Connection

A connection of two components is disclosed that abut on the faces thereof. With this connection, it is possible to create a stable connection, particularly of flat components, with a high level of precision of the position with regard to one another and with a preferred accessibility in the space around the plane extending from the adjacent adjoining faces of the components. Both components each have a half borehole with encircling collars; a fastening device that extends through the complete borehole and a nut having a conical recess which rests tightly against the collars so that the first component is fastened to the second component in a positive manner. It is further possible to provide a fastening of guiding elements to a middle base support that, in essence, overlaps the support at least occasionally and is effected by the connection.

BACKGROUND OF THE INVENTION

The invention relates to a housing for a printer of a motor vehicle tachograph, having a basic housing body and a support which is designed as an insert, can be moved at least partly out of the housing and has at least one guide which comprises at least two first guide elements which are arranged on and fastened to the support on two opposite sides, and two second guide elements which correspond to the first guide elements on the support are arranged on both sides of the support, with the result that the support is guided by means of the guide during a movement in or against an insertion direction.

New fastening techniques have been continually developed from time immemorial given the correspondingly wide range of possibilities of connecting two adjoining components to one another. In spite of the widely advanced development of the prior art, the known solutions have until now proved inadequate for specific fastening tasks. Reasons for this include the increasing requirements for compactness, automatability of the assembly and precision in the connection technique. Thus difficulties often arise during fully automated assembly sequences in interconnecting two adjoining components where there is poor accessibility with low positional tolerance. This is particularly the case when the accessibility of the connection is substantially only possible in the plane defined by the two boundary surfaces to be joined together. Recourse is frequently had in such a case to a flange connection. However, this has the disadvantage that bulky flanges have to be integrally formed on the components to be connected and corresponding arrangements enabling fastening elements to be applied have to be provided on these flanges. Moreover, such connections are also not suitable for fully automated assembly. This problem always arises when flat abutting components have to be firmly connected.

European patent application EP 1 052 514 Al has already disclosed a housing of the initially mentioned type, although this housing unfavorably transfers inaccuracies to the support guide, which leads to the print quality of the printing device described being impaired. A similar arrangement can also be taken from laid-open specification DE 198 07 332 A1, in which lateral guide rails form a constituent part of a U-shaped guide component which has to be designed to be deformable for assembly purposes, impairing the precision.

SUMMARY OF THE INVENTION

The invention is therefore based on the object of providing a connection which allows stable fastening of two adjoining components, in particular flat components, with a high degree of accuracy of the position with respect to one another and preferred accessibility in the space around the plane defined by the adjacent adjoining end faces of the components.

To achieve the object, the invention proposes a housing of the initially mentioned type having the features of claim1. The subclaims contain advantageous developments of the invention.

The socket expediently encompasses the collars provided on the two components, with the result that the fastening arrangement exclusively secures the first fastening element at the intended location, transverse forces and tensile forces are introduced into the first fastening element by the collars and are absorbed to a significant extent by said fastening element as tensile loading. The fastening arrangement experiences load relief and may accordingly be dimensioned sparingly. The connection according to the invention advantageously not only fastens the components to one another but also centers them with respect to one another. In particular, a relative movement in the plane defined by the boundary surfaces of the two components is prevented.

An advantageous development of the invention provides that the collar is designed to be conical on the outer circumference, with the result that a force which brings together the two half bores is produced when securing the fastening arrangement. The conicity of the collar or of the socket of the first component results in the fact that when securing the fastening arrangement the two adjoining components advantageously experience a respective force bringing them together. By virtue of the conicity, the socket in the first component does not have to be exactly matched to the shape of the collars of the two partial bores in order to produce a firm connection. Centering is produced in a particularly exact manner here because the connection is free from play in the secured state.

A cone angle of the socket or of the collars of about 45°+/−30° is particularly advantageous. A ratio of the length of the conical section to the diameter of the half bores of about 0.5+/−0.3 is expedient. A comparatively steep cone angle is recommended for a particularly firm fit.

The invention also relates to a fastening element for a connection of the above-described type, which comprises a basic body having a bore which is provided at least partially with an internal thread and the bore is widened conically without a thread in a first section on the entry side. The conical widening expediently has a cone angle of about 45°+/−30° and a depth in the bore of about 0.5+/−0.3 of the diameter. The fastening element, or first fastening element of the abovementioned connection, is expediently produced from metal material for high tensile loading.

To introduce a torque into the fastening element, it is appropriate if the basic body comprises arrangements, in particular flats disposed tangentially to the bore, for inserting a tool for introducing a torque into the basic body in the direction of the central axis of the bore.

The fastening element according to the invention advantageously combines a number of functions in one component. On the one hand, it assumes the function of a nut or else a screw in the conventional sense, for example for fastening the adjoining components to be connected to one another on a common base component, for example a housing wall, and, on the other hand, the two adjoining components are braced against one another and fastened to one another.

The aforementioned fastening element, or the first fastening element, is expediently complemented by a screw or a threaded bolt mounted on a base element, for example a threaded bolt mounted on a housing wall, to form the connection according to the invention.

The connection according to the invention, or the fastening element according to the invention, is particularly advantageously used in a housing, likewise forming the subject of the invention, in particular in the housing for a printer of a motor vehicle tachograph, having a support which is designed as an insert, can be moved at least partly out of the housing and has at least one guide which comprises at least two first guide elements which are arranged on the support and comprises two second guide elements which correspond to the first guide elements on the support, with the result that the support is guided by means of the guide during a movement in or against an insertion direction, the second guide elements being fastened to a central base support and substantially overlapping the support at least periodically. Instead of a hitherto customary fastening of the second guide elements to the housing, according to the invention the second guide elements are fastened to the central base support, with the result that the generally high inaccuracies of the housing have no effect on the position of the second guide elements. As regards the relative position of the two second guide elements with respect to one another, according to the invention only the accuracy of the central base support remains crucial.

A further advantage of the arrangement of a central base support according to the invention between the two second guide elements is provided upon assembly, during which all of the components directly connected to the central base support and to the second guide elements can first be assembled in a fully automated manner and form a unit which can be handled separately. These components can in this way also be tested independently of the overall arrangement.

It is appropriate for this purpose to provide the two second guide elements with suitable connection elements which, together with corresponding mating pieces on the central base support, ensure that none of the components can be lost. Latching or clip connections are highly suitable for this purpose, if appropriate in combination with preferably cylindrical or conical guides.

Such an arrangement is particularly expedient if a printer is arranged in the housing which comprises a media unit, which is fastened to the support, for receiving the medium which is to be printed on. The requirements for comfort when replacing the medium to be printed on require that the printer comprises a printing unit which is fastened to the base support.

Such a combination of support, base support, media unit, feed unit and printing unit results in the fact that the feed unit, which can be moved with respect to the static printing unit, has to be guided with high precision in order that the printed image is not unacceptably impaired in terms of quality as a result of incorrect positioning of the printing head with respect to the feed unit. The arrangement according to the invention of a central base support which substantially overlaps the support and on which the second guide elements are fastened is particularly high for the relative position of the printing unit with respect to the feed unit.

The combination of the connection according to the invention with the above-described arrangement of guide elements and the base support is particularly advantageous in that a first guide element is fastened to the base support by means of a connection in which at least the first guide element has a first half bore with a first collar, the base carrier has a second half bore, with a second collar, corresponding to the first half bore, the two half bores complement one another to form a complete bore in the joined-together state, a fastening arrangement extends through the complete bore and comprises a first fastening element with a socket which corresponds in form to the collars and which at least partially encloses the collars, and the first guide element is thereby fastened to the base support in a positive manner. This arrangement has particular advantages with respect to the strength of the connection, the number of the structural elements, the required accessibility of the connection for fixing the structural elements and the positional precision, in particular of the guide elements on the base support.

These advantages are further enhanced if the collar is designed to be conical on the outer circumference, with the result that a force which brings together the two half bores is produced when securing the fastening arrangement.

The aforementioned advantages apply particularly in the case of a tachograph having a housing of the aforementioned type.

DETAILED DESCRIPTION OF THE INVENTION

InFIG. 1the housing or the basic housing body1is provided with the reference number2. Two threaded bolts101,102are firmly mounted on a wall2of the bottom of the basic housing body1. The basic housing body1consists of metal.

In the representation shown inFIG. 2, parts of a printer are inserted in the basic housing body1. These parts are a base support3with a printing unit4which is mounted on the base support3and which comprises a printing head, which cannot be seen in the representation. First guide elements19a, barranged on both sides of the base support belong to second guide elements20a,20bwhich are arranged on both sides of a support10and which correspond in form to the first guide elements19a, b. The support10is guided displaceably in the first guide elements19a,19bby means of the second guide elements20a,20balong a circular path in an insertion direction11and counter to the insertion direction11. The surfaces of the guide elements19a,19b,20a,20bwhich bear against one another are designed as sliding bearings.

The base support3has two second half bores84a,84bwhich, together with two first half bores81a,81bon the first guide elements19a,19b, complement one another to form a respective complete bore85a,85b. The first and second half bores81a,81b,84a,84bhave a first collar82a,82bor second collar83a,83bwhich is in each case designed to be conical on its outer circumference.

As represented inFIG. 3, a first fastening element87a,87bdesigned as a conical nut80a,80b, which will be explained further in the text below, can be screwed onto the threaded bolts101,102respectively. The adjoining components, namely the base support3and first guide elements19, are in this way fastened to one another by means of a connection32according to the invention.

FIGS. 4 and 5again show, in an exploded view and as an assembled structure, the components, including further components, arranged in the basic housing body1as shown in the representations ofFIGS. 2 and 3. The printing unit4is mounted resiliently on the base support3by means of an elastic element, namely a torsion spring60, with the result that when the support10is inserted the printing unit4is aligned on centering elements (not depicted in detail) of the support10and is in this way braced so as to compensate for tolerances which are unfavorable to the print quality. A reproducible position of the printing unit4with respect to the support10and to a feed unit5and media unit26mounted on the support10is thus always ensured. This guarantees excellent print quality while at the same time ensuring a comfortable replacement of the printing media.

The representation inFIG. 6shows the first fastening element87or the conical nut80. This substantially comprises a basic body105which is provided with a bore110along a central axis111. The bore110is conically widened in a first section92and the bore110is provided with an internal thread in a second section112. A cylindrical third section113is situated between the first section92and the second section112. The conically widened first section92has a depth of about 70% of the bore diameter. The second section112provided with the internal thread91extends approximately to the same degree. Flats130for applying a tool are arranged on an outer circumference120of the basic body105.