into an associated latch groove. The ring element is thereby fixed against rotation. Positive locking is produced by the latching of the latch projections into the latch grooves. These latch projections and latch grooves can be arranged with radial alignment or else with axial alignment. 
   With radial alignment, it has been found to be advantageous to allocate respectively two diametrically opposite spring elements, so that the coaxial position of the ring element with respect to the optical axis is maintained. A coaxial arrangement of the housing portion connected to the ring element by means of the projections can easily be provided thereby. No decentering of the housing portions on releasing the housing portions must be taken into account. This has an advantageous effect when testing tolerances of the components. In particular, whether the projections have a symmetrical arrangement with respect to the optical axis can easily be tested. 
   It has been found to be advantageous that the ring element executes a motion in the axial direction when the spring element(s) is/are relieved, the axial direction being established by the optical axis. With such an arrangement, it can also be provided that the ring element executes a tilting motion for the production of latching. This can in particular occur when only one spring element is provided. 
   It has been found to be advantageous to provide plural spring elements acting axially parallel. A motion of the ring element parallel to the optical axis on releasing, or also on producing, the latching can be provided particularly easily by the provision of two or more spring elements. 
   It has been found to be advantageous that the ring element of the latching mechanism never gives a truly axial arrangement, both on releasing and also on producing the connection. 
   It has been found to be advantageous that the latch projection is simultaneously formed by means of the spring element. On latching of the spring element, stress energy becomes free, in that the spring element latches into the latch groove. This contributes to a particularly simple construction of a latching mechanism. 
   It has been found to be advantageous to provide leaf springs, which are inexpensively obtainable and function reliably, as the spring elements. 
   It has been found to be advantageous to place the spring elements so that the moment required for producing the releasable connection is greater than the moment which has to be applied to produce the connection. Inadvertent release is thereby countered. 
   It has been found to be advantageous to provide main springs by means of which axial play of the housing portions with respect to one another is compensated. In particular, if optical elements re arranged in the housing portions, an axial play can result which presents the user with an unsharp image. 
   This latch mechanism has been found to be particularly suitable for connecting optical components, particularly an eyepiece and an optical device. 
   This latch mechanism is particularly suitable for telescopes with interchangeable eyepieces, so that changing the eyepiece is easily performed and functions reliably. In particular, it is not necessary to operate a separate lever, which would act negatively on handling when changing the eyepiece. Release with this latching mechanism can be produced by solely moving the housing portions, particularly eyepiece and housing, relative to each other. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Further advantageous measures are described in the specific and claims. The invention is described using the following embodiment: 
       FIG. 1  shows a telescope; 
       FIG. 2  shows a latching mechanism; and 
       FIG. 3  shows an enlarged illustration of the latch mechanism being engaged; 
       FIG. 4  shows a diagram of projections received in the ring element. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A telescope with an axial monocular is shown in  FIG. 1 ; the invention is described in detail with reference thereto. 
   The telescope  1  comprises an objective  5 , an eyepiece  3 , and two housing portions  7 ,  9 . In this embodiment, the objective  5  is fixedly connected to the housing portion  7 , and the eyepiece is releasably connected to the housing portion  9 . The housing portions  7  and  9  are in their turn fixedly connected together. Furthermore, the telescope  1  has a grip region  13  in which grip grooves  15  are formed on both longitudinal sides. A stand fastening  11  is provided for connection to a stand. The telescope can be focused by means of a fine drive  19  and a coarse drive  17 . 
   The releasable connection between the housing portion  9  and the eyepiece  3 , or respectively a housing  4  of the eyepiece, is described in detail using  FIG. 2 . The housing  4  of the eyepiece  3  is arranged coaxially of an optical axis which is established by the optical lenses, not shown, provided in the eyepiece  3 . On the side to be connected to the housing portion  9 , the eyepiece  3  has an extension  23 . The extension is provided at its ends with projections  25 . These projections  25  have different shapes, here different extension in the peripheral direction. However, a different extension of the projections in the radial direction, or respectively solely a different shape of the projections, such as diamond-shaped, annular segment, etc., can however be provided. A seating  35  is arranged in the housing portion  9  of the telescope  1 . This seating  35  comprises a cover  73 , a ring element  57 , and a sleeve  29 . The cover  73  is provided with a closure plate  75  which is transparent and by means of which an internal volume of the telescope is sealed from the exterior. In particular, it can be ensured by means of the cover  73  with closure plate  75  that no moisture can penetrate into the volume formed by the housing portions  7 ,  9  and the objective. This internal volume is also thereby protected from dirt particles, particularly dust. 
   The ring element  57  is rotatably mounted in the cover  73 . Guide slots  65  are formed on the radial outer circumference of the ring element  57  for rotatable mounting, and are arranged together with rods  62  arranged coaxially of the optical axis of the telescope  1 ; the rods  62  are arranged stationary, by fixed connection with the sleeve  29  in the embodiment example shown. A limitation  63  of the rotation of the ring element  57  is provided by cooperation of the rods  62  with the guide slots  65 . 
   This sleeve  29  is fixedly connected to the cover  73 , so that the ring element  57  arranged between these can be moved to a limited extent between the sleeve  29  and the cover  73 . 
   The ring element  57  is provided with leaf springs  69 , fixedly connected by screws  71  to the ring element, on the side facing the cover  73 . The spring force of the leaf springs  69  acts in the axial direction. In the assembled state, the leaf springs  69  are supported against the cover  73 . The ring element  57  is provided on the opposite side with latch projections  59 , which are arranged aligned in the axial direction. At least one latch projection  59  has a ramp  60  directed peripherally. If the latch projections  59  are received by the latch grooves  51 , it is ensured by means of the ramp  60  that the ring element  57  simultaneously executes a movement in the axial direction upon rotation of the ring element, due to the ramp  60  cooperating with the latch grooves  51 . The ramp  60  can also be formed on the latch grooves  51 . The spring elements  67 , or respectively the leaf springs  69 , are simultaneously prestressed when the latch projections  59  come out of the latch grooves  51 . To reduce the surface pressing of the latch groove  51  and latch projection  59  per surface segment, preferably both are formed with a ramp  60 , which is provided on the surfaces cooperating when releasing the connection. If the spring elements  67  are prestressed, the latch projections  59  are connected to the contact regions  55  formed on the sleeve  29 , or respectively are supported on this. These contact regions  55  are formed by axial projections  53  which are integrally formed with the sleeve  29 . These contact regions are arranged bordering on the latch grooves  51  in the peripheral direction. 
   If the leaf springs  69  also function as latch projections (not shown), the leaf springs provided could be arranged instead of the latch projections, and the ring element would be in sliding contact with the cover on the opposite side. Latch projections and latch grooves could of course be provided on the cover side, and the ring element would then be in sliding connection with the sleeve. 
   The spring elements prestressed when the latch mechanism is released give rise to contact friction arising on rotation of the ring element  57 , ensuring that unintentional rotation of the ring element does not occur. This is particularly advantageous on inserting the projections  25  into the recesses  58  formed in the ring element  57 . The recesses  58  are arranged aligned tangentially on the inner side of the ring element. 
   The sleeve  29  is provided with main springs  41  on the side facing the ring element  57 . The spring force of the main springs acts in the axial direction. As main springs  41  in this embodiment example, leaf springs  43  are fixedly connected to the sleeve  29  by fastening elements, here screws  47 . Recesses  49  for providing a possible spring path for the main springs  41  are formed under the leaf springs. The sleeve  29  has a radial profile  31  at the external periphery. This radial profile  31  comprises two annular projections. This profile acts to produce the fixed connection of the cover  73  and sleeve  29 . 
   A joint ring  33  is provided on the side of the sleeve  29  facing the eyepiece  3  and, together with the groove formed running around the eyepiece  3 , a stop  27  is formed thereby. 
   The eyepiece has an extension  23  on the side facing the sleeve  29  and aligned coaxially of the optical axis  20 . If the eyepiece is fixedly connected to the telescope, the sleeve  29  and also the ring element  57  are arranged coaxially of the extension  23 . The mounting of this extension  23  within the sleeve  29 , with the ring element  57  rotatably mounted on the extension, is shown in  FIG. 4 . The projections  25  are formed at the end on the side of the extension  23  facing the sleeve  29 . 
   To join the eyepiece  3  to the telescope  1 , the extension  23  is inserted into the sleeve  29 , the projection  25  being received by the recesses  58 . By rotating the housing  4  of the eyepiece  3  relative to the housing portion  9 , the ring element  57  is also rotated relative to the cover  73  and the sleeve  29 . Upon reaching the latching position provided, the latch projections  59  engage in latch grooves  51 . The ring element  57 , started by the spring elements  67 , then moves in the axial direction, upon which the spring elements relax. 
   With the arrangement of the latch projections and latch grooves in the radial direction (not shown), the spring element is to be arranged such that the spring force of the spring elements also acts in the radial direction, so that the stress energy of the spring elements is released upon latching.