Abstract:
A door check is provided comprising a housing ( 2 ) that can be fixed to a door or door frame and is provided with a first housing half ( 3 ) and a second housing half ( 4 ) which can be connected to each other, and a stay bar ( 24 ) that penetrates an opening ( 23 ) within the housing ( 2 ) and is pivotally mounted on the door frame or door, the housing ( 2 ) and the stay bar ( 24 ) not being fixed to/mounted on the same part. The first housing half ( 3 ) and the second housing half ( 4 ) respectively delimit only one section of the circumference of the opening ( 23 ). In order to create a door check that allows reliable and secure retaining and can be produced at low cost, a braking member ( 13 ) which is biased in the direction of the stay bar ( 24 ) by means of a spring element ( 20 ) is disposed in at least one of the two housing halves ( 3, 4 ).

Description:
FIELD OF THE INVENTION 
     The invention relates to a door arrester. 
     BACKGROUND 
     FR 2 666 616 A1 shows a door arrester for a motor vehicle, which comprises a housing, the housing having a first housing half and a second housing half. The two housing halves define an opening, with the first housing half and the second housing half in each case bounding just one section of the circumference of the opening. The opening is passed through by a retaining rod which is arranged pivotably on a door assembly part, the retaining rod being formed from two metallic, elastic blades which are connected to each other at their outer ends, and which, in a central region, form a cavity for the retaining rod. In each of the two housing halves are formed two cylindrical recesses in which two guide rollers are mounted exclusively rotatably, the guide rollers being arranged in the cavity of the retaining rod, and one of the guide rollers in each case being in contact with a respective flat side of one of the two blades. Two further, exclusively rotatable guide rollers are provided in the housing and are aligned perpendicularly with respect to the guide rollers, and are in contact with thin, outer flat sides of the two blades. The two blades have a wave-shaped profile which is symmetrical with respect to an axis of extent, with the axis simultaneously being the axis of symmetry of the housing. The two guide rollers can be secured in the wave troughs and define preferred latching positions of the arrester. A drawback of this type of door arrester is the fact that the retaining rod comprises two blades forming a cavity, thus resulting in slight deformability of the retaining rod due to frequent use of the door, for example. In the event of deformation of one of the two blades, or else of both of them, the wave profile is deformed asymmetrically and the defined latching positions are displaced or disappear, so that it is no longer certain or even no longer possible that the door will be immobilized. A further drawback is that the guide rollers bring about both the immobilization and the guiding of the retaining rods, with the result that, on the one hand, there has to be a relatively high frictional contact between the guide rollers and the blades for the immobilization and, on the other hand, for the easy movement of the door, a sliding of the guide rollers on the blades has to be realized, thus necessitating a compromise to the disadvantage of the immobilization or to the movement of the door. 
     U.S. Pat. No. 6,446,305 B1 shows a door arrester which comprises a single-part housing which has an opening, the opening being passed through by a retaining rod. The housing is fastened on the door or door frame by means of screws or rivets, and two brake members which in each case comprise a guide and a spring element are arranged in the housing, the spring element prestressing the guide counter to the retaining rod. Each of the two guides has a contact part which is in engagement with the retaining rod and which is formed in such a manner that the contact surface of the contact part forms a line with the retaining rod. The retaining rod is arranged between the two contact surfaces and its wide sides are in engagement with the two contact parts of the brake members. The wide sides of the retaining rod have a rising ramp, with the result that, during the opening of the door, because of the rising of the ramp counter to the two spring elements, the brake members have to overcome a force, and thus the opening movement of the door is inhibited. The ramp of the retaining rod also has a drop, so that the movement of the door is also inhibited during the closing movement thereof. The single-part design of the housing of the door arrester results in a complicated assembly, and the attachment of the door arrester to the door or the door frame is complex, since, after the retaining rod is placed into the housing, the brake members have to be arranged around the retaining rod and at the same time within the housing. 
     U.S. Pat. No. 5,173,991 A shows a door arrester which comprises a housing and a cover covering the housing. The housing and the cover each have an opening which are aligned with respect to each other. The housing and the cover are fastened on the door or the door frame by means of two screws. The two openings are passed through by a retaining rod which has an upper and a lower flat side, with each of the two flat sides having a groove in the direction of extent of the retaining rod. Recesses in which a respective brake member can be secured are provided in the two grooves. Each of the two brake members comprises a ball, which is in contact with the groove of the retaining rod, and a plastic element, which is prestressed in the direction of the retaining rod by a spring element and in which the ball is mounted on the side facing away from the spring element. During an opening or closing movement of the door, the retaining rod is guided by the housing, and the balls of the two brake members are carried along in the groove, with the recesses of the groove constituting latching positions for the movement of the door. A drawback of this type of door arrester is the fact that the assembly of the door arrester is complex, since first of all the two brake members have to be arranged around the retaining rod, and then the retaining rod and the two brake members have to be guided simultaneously into the housing in order subsequently to be able to close the housing with the cover. 
     WO 01 90 518 A1 shows a door arrester, in which a housing of integral design is passed through in an opening by a retaining rod, with two axially displaceable brake members being provided in the housing, which brake members are prestressed in the direction of the retaining rod by a respective compression spring and have spherical engagement domes on a side facing the retaining rod, the engagement domes being in contact with the retaining rod. The retaining rod is arranged between the engagement domes of the two brake members, the retaining rod having latching marks of round design matching the spherical engagement domes. Provided in the housing are two holes for fastening the housing to a motor vehicle by means of screws. The two holes are at the same distance from the retaining rod, the holes being arranged between the plane of displacement of the brake members and a fastening plane of the housing to the motor vehicle. A drawback of this type of door arrester is that the engagement domes of the brake members are of spherical design, so that the latching marks arranged on the retaining rod have to be of relatively large design, with the result that only a limited number of latching positions are possible and also the specific retaining force is limited. A further drawback is that the holes are arranged between the motor vehicle and the plane of displacement of the brake members, thus resulting in a relatively large overall height for the housing and, moreover, the forces exerted on the retaining rod by the brake members exert large moments, in particular on the screws for fastening the housing, because of the distance from the bearing plane of the housing on the corresponding door assembly part. Furthermore, the attachment of the door arrester to the motor vehicle is complex, since first of all the two brake members are placed into the housing, then the retaining rod has to be guided through the opening and, counter to the prestressing force of the two compression springs, through the housing in order finally to be screwed on the motor vehicle. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a door which makes reliable and secure holding possible and can be produced cost-effectively. 
     In accordance with an embodiment of the present invention, a door arrester is provided which includes a housing, a retaining rod, and a brake member. The housing, which can be fastened on one of a door and a door frame, includes a first housing half and a second housing half which are connectable to each other. The retaining rod passes through an opening in the housing and can be pivotably attached on the other of the door and door frame. The first housing half and the second housing half delimit respectively only a portion of the circumference of the opening. The brake member is provided in at least one of the first housing half and the second housing half, and is prestressed by a spring element in the direction of the retaining rod. 
     The effect achieved by designing a housing for a door arrester by means of two housing halves, the two housing halves being connectable to each other, is that the assembly of the housing with a retaining rod passing through an opening of the housing is simplified, in particular by virtue of the fact that each of the two housing halves bounds just one section of the opening, thus facilitating the insertion of the retaining rod. 
     In the case of a door arrester having two housing halves, the arrangement of a brake member prestressed in the direction of the retaining rod by a spring element in at least one of the two housing halves makes it possible for the force acting upon the retaining rod to be transmitted by the brake member to the retaining rod in the axial direction, thus making it possible for the retaining rod to be securely held in the door arrester, and the door is therefore securely held. 
     The holding of the retaining rod by the brake members preferably takes place along a wide side of the retaining rod, as a result of which a contact surface of the brake member with the retaining rod is correspondingly large, and the transmission of force from the brake member to the retaining rod is improved. The brake member is expediently arranged in a manner such that it can be adjusted perpendicularly with respect to an edge of the opening, so that the displacement of the brake member and contact between the brake member and the retaining rod take place in a straight line. As a result, a tilting of the brake member during the adjustment is furthermore avoided, so that the securing force acts directly on the retaining rod. 
     The brake member preferably has an engagement lug which runs transversely with respect to the direction of movement of the retaining rod and is designed as a bead, thus reducing the contact surface of the brake member with the retaining rod. The securing force is thereby simultaneously concentrated onto the smaller contact surface and reinforced, so that the immobilization of the retaining rod is ensured. 
     A respective brake member is preferably provided in each of the two housing halves, with each of the two brake members having an engagement lug. The two brake members are expediently inserted into the two housing halves with the engagement lugs facing each other. As a result, the retaining rod is acted upon by the two brake members on both sides with a retaining force for holding purposes, so that the retaining force acting on the retaining rod is increased. Furthermore, by acting upon the retaining rod on both sides, an undesired tilting in a holding position and/or during the movement is avoided. The spring element preferably comprises a compression spring which has a part which is arranged within the brake member, the brake member having a cavity. As a result, the compression spring is guided securely in the brake member, so that the compression spring can only experience an axial extension during the holding of the retaining rod, and it is not possible for the compression spring to buckle in an undesired direction, with the result that the force acting on the brake member by the compression spring is directed toward the retaining rod. 
     In one preferred refinement, the opening of the housing is of smaller dimensions than both end regions of the retaining rod, so that the two housing halves can be connected by the retaining rod being fitted over. This makes it possible to match the opening of the housing to the size of the retaining rod. The size of the opening also at the same time determines the size of the two housing halves, which means that the two housing halves can also be designed in an advantageously compact manner, so that the door arrester has a compact design. 
     When the door is actuated, the two housing halves are acted upon by the retaining rod with a forced directed transversely with respect to the housing halves. In order to compensate for the transverse force, the two housing halves are preferably connected to each other by rivets, thus expediently stiffening the housing and strengthening the housing against the force. It is therefore possible for the two housing halves to be able to be manufactured from a lightweight material, for example plastic, since the force is compensated for by the rivets. 
     The brake member preferably has a casing surface which has perforations, thus advantageously achieving the effect of the brake member being of resilient design. The resilience of the brake member makes it possible for a tilting of the brake member to be avoided during the insertion into the housing half and for the brake member to be inserted in the desired axial direction. 
     The housing advantageously has two fastening holes which are aligned transversely with respect to a bearing plane of the housing, the fastening holes being arranged on both sides of the two main planes of the housing, which main planes are perpendicular with respect to the bearing plane, thus achieving a secure fastening of the housing. It is furthermore made possible for the two fastening holes to advantageously be arranged next to the brake members, thus advantageously reducing the overall height of the housing. 
     A guide section is provided on the housing, which guide section protrudes over a bearing plane of the housing with the door assembly part—the door or door pillar—and can be secured in a form-fitting manner to the corresponding door assembly part. This makes it possible for the door arrester to be easily attached to the door assembly part, since an unambiguous alignment of the door arrester with respect to the door assembly part is predetermined by the protrusion of the guide section. It is furthermore avoided as a result that the door assembly part and the door arrester are at a distance from each other, the door arrester thus being arranged in a space-saving manner on the door assembly part and not being negatively conspicuous visually to a user of the door or the retaining rod being perceived as annoying. 
     The guide section preferably has ribs which expediently bound the edge of the opening of the housing, and which have a progressively designed groove. The effect achieved by this is that, when the housing of the door arrester is attached, the orientation of the housing with respect to the door assembly part is predetermined by means of the groove. This ensures that the housing is attached in the desired manner. 
     The effect achieved by the expedient arrangement in each case of a rib on one of the two housing halves is that the fastening forces between the housing and the door assembly part are distributed uniformly to the two housing halves, therefore a secure attachment of the door arrester is ensured. Furthermore, a tilting or an oblique attachment is avoided. 
     In order to ensure a secure attachment of the door arrester, a hole for screws is preferably provided on each of the two housing halves and are provided for fastening the door arrester. The fastening provided by means of screws may be regarded as an alternative possibility of fastening the door arrester, or else as an additional fastening assisting the fastening by means of the guide sections. In the case of an additional fastening, the housing is first of all attached to the door assembly part by means of the guide sections in order then to be supplementarily fastened by means of the screws. 
     An intersecting plane which is aligned perpendicularly with respect to the direction of extent of the retaining rod is preferably provided in each case on the two housing halves. The two housing halves are advantageously connected to each other at the intersecting planes. The intersecting planes define an unambiguous connecting plane for the two housing halves, as a result of which erroneous assembly of the two housing halves is avoided. The assembly is advantageously facilitated by aligning and guide elements on the intersecting planes, with one aligning element expediently being assigned to one guide element. 
     In order to make the manufacturing and the production of the door arrester more effective, the two housing halves are advantageously of identical design. A single production line is therefore required and a large series length achieved. 
     The two housing halves are preferably produced from plastic as injection-molded parts, with a metallic thread for the screws advantageously being injected at the same time into the holes, as a result of which a complex subsequent fitting of the screw is omitted. 
     By means of a method for producing a door arrester having a housing designed in two parts, in which a first housing half and a second housing half bound just one section of an opening passed through by a retaining rod and a brake member is provided in at least one of the two housing halves, a simple and secure assembly is achieved by the fact that the two housing halves are connected only after the insertion of the retaining rod while prestressing means for the brake member are prestressed by the retaining rod. The effect achieved by this is that the insertion of the retaining rod and the prestressing of the brake members take place in a single working step. The effect furthermore achieved is that the door arrester can be preassembled in a single part and is then fastened on the designated door assembly part. 
     In one advantageous development of the method, the brake member is prestressed in one of the two housing halves in the direction of the retaining rod by a spring element which forms the prestressing means. Both the spring element and the brake member are inserted into the particular housing half before the connection of the two housing halves. The effect achieved by this is that, when the door arrester is assembled, an additional retention of the brake member during the insertion of the retaining rod is avoided, since both the brake member and the spring element are retained solely by the housing half. In addition, this predetermines the alignment of the brake member with the retaining rod in the desired manner and a possible tilting of the brake member and/or of the spring element caused by the insertion of the retaining rod is advantageously avoided. 
     A method for attaching a door arrester, in which a first housing half and a second housing half are connected to either the door or door frame only after the retaining rod is inserted, and in which the intersecting planes are aligned during the connection perpendicularly with respect to either the door or door frame, permits a simple installation by virtue of attachment to either the door frame or the door taking place after the retaining rod is inserted, with the intersecting planes of the two housing halves advantageously being aligned perpendicularly with respect to the door or the door frame. The perpendicular arrangement of the intersecting planes defines an unambiguous position of the housing during the attachment with respect to the motor vehicle, as a result of which the alignment can be checked at any time and it is ensured that the housing is fastened in the desired position. 
     In one preferred development of the method, the housing is connected to either the door or door frame by means of a rotational movement, with a bayonet connection preferably being provided. This avoids a complex fastening operation, since the bayonet connection enables the two parts to be connected by means of a single rotation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in more detail below using preferred exemplary embodiments of a door arrester according to the invention with reference to the attached drawing. 
         FIG. 1  shows a cross section through a preferred exemplary embodiment of a door arrester according to the invention. 
         FIG. 2  shows a plan view of a housing half of the housing of the door arrester from  FIG. 1 . 
         FIG. 3  shows a front view of the housing half from  FIG. 2 . 
         FIG. 4  shows an exploded illustration of the door arrester from  FIG. 1 . 
         FIG. 5  shows an enlargement of a detail of the housing of the door arrester from  FIG. 2 . 
         FIG. 6  shows a second exemplary embodiment of a door arrester according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 4  show a first exemplary embodiment of a door arrester  1 , in which a housing  2  which can be fastened on one of the door assembly parts—the door or door frame—has an opening  23  with a rectangular cross section which is passed through by a retaining rod  24  arranged on the other of the door assembly parts. Brake members  14  which are accommodated in the housing  2  and are prestressed axially in the direction of the rectangular opening  23  act upon the retaining rod  24 , in which case, owing to latching recesses  25  formed in at least one of the two flat sides of the retaining rod  24 , the brake members penetrate into a latching recess  25  or are pressed back therefrom, depending on the position of the retaining rod  24 . The housing  2  is placed against the door assembly part along a bearing plane  3   a.    
     The housing  2  comprises a first housing half  3  and a second housing half  4  which have an identical design, so the construction of the first housing half  3  will first of all be described by way of example for both housing halves  3 ,  4 , with the second housing half  4  being of corresponding design and being provided with reference numbers. 
     The housing half  3  is designed as a hollow cylinder which is open at one end, comprising a closed base side  5  facing away from the opening  23 , a casing  6  and a front side  7  which comprises a circular release opening  13  of the hollow cylinder, the circular release opening  13  merging into the polygonal opening  23  transversely with respect thereto. 
     The front side  7  comprises a first edge  7   a , a second edge  7   b , a third edge  7   c  and a fourth edge  7   d  which bound the circular release opening  13  of the housing half  3 . The first and the second edges  7   a ,  7   b  and the third and the fourth edges  7   c ,  7   d  are arranged opposite each other in pairs. The first and the second edges  7   a ,  7   b  protrude by a distance a in relation to the third and the fourth edges  7   c ,  7   d . A rectangular gap  10  is produced which is arranged in a central region of the front side  7  and is aligned symmetrically with respect to an axis S symmetrically dividing the front side  7  (cf.  FIG. 2 ). The third and the fourth edges  7   c ,  7   d  are aligned with the circular release opening  13  of the housing half  3  whereas, by contrast, the first and the second edges  7   a ,  7   b  protrude by the distance a. 
     An aligning element  11  which is designed as a projection is arranged in the second edge  7   b . A guide element  12  designed as a recess is provided in the first edge  7   a  (cf.  FIG. 3 ). When the two housing halves  3 ,  4  are assembled, the aligning element  11  or guide element  12  of the first housing half  3  is brought into engagement with the guide element  12  or aligning element  11  of the second housing half  4 , so that the two housing halves  3 ,  4  can be oriented in the desired alignment with respect to each other and can be axially plugged together. 
     Furthermore, in the two edges  7   a ,  7   b  in an upper half, a respective hole  29  passing through these edges parallel to the hollow cylinder is provided. In order to connect the two housing halves  3 ,  4 , a rivet  30  is introduced into the holes  29  and secured. 
     On the side facing away from the bearing plane  3   a , a damping strip  26  of soft plastic which is arranged above the outer surface formed by the casing  6  is fitted transversely with respect to the holes  29  along two opposite circumferential regions of the opening  23 . 
     A projection  8  which is and has a semicircular profile (cf.  FIG. 2 ) is arranged approximately over half of the height of the casing  6  integrally with the casing  6 , approximately in the center of its extent and adjacent on one side to and laterally offset from the axis S. 
     In the projection  8 , a hole  9  is formed perpendicularly with respect to the bearing plane  3   a , the lateral arrangement of the projection  8  meaning that the hole  9  does not penetrate into the cavity of the housing half  3  or support it from below. The hole  9  ends flush with a flat side  3   a  of the housing half  3 , which side forms a bearing plane for the housing  2  with the door or the door frame. 
     A metallic threaded component  9   a  is arranged within the hole  9  and is provided for the fastening of the housing half  3  by means of screws. The projection  8  extends approximately over that half of the overall height of the housing half  3  which faces the flat side  3   a , with the hole  29  for the rivets  30  being arranged in the other half. 
       FIG. 1  shows a cross section of the door arrester  1 , the housing half  3  having a U-shaped cross section. In this case, the base side  5  forms the base of the U and the two limbs  6   a ,  6   b  of the U are formed from cuts in the casing  6 . 
     A brake member  14  is inserted through the circular release opening  13  into the hollow cylinder formed in the housing half  3 , the brake member being guided axially in said hollow cylinder and having a shorter extent than the depth of the hollow cylinder, so that an axial displacement of the brake member  14  within the housing half  3  is possible. 
     The brake member  14 , which is produced as a hollow part from plastic by injection molding, comprises a front end side  15 , a casing surface  16  and a rear side  17  which faces away from the front end side and has a central access  17   a  bounded by the casing surface. In the interior of the brake member  14 , the casing surface  16  bounds an inner space of hollow-cylindrical design. 
     The front end side  15  is designed with an engagement lug  18  which extends transversely with respect to the casing surface  16  over the diameter of the brake member  14  and is of rounded design in cross section ( FIG. 5 ) and is of long stretched-out design along its extent in longitudinal section. The engagement lug  18  is formed essentially complementarily to latching recesses  25  which are aligned in the retaining rod  24 , essentially transversely with respect to its direction of movement through the opening  23  defined in the housing  2 . 
     The engagement lug  18  is dimensioned in such a manner that the first and second edges  7   a ,  7   b , which protrude out of the front side  7  of the housing half  3  by a distance a, protrude further by a distance c, which is smaller in terms of amount than the distance a, than a frontmost edge of the engagement lug  18  of the brake member  14 . 
     The surface region of the front end side  15  which faces the inner space has a central ring  22  which is aligned coaxially with the brake member  14 , and an inner radial support for a spring element  20  which is designed as a helical spring which is supported on that surface region of the front end side  15  which faces the inner space, with a first end  20   a  against the base side  5  of the housing half  3  and with a second end  20   b  axially against the annular section bounded by the ring  22  and casing surface  16 , and is radially surrounded at least in its proximal region by the casing surface  16 . The force exerted on the brake member  14  by the spring element  20  presses the end side  15  of said brake member forward in the direction of the retaining rod  24 , with the spring element  20  being pushed back and stressed in accordance with the position of the latching recesses  25  by the actuation of the vehicle door. On the inner end side of the base  5 , a ring  21  is likewise arranged coaxially with the ring  22 , which ring centers the helical spring  20  and guides it radially from the inside and also axially over the extent of the ring  21 . 
     The casing surface  16  has three perforations which extend axially along the brake member  14  starting from the rear side and are designed as cutouts  27  (cf.  FIG. 4 ), the cutouts  27  being arranged along the circumference of the casing surface  16  in such a manner that in each case two adjacent cutouts  27  are offset with respect to each other by an angle of 120°. 
     The cutouts  27  extend approximately over half of the length of the brake member  14 . In the open rear side  17  of the brake member  14 , regions  27   a  which remain of the cutouts  27  are cut free. In a region facing the end side  15  of the brake member  14 , the cutouts  27  have a rounded region, the cutout  27  widening in profile from the rounded region to the rear side  17 . The cutouts  27  enable the brake member  14  to be expediently of resilient or flexible design, with the result that, if the brake member  14  tilts, the force acting on the brake member  14  from the retaining rod  24  because of the movement of the door can deform said brake member a little and it can then move back into an actuable position. 
     The casing surface  16  has, on the outside, an axially extending, outer guide fluting  16  of respectively rounded grooves and ribs which are provided in an alternating manner, which guide fluting engages with an inner guide fluting of complementary design in the hollow cylinder of the housing half  3  and in such a manner defines a linear guide for the brake member  14 , with the materials of the corresponding parts being optimized in respect of the sliding contact. 
     Furthermore, along the axial extent of the casing surface  16  of the brake member  14 , two ribs which are raised in relation to the guide fluting are provided offset opposite each other by 180°, which ribs interact with corresponding, depressed grooves  28   a  formed axially in the casing  6  of the housing half  3 ,  4  (cf.  FIG. 5 ) and therefore define a means of securing against rotation  28  in order to ensure a positionally correct installation of the brake members  14  in the corresponding housing part  3 ,  4 . 
     The length of the brake member  14  is shorter than the depth of the hollow cylinder, so that the rear side  17  is always at a distance b from the base side  5  of the housing half  3 , by which distance the brake member  14  can be displaced within the housing half  3 , compressing the spring element  20 . 
     When the spring element  20  is relaxed, a proximal region of the casing surface  16 , in relation to which the engagement lug  18  protrudes, is aligned approximately with the circular release opening  13  of the hollow cylinder. 
     The door arrester  1  comprises two identical housing halves  3 ,  4  which are connected to each other with the respective front side  7  facing each other, the first and second protruding edges  7   a ,  7   b  of the two housing halves  3 ,  4  being in contact with each other in a flush manner and defining an intersecting plane  2   a  for each of the two housing halves  3 ,  4 . The two intersecting planes  2   a  define a connecting plane V for the housing  2  (cf.  FIG. 2 ), the two housing halves  3 ,  4  being connected to each other symmetrically with respect to the connecting plane V; in particular, the two housing halves  3 ,  4  each have a brake member  14 . 
     The respectively defined gap  10  of the two housing halves  3 ,  4  is supplementary to the opening  23  for the retaining rod  24 . The opening  23  has a rectangular shape and is bounded by the individual edges  7   a ,  7   b ,  7   c  and  7   d  supplementary to a boundary for the opening  23 , the edges  7   a ,  7   b ,  7   c ,  7   d  of the individual housing halves  3 ,  4 —as seen as a constructional unit—in each case bounding just one section, in the present half, of the opening  23  of the housing  2 . 
     The opening  23  of the housing  2  is passed through by a central region of a retaining rod  24 . The retaining rod  24  has a rectangular outer profile and is formed as a solid part, for example of hard rubber with a metal core or the like. The retaining rod  24  has essentially a width which is greater than twice the distance c of the brake member  14  from the first and second edges  7   a ,  7   b , with an intermediate region with respect to the axially opposite brake members  14  being defined by the distances c. The dimensions of the opening  23  are matched to the dimensions of the central region of the retaining rod  24  and are smaller than end regions  24   a ,  24   b  which are provided for the pivotable fastening of the retaining rod  24  on the particular door assembly part and as an initial and final deflection for the door opening, an end region  24   b  being arranged pivotably on the retaining rod  24  by means of a bolt  24   c.    
     Two latching recesses  25  are provided in the outer circumference of the retaining rod  24 , which recesses are designed as curvatures in the retaining rod  24 , one latching recess  25  being arranged in each case on one side of the retaining rod  24 . The shape of the curvatures is matched to the profile of the bead of the engagement lugs  18  arranged on the brake members  14 . The brake members  14  are prestressed in the direction of the retaining rod  24  by the compression springs  20  and are in frictional contact with the latching recesses  25  of the retaining rod  24 . The latching recesses  25  define a preferred securing position for the door. It has to be understood that a plurality of latching recesses  25  which define a plurality of preferred immobilization positions for the door can be arranged on the retaining rod  24 . 
     When the door is opened, the retaining rod  24  is displaced through the opening  23  of the housing  2 , the brake members  14  which are prestressed by the compression springs  20  being displaced into a rear region of the particular housing half  3 ,  4  and the frictional contact of the brake members  14  with the retaining rod  24  becoming a sliding contact, so that the retaining rod  24  can be guided without great effort through the opening of the housing  2 . If the movement of the door is stopped, the sliding contact again becomes a frictional contact and the brake members  14  latch in one of the latching recesses  25  of the retaining rod  24 , the two brake members  14  acting upon the retaining rod  24  on both sides at the latching recesses  25  with the force imparted by the compression spring  20  and fixing it and therefore securely held the door. 
     During the assembly of the door arrester  1 , first of all the two brake members  14  are inserted into the two housing halves  3 ,  4  with compression springs  20  inserted into the cavity. The retaining rod  24  is then brought between the two housing halves  3 ,  4  in such a manner that the central region of the retaining rod  24  is engaged around by the opening  23  of the housing  2 . During the connection of the two housing halves  3 ,  4  by means of the rivets  30 , the aligning elements  11  are brought into engagement in a matching manner with the guide elements  12  in order to obtain the desired alignment of the two housing halves  3 ,  4  with respect to each other. 
     The two housing halves  3 ,  4  are connected to each other by the two rivets  30  at the protruding edges  7   a ,  7   b  along the connecting plane V defined by the intersecting planes  2   a . The brake members  14  come into contact with the retaining rod  24 , since the distance between the two brake members  14  corresponds to twice the distance c and the width of the retaining rod  24  is greater. As a result, the brake members  14  are displaced at the same time in the housing halves  3 ,  4  counter to the direction in which the force of the compression springs  20  acts, with the brake members  14  therefore prestressed in the direction of the retaining rod  24  by the compression springs  20 . The door arrester  1  can then be attached to the motor vehicle by means of screws in the holes  9 . 
       FIG. 6  shows a second exemplary embodiment of a door arrester  1 ′. The same reference numbers as in the first exemplary embodiment refer to the same or structurally comparable parts. Since the manner of operation of both exemplary embodiments of the invention is comparable, it is essentially the differences between the two exemplary embodiments which will be discussed below. 
     In contrast to the exemplary embodiment shown in  Figs. 1 to 4 , the housing halves  3 ′,  4 ′ which are shown in  FIG. 6  and form a housing  2 ′ do not have holes  9  for the fastening of the housing  2 ′. On the contrary, two guide sections  40  are provided which are aligned perpendicularly with respect to the edges  7   a  of the two housing halves  3 ′,  4 ′. The guide sections  40  are aligned with the particular front side  7  of the housing halves  3 ′,  4 ′. The guide section  40  is offset laterally with respect to the axis of symmetry S of the first housing half  3 ′ in the direction of the edge  7   b.    
     The guide section  40  has a rib  40   a  and a groove  41 . The groove  41  runs parallel to the front side  7  of the housing half  3 ′ at a distance, the distance increasing in profile from the edge  7   a  in the direction of the edge  7   b . The groove  41  is of progressive design. 
     In contrast to the first exemplary embodiment, the door arrester  1 ′ is now attached to the motor vehicle as follows. In the region provided for the fastening of the door arrester  1 ′ the motor vehicle has an aperture, the dimensions of the aperture corresponding to the dimensions of the opening  23  of the housing  2 ′. The door arrester  1 ′ is guided on the aperture, with the grooves  41  at the smallest distance from the front side  7  bearing against the aperture. The grooves  41  can be inserted into the aperture of the motor vehicle. The door arrester  1 ′ is then rotated in the clockwise direction and the grooves  41  which are of progressive design and the edge of the aperture of the motor vehicle form a nonpositive connection, with the ribs  40   a  being guided within the opening. 
     As an alternative, it would also be possible to arrange the progressivity of the groove  41  in the reverse direction, the distance decreasing in profile from the edge  7   a  in the direction of the edge  7   b . In order to fasten the door arrester  1 ′, after it has been inserted into the aperture of the motor vehicle, a rotation counterclockwise is then required. 
     It has to be understood that both exemplary embodiments described above can be combined in such a manner that the door arrester is first of all connected to the motor vehicle by means of the rotational movement and is then further securely fastened by means of the screws which are arranged in holes provided on the housing halves.