DE8517499U1 - Device for fixing a sash frame that can be rotated about a rotation axis to a window frame - Google Patents

Description

Patent attorneys Dipl.-Ing. H. WEtCKüi..\ ^> tfN _h ^l Di'ki,:- ^: Bitrs. Dr. K. Fincke

Dipping. F. A.Weickmann, Dipl.-Chem. B. Hubf.r Dr.-Ing. H. Liska, Dipl.-Phys. Dr. J. Prechtel

SOOOMONCHEN 86

PO BOX 860 820

MDHISTRASSE 22

TELEPHONE (3 89) «C3 52

TEUX 5:2 621

TELIGRAM PATINTWFICKMANN MUNICH

CIP

Aug. Winkhaus
GmbH & Co. KG
August-Winkhaus-Strasse

4404 Telgte

Device for fixing a sash frame that can be rotated about a rotation axis to a window frame

The invention relates to a device for fixing a sash frame that can be rotated about a rotation axis on a frame in a predetermined rotation opening position on a door, a window or the like, comprising

a display bracket which is hinged at one end to one of two matching frame legs of the sash frame and the frame by a swivel joint and is connected at its other end to the second of these matching frame legs by a swivel-sliding joint,

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Locking means/ which automatically immobilize the setting of the opening tab in relation to the frame hinges when the sash frame moves from the closed position into the predetermined rotary opening position,

and hand-operated release devices for these locking devices.

Such a device is known from the German utility model 84 17 729-

With the known arrangement, the sash frame can only be opened up to the predetermined opening position. Any further opening of the sash frame is not easily possible for a layperson, i.e. for the resident of the apartment equipped with the window.

The invention is based on the object of creating a device of the type described above, in which the sash frame can also be opened into a further rotary opening position, in particular into a fully open position, by means of simple adjustment measures.

To solve this problem, the invention proposes,

that the swivel joint is arranged on a sliding piece that is movable in the longitudinal direction of the first frame leg in a sliding piece guide,

that this sliding piece is preloaded by spring means towards a basic position,

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that the gasification means are formed by a release and locking cam arranged on the deployment tab on the one hand and a cam engagement edge on the slide guide which interacts with this release and locking cam on the other hand, whereby when the deployment tab pivots around the pivot joint as the casement approaches the predetermined rotary opening position, the interaction of the release and locking cam and the cam engagement edge initially causes the slide to disengage from the basic position against the action of the spring means and only when the predetermined rotary opening position is reached do the release and locking cam and the cam engagement edge engage in mutual locking under the action of the slider returning to the basic position forced by the spring means, \

that the locking mechanism can be released by manually moving the slider from the basic position against the action of the spring means and

that the pivoting sliding joint can be disengaged in the closed position of the sash frame by disengaging the sliding piece from its basic position against

the action of the spring means causes the opening tab to be displaced relative to the second frame leg.

The device according to the invention can be attached to a wide variety of types of windows, in particular simple | turn windows with a vertical axis of rotation, tilt windows with a horizontal axis of rotation (tilt axis), turn-tilt windows with a horizontal axis of rotation (tilt axis) and a vertical axis of rotation and pivot windows with a horizontal axis of rotation (swing axis). In all cases, the device can be arranged so that the axes of the pivot

joint and the pivoting-sliding joint are parallel to the respective axis of rotation, but also so that the axes of the pivoting joint and the pivoting-sliding joint are essentially perpendicular to the axis of rotation of the sash frame.

The release and locking cam can be designed with a release curve and adjacent to the release curve of a latch, whereby the release curve, when the sash frame is transferred to the predetermined rotary opening position, in cooperation with the cam engagement edge, causes the slider to be released from the basic position against the action of the spring means and the latch, when the predetermined rotary opening position is reached, takes up the cam engagement edge and thus immobilizes the release tab.

[ A simple design for the swivel-sliding device

; steering consists of a fork-like open sliding slot

&iacgr; a fitting attached to the second frame leg

\ partly on the one hand and a slotted engagement bolt on the

other, i.e. the end of the extension bracket that is freely movable relative to the first frame leg. The slotted engagement bolt can be pulled out of the open fork end

escape if the sliding piece counteracts the action of the i;
\ Spring means by manual action from the basic position

is deployed.

A design for the display flap that is simple in its construction and acceptable in terms of space requirements consists in two parallel slats forming the display flap, with these slats accommodating the sliding piece between them at one end of the display flap

and are connected at the other end by the slot engagement ^bolt . A rib of the fitting part attached to the second frame leg, which has the sliding slot, can engage between the two slats.

The sliding piece can be designed as a manually operated release button at its end remote from the opening tab. This release button is available once to

\ the locked predetermined opening position of the sash

frame to release the locking mechanism again, but also to enable the sash frame to be fully opened when it is in the closed position, ie to open it beyond the predetermined opening position. This is a particular simplification in that one and the same manual operating device is available for two different functions.

In order to achieve a stable and aesthetically pleasing design, it is proposed that the sliding piece guide comprises an elongated housing with a rectangular cross-section, which accommodates the opening tab along its entire length when the sash frame is in the closed position and has an opening in one of the long side walls for the opening tab to pass through. The elongated housing then only serves as a sliding piece guide over part of its length and over the rest of its length to conceal and, if necessary, support the opening tab. An end edge of the opening close to the sliding piece can be designed as a cam engagement edge.

In order to lock the sash frame in the predetermined opening position and/or in the closing position and to secure it against unintentional opening from the inside and/or outside,

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it is proposed that the sliding piece can be locked in its basic position relative to the sliding piece guide, j

The opening tab in the basic position of the slider can be either parallel to the corresponding
first frame leg according to the closed position
of the sash frame and through the interaction of the
Release curve with the cam engagement edge in this
Parallel position is fixed or the display pocket |

in the predetermined opening position of the sash |

frame is immobilized by the interaction of the latch with the cam | engaging edge. Such a locking mechanism I serves, for example, to protect against accidental I opening of the casement frame by children. i

The locking can be done, for example, by a grub screw in the
sliding piece, in particular one with
Allen key, which engages with a corresponding ;

opening in the slide guide can be screwed isu. &xgr;

With regard to the right and left usability of the device , it is proposed that it be used in relation to a
to the axes of the swivel and swivel-sliding joint
vertical plane of symmetry is symmetrical.

With regard to easy release access in the predetermined rotary opening position, it is advantageous if the
The sliding guide can be attached to a sash frame leg. However, it is quite possible to
can also be attached to a frame leg.

The device according to the invention is, since it is independent

of other parts of a fitting system/ in particular

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also suitable for retrofitting, i.e. for subsequent installation on a window or door.

In order to eliminate difficulties in fastening the sliding guide in the area of the sliding piece, it is proposed that a hollow rivet be provided that passes through the sliding piece guide and the sliding piece to guide the sliding piece and/or to restrict the movement of the sliding piece and/or to support the spring means, which rivet receives a fastening screw for fastening the sliding piece guide to the respective frame leg. In this way, at least two functions are fulfilled by one and the same part, namely the hollow rivet.

If the device is installed in such a way that the axes of the swivel joint and the swivel-sliding joint are parallel to the respective axis of rotation, the opening width can be varied by changing the location of the device along the frame legs without any other changes to the device.

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According to another point of view, the invention is based on the state of the art according to DE-GM 84 17 729, on a device for securing a sash frame that can be rotated about a rotation axis on a frame in a rotary opening position, comprising

a display bracket which is hinged at one end to a first of two matching frame legs of the sash frame and the frame by a pivot joint and is connected at its other end to the second of these matching frame legs by a pivot-sliding joint,

and locking means which maintain the setting of the opening tab relative to the frame legs in a rotary opening position in the absence of external force,

The extension arm can be uncoupled from one of the frame legs.

In order to enable the sash frame to be opened to a wider open position, it is suggested that

that the swivel joint is arranged on a sliding piece that is movable in the longitudinal direction of a first frame leg in a sliding piece guide,

that this sliding piece is preloaded by spring means towards a basic position,

that the swivel-sliding joint is formed by a sliding slot that is open at one end like a fork in a fitting part attached to the second frame leg and an engagement bolt at the other end of the projection,

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that in the closed position of the sash frame to the frame, the slot engagement bolt lies within the sliding slot with the sliding piece in the basic position

and that the slot engagement bolt can be disengaged from the sliding slot in the closed position of the sash frame to the frame by moving the sliding piece against the action of the spring means from the basic position into a decoupling position.

C. In order to enable the slotted engagement bolt to be re-engaged in the sliding slot without having to act on the sliding piece again, it is further proposed that a bevelled edge be attached to the fitting part adjacent to the open end of the sliding slot, which edge is located in the area of the slotted engagement bolt when the sliding piece is in the basic position.

The accompanying figures illustrate the invention using an embodiment . They show:

Fig. 1 shows schematically a rotating window with a device according to the invention?

Fig. 2 is a view of the display device in the direction of arrow II of Fig. 1, partially sectioned according to line IV-IV of Fig. 5;

Fig. 3 is a view corresponding to that of Fig. 2

with the sash frame in the closed position;

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Fig. 4 a view corresponding to that of Fig* with the sliding piece pressed downwards in preparation for a full opening of the sash frame and

Fig. 5 is a section along line V-V of Fig. 4.

In Fig. 1, one can see a casement frame, which is generally designated with 10, and a frame, which is generally designated with 12. The two frame legs of the casement frame and the frame, which are remote from the axis of rotation, are designated with 10a and 12a respectively. Between the frame legs 10a and 12a, a device 14 is provided for fixing the casement frame 10 relative to the frame 12, which allows a predetermined opening angle Δ5C to be set around the axis of rotation A-A.

According to Fig. 2, further details of Fig. 1 can be seen. A fitting plate 16 on the frame side is attached to the visible surface 12b of the sash frame leg 12a, which plate carries a rib with a fork-like open sliding slot 18.

A housing 20 of approximately square cross-section is attached to the casement, specifically to the overlapping surface 10b of the casement leg 10a. This housing 20 has an opening 22 in its side wall 24 facing the frame leg 12a.

A sliding piece 26 is arranged in the housing 20 so that it can move. In Fig. 2, the sliding piece 26 is in its uppermost position and can be pushed downwards from the basic position against the action of a helical compression spring. A deployment tab 30 is articulated on the sliding piece 26 by means of a swivel joint 32. The

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The extension tab 30 consists, as can be seen in Fig. 5, of two slats 30a and 30b, which are mounted on the sliding piece 26 on either side of a downwardly directed extension tongue 26b of the sliding piece 26 by stub shafts 32a, 32b. The stub shafts 32a and 32b together form the swivel joint 32. At their other end, the two slats 30a, 30b of the extension tab 30 are connected to one another by a slotted engagement bolt 34 which engages in the fork-like open slot 18, whereby the two slats 30a and 30b are located on either side of the rib 16 in Fig. 2. In Fig. 2, the sash frame 10 is fixed relative to the frame 12 in that, on the one hand, the slotted engagement bolt 34 engages in the fork-like slot 18 and, on the other hand, the projection tab 30 is immobilized relative to the housing 20. A cam 36 is attached to the slat 30b (the same applies to the slat 30a), which has a release curve 36a and a latch 36b. In Fig. 2, a cam engagement edge 38, which limits the upper end of the opening 22 in the side wall 24, is in engagement with the latch 36b. As long as the sliding piece 26 assumes the basic position set in Fig. 2 under the action of the screw compression spring 28, the projection tab 30 cannot be pivoted relative to the housing 20. This is the reason for the immobilization of the sash frame 10 relative to the frame 1 2.

If you want to move the sash frame from the predetermined opening position 0>C according to Fig. 1 and 2 into the closed position, you only need to press on the sliding piece 26, the upper end 26a of which is designed as a push button, until the cam 36 with its release curve 36a is below the cam engagement edge 38

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is creten so that the outer tab 30 can now be pivoted in the counterclockwise direction as shown in Fig. 2. When the sash frame 10 is then brought closer to the frame 12, the pivot tab 30 rotates in the counterclockwise direction around the pivot joint 32. After just a small rotation of this kind, the pressure on the push button 26a can stop because the release curve 36a has then come into engagement with the cam engagement edge 38. As the sash frame 10 approaches the frame 12, the release curve 36a slides on the cam engagement edge 38, reaching the position shown in Fig. 3. In this position as shown in Fig. 3, the sliding piece 26 has returned to the basic position thanks to the shape of the release curve 36a (see Fig. 3). In Fig. 3 it can be seen that in the closed position of the casement frame the slot engagement bolt 34 still engages in the fork-like open sliding slot 18, so that when the casement frame is opened again relative to the frame in the direction of the predetermined rotary opening position shown in Fig. 1 and 2, the readiness for locking in the predetermined rotary opening position still exists. When the casement frame again moves into the predetermined rotary opening position according to Fig. 1 and 2, the release curve 36a rolls on the cam engagement edge 38, whereby compared to the basic position according to Fig. 3 the sliding piece 26 is initially pulled downwards against the action of the helical compression spring until finally the cam engagement edge 38 can fall into the latch 36b of the cam 36 and thus the sliding piece 26 rolls back into the basic position, whereby the setting according to Fig. is achieved again.

If it is intended to open the window using the method shown in Fig. 1,

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If the window is to be opened beyond the predetermined rotational opening position «^, this is possible by pressing the sliding piece 26 downwards from the position shown in Fig. 3 to the position shown in Fig. 4 before the rotational opening of the sash frame in the closed position begins. If the rotational opening of the sash frame now begins, the slotted engagement bolt 34 can emerge laterally from the sliding slot 18 so that the sliding joint 34, 18 is uncoupled.

In Fig. 4, a through hole 40 of the housing can be seen at the lower end of the housing 20 and in Fig. 5, a hollow rivet 42 penetrating the housing 20 can be seen at the upper end of the housing. The through hole 40 and the hollow rivet 42 are intended to accommodate fastening screws with which the housing 20 is fastened to the overlapping peripheral surface 10b. The hollow rivet 42 penetrates an elongated hole 44 of the sliding piece 26. A hole 46 is made in the upper end of the sliding piece 26 and is closed by a plug 48. The helical compression spring 28 is housed between the plug 48 and the bore 46, one end of which is supported against a shoulder surface of the plug 48 and the other end against the hollow rivet 42. In this way, the helical compression spring 28 tries to push the sliding piece 26 upwards into the position shown in Fig. 2 and 3. In Fig. 4 and 5, on the other hand, the sliding piece 26 is pressed downwards against the effect of the helical compression spring 28.

In the basic position of the slider 26 shown in Fig. 2 and 3, a grub screw 50 with an Allen head accommodated within the slider 26 is in alignment with a hole 52 in the housing 20. The grub screw

screw can be unscrewed with an Allen key until its outer end engages in the hole 52. Then it is no longer possible to move the sliding piece 26 from the basic position. This means that both the state according to Fig. 2 (casement frame in predetermined opening position c*^) and the state according to Fig. 3 (casement frame in closed position) can be locked at will.

From Fig. 2 and 3 it can be seen that a bevel 16b is attached to the lower end of the rib 16a of the fitting part 16. When the sliding piece 26 assumes its uppermost position according to Fig. 3, the slot engagement bolt 34 is at the height of the bevel 16b. This means that by pressing the sash frame 10 against the frame 12, the slot engagement bolt 34 can be brought into engagement with the bevel 16b. This also means that the slot engagement bolt 34 exerts a pull on the extension tab 30 and on the sliding piece 26, so that the sliding piece 26 is pulled downwards with the extension tab 30 and the slot engagement bolt 34 engages in the sliding slot 18. After locking, the slide piece 26, the extension tab 30 and the slotted engagement bolt 34 return to the position shown in Fig. 3.

Claims (1)

Patent attorneys Dipl.-Ing. H/^EJcfiMAiti &ngr;; DiPiI-iPilYS. Dr. K. Fincke »-&bull;&bgr; tr» ·· ■ ■ t * ^p O Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber Dr.-Ing. H. Liska, Dipl.-Phys. Dr. J. Prechtel 8OCO MUNICH 86 PO BOX 860 820 MDHLSTRASSE 32 TELEPHONE (0891 98 OJ 52 TELEX 522 621 TELEGRAM PATENTWEICKMANN MÖNCHEN CIP H! 1988 Aug. Winkhaus
GmbH & Co. KG
August-Winkhaus-Strasse Telgte Device for fixing a sash frame that can be rotated about a rotation axis to a window frame Protection claims 1. Device for fixing a sash frame (10) that can be rotated about a rotation axis (A-A) to a frame (12) in a predetermined rotation opening position oC, comprising a display tab (30) which is hinged at one end to a first (10a) of two associated frame legs (10a, 12a) of the sash frame (10) and the frame (12) by a pivot joint (32) and is connected at its other end to the second (12a) of these associated frame legs (10a, 12a) by a pivot-sliding joint (18, 34), Locking means (36, 38) which allow the adjustment of the extension bracket (30) relative to the frame legs (10a, 12a) automatically immobilize when the sash frame (10) comes from the closed position into the predetermined rotary opening position, and manually operable release means (26a) for these locking means (36b, 33), characterized, that the swivel joint (3 2) is attached to a longitudinal V of the first frame leg (1Oa) in a sliding piece guide (20) movable slide (26), that this sliding piece (26) is preloaded by spring means (28) towards a basic position, that the locking means (36b, 38) are formed by a release and locking cam (36) arranged on the deployment tab (30) on the one hand and a cam engagement edge (38) on the sliding piece guide (20) cooperating with this release and locking cam on the other hand, wherein when the cam is approached of the sash frame (10) to the predetermined rotary opening position &ogr;», caused pivoting movement of the deployment tab (30) about the pivot joint (32) by the interaction of the disengagement and locking cam (36) and the cam engagement edge (38) initially causes a disengagement of the sliding piece (26) from the basic position against the action of the spring means (28) and only when the predetermined rotary opening position OL is reached do the disengagement and locking cam (36) and the cam engagement edge (38) under the action of the &bull; t * 4 i t t u 4 tons · * _* 3 u Spring means (28) forced return of the slider
(26) towards the home position into mutual locking, that the locking by manually triggered shifting
of the sliding piece (26) from the basic position
the action of the spring means (28) is releasable and that the pivoting sliding joint (18, 34) in the closing position ] position of the sash frame (10) can be disengaged | is that by disengaging the sliding piece (26) from \ its basic position against the effect of the spring f medium (28) the opening flap J30) opposite the I second frame leg (12a). I 2. Device according to claim 1, characterized in that the release and locking cam (36) has a release curve (36a) and adjacent to the release curve (36a) has a latch (36b). I 3. Device according to one of claims 1 and 2, characterized in that the pivoting sliding joint (18, 34) I is guided by a fork-like open sliding slot (18) of a \ fitting attached to the second frame leg (12a) part (16) and a slotted engagement bolt (34) on the J other end of the display tab (30). | 4. Device according to claim 3, characterized in that |J the display flap (30) is formed by two mutually parallel f lamellae (30a, 30b) which are connected to the one J end receiving the sliding piece (26) between them and | are connected at the other end by the slotted engagement bolt | (34), wherein the sliding slot (18) | t··· f · · t β &Lgr; 4* * having a rib (16) of the fitting part (16) attached to the second frame leg engages between the two slats (30a, 30b). 5i Device according to one of claims 1 to 4, characterized in that the sliding piece (26) is designed as a manually operable release tab (26a) at its end remote from the display tab (30). 6. Device according to one of claims 1 to 5, characterized in that the slide guide comprises an elongated housing (20) with a rectangular cross section, which, in the closed position of the sash frame (10), accommodates the projection tab (30) over its entire length and has an opening (22) in a longitudinal side wall (24) for the projection tab (30) to pass through. 7. Device according to claim 6, characterized in that an end edge (38) of the opening (22) close to the sliding piece (26) is designed as a cam engagement edge. 8. Device according to one of claims 1 to 7, characterized in that the sliding piece (26) can be locked in its basic position relative to the sliding piece guide (20), the extension tab (30) in the basic position of the sliding piece either assumes the parallel position to the associated first frame leg (10a) corresponding to the closed position of the sash frame (10) and is fixed in this parallel position by the interaction of the release curve (36a) with the cam engagement edge (38) ..4.&igr;*&uacgr;&mdash;Vüi*H _f W Or the sash tab (30) is immobilized in the predetermined rotary opening position of the sash frame (10) by the interaction of the latch (36b) with the cam engagement edge (38). 9. Device according to claim 8, characterized in that a grub screw (50), in particular with an Allen key, is provided in the sliding piece (26), which can be screwed into engagement with a corresponding opening (52) in the sliding piece guide (20). &Igr;&Ogr;* Device according to one of claims 1 to 9, characterized in that it is symmetrical with respect to a plane of symmetry perpendicular to the axes of the pivoting and pivoting sliding joints (32 and 18, 34). 11. Device according to one of claims 1 to 10, characterized in that the sliding piece guide (20) can be fastened to a sash frame leg (10a). 12. Device according to one of claims 1 to 11, characterized in that it is designed for subsequent attachment to an already fogged-up window, door or the like. 13. Device according to one of claims 1 to 12, characterized in that for guiding the sliding piece (26) and/or for restricting the movement of the sliding piece (26) and/or for spring support, a hollow rivet (42) is provided which penetrates the sliding piece guide (20) and the sliding piece (26), which has a fastening screw for fastening the sliding piece guide to · t * ·· II * · ii &igr; i &igr; t I I I I 11 I * « ti 111 ti I «til -111 * · Il »I It the respective frame leg. 14. Device according to one of claims 1 to 13, characterized in that the predetermined rotational opening position öC is an intermediate position between the closed position of the sash frame (10) and a fully opened position of the sash frame (1Ö)* /5. Device according to one of claims 1 to 14, characterized in that it can be mounted in different positions along the associated frame legs (10a^ 12a). 16. Device for fixing a sash frame (10) that can be rotated about a rotation axis (A-A) to a frame (12) in a rotary opening position (<*.), comprising a display tab (30) which is hinged at one end to a first (10a) of two associated frame legs (10a, 12a) of the sash frame (10) and the frame (12) by a pivot joint (32) and is connected at its other end to the second (12a) of these associated frame legs (10a, 12a) by a pivot-sliding joint (18, 34), and locking means (36, 38J) which maintain the setting of the opening tab (30) relative to the frame legs (10a, 12a) in a rotary opening position (oc) in the absence of external force, wherein the display bracket (30) can be uncoupled from one (12a) of the frame legs (10a, 12a), in particular according to one of claims 1 - 15, characterized in that that the swivel joint (32) is arranged on a sliding piece (26) which is movable in the longitudinal direction of a first frame leg (10a) in a sliding piece guide (20), that this sliding piece (26) is preloaded by spring means (28) towards a basic position, that the pivoting sliding joint (18, 34) is formed by a sliding slot (18) which is open at one end like a fork in a fitting part (16) fastened to the second frame leg (12a) and an Öhllitz engagement bolt (34) at the other end of the extension tab (30), that in the closed position of the sash frame (10) to the frame (12) the slot engagement bolt (34) lies within the sliding slot (18) with the sliding piece (26) in the basic position and that the slot engagement bolt (34) can be disengaged from the sliding slot (18) in the closed position of the sash frame (10) relative to the frame (12) by moving the sliding piece (26) against the action of the spring means (28) from the basic position into a decoupling position. 17. Device according to claim 16, characterized in that the display tab (30) is formed by two mutually parallel slats (30a, 30b) which are mounted at one end on the sliding piece (26) and are connected at the other end by the slot engagement bolt (34), wherein a rib (16a) having the sliding slot (18) of the fitting part (16) attached to the second frame leg (12a) engages between the two slats (30a, 30b). 18. Device according to one of claims 16 and 17, characterized in that the sliding piece (26) is designed as a manually operable release button (26a) at its end remote from the raising tab (30). 19. Device according to one of claims 16 to 18, characterized in that the slide guide comprises an elongated housing (20) with a rectangular cross-section, which, in the closed position of the sash frame (10), accommodates the projection tab (30) over its entire length and has an opening (22) in a longitudinal side wall (24) for the projection tab (30) to pass through. 20. Device according to one of claims 16 to 19, characterized > ·· · · The The &bull; > I · I I · i I 4 I I i ·«!* · * * III 9 - characterized in that it is symmetrical with respect to a symetrical drive plane perpendicular to the axes of the pivoting and pivoting-sliding joints (32 and 18, 34 respectively). 21. Device according to one of claims 16 to 20, characterized in that for guiding the sliding piece (26) and/or for limiting the movement of the sliding piece (26) and/or for supporting the spring means, a bolt passing through the sliding piece guide (20) and the sliding piece (26), in particular ^- special hollow rivet (42) is provided, which provides a fastening screw for fastening the sliding guide to the respective frame leg. 22. Device according to one of claims 16 to 21, characterized in that on the fitting part (16) adjacent to the open end of the sliding slot (18) there is a beveled edge (16b) is provided, which lies in the area of the slotted engagement bolt (34) when the sliding piece (26) is in the basic position. 23. Device according to one of claims 16 to 22, characterized characterized in that the sliding piece (26) in its basic S &zgr; position relative to the slide guide (20) can be locked. 24. Device according to claim 23, characterized in that in the sliding piece (26) a grub screw (50), in particular [ ore with Allen key, which engages with a corresponding opening (52) of the slide guide (20) can be screwed.