Padlock having a blocking plate for a spring-biased locking element

Abstract

A padlock including a lock body, a shackle having two shanks with grooves for receipt of respective locking elements, and a pin which can be rotated by a lock cylinder core for moving the locking elements into their locking position. The pin has an engagement element configured to cooperate with an entrainer formation on the lock cylinder core. The padlock also includes a blocking plate located between the pin and the lock cylinder core and which is fastened in the lock body. The blocking plate has an opening through which the entrainer formation projects into the plane of the engagement element. The opening is configured such that, on the one hand, rotational movement of the lock cylinder core is possible and, on the other hand, a marginal region of the opening forms an abutment engageable with the entrainer formation for restricting rotational movement of the lock cylinder core.

Claims

1. A padlock comprising: a lock body; a shackle with two shanks each having a groove for the reception of a part region of a corresponding locking element; a pin operable to be acted on by a lock cylinder core to make a rotational movement for moving the locking elements into a locked position, the pin having a jacket surface that includes a pair of oppositely disposed grooves as well as another groove having a depth greater than the pair of oppositely disposed grooves, and at least one engagement element configured to cooperate with at least one entrainer formation of the lock cylinder core; a spring biasing the pin into the locked position; a blocking plate located between the pin and the lock cylinder core that is fastened in the lock body and has an opening through which the entrainer formation of the lock cylinder core projects into a plane of the engagement element, with the opening being configured such that rotational movement of the lock cylinder core is possible and such that a marginal region of the opening forms an abutment that is engageable with the entrainer formation for restricting rotational movement of the lock cylinder core; and a selectively removable bridge member inserted between the engagement element and the entrainer formation, the bridge member operable to be inserted through the opening in the blocking plate into the plane of the engagement element; wherein the pin is arranged entirely outside a plane defined by the blocking plate, a core play exists between the engagement element and the entrainer formation that allows rotation of the lock cylinder core about a specific angle without the pin co-rotating, and the bridge member, when selectively inserted between the engagement element and the entrainer formation, eliminates the play.

2. The padlock in accordance with claim 1, wherein a first marginal region of the opening in the blocking plate forms another abutment engageable with the entrainer formation for restricting rotational movement of the lock cylinder core into an open position.

3. The padlock in accordance with claim 1, wherein the lock cylinder core has first and second entrainer formations that are arranged off-center on an end face facing the pin and that are oppositely disposed with respect to an axis of rotation of the lock cylinder core.

4. The padlock in accordance with claim 3, wherein the first and second entrainer formations each have a substantially rectangular cross-section.

5. The padlock in accordance with claim 3, wherein the first marginal region of the opening in the blocking plate forms a first abutment engageable with the first entrainer formation for restricting rotational movement of the lock cylinder core into an open position, and wherein a second marginal region of the opening in the blocking plate forms a second abutment engageable with the second entrainer formation for restricting rotational movement of the lock cylinder core into the locked position.

6. The padlock in accordance with claim 1, wherein the pin has first and second engagement elements which are arranged off-center on an end face of the pin facing the lock cylinder and which are oppositely disposed with respect to the axis of rotation of the pin.

7. The padlock in accordance with claim 6, wherein the first and second engagement elements each have a cross-section of substantially quadrant shape.

8. The padlock in accordance with claim 1, wherein the blocking plate is pressed into the lock body.

9. The padlock in accordance with claim 1, wherein the blocking plate has a circular shape with a diameter that corresponds to a diameter of a region of a lock cylinder that includes the lock cylinder core.

10. The padlock in accordance with claim 1, wherein the blocking plate includes an outer periphery having elevated portions and recesses in an alternating fashion in at least a part thereof.

11. The padlock in accordance with claim 1, wherein the blocking plate includes an outer periphery having a security against rotation member projecting radially therefrom.

12. The padlock in accordance with claim 1, wherein the opening in the blocking plate approximately has the shape of a part circle, with the part circle including an angle between 180 and 300.

13. The padlock in accordance with claim 1, wherein the shanks of the shackle have different lengths, and the shank having a greater length has a restriction at an end region that faces the lock body.

14. The padlock in accordance with claim 1, wherein the bridge member has a Z shape with a center part and two shanks projecting therefrom at an angle.

15. The padlock in accordance with claim 14, wherein marginal regions of the shanks of the bridge member are outwardly disposed with respect to the center part and have the shape of an arc of a circle, with a radius of these arcs being smaller than the radius of the opening of a part circle portion of the blocking plate.

16. The padlock in accordance with claim 1, wherein a center part has a chamfer in the region of only one of the two shanks which is provided on the side of the center part remote from the respective shank.

17. A padlock comprising: a lock body; a shackle with two shanks each having a groove for receipt of a respective part region of a locking element; a pin configured to be acted on by a lock cylinder core to make a rotational movement for moving the locking elements into a locked position, the pin being biased into the locked position by a spring, and the pin having at least one engagement element configured to cooperate with at least one entrainer formation on the lock cylinder core; a blocking plate provided between the pin and the lock cylinder core fastened in the lock body and having an opening through which the entrainer formation of the lock cylinder core projects into a plane of the engagement element, with the opening being configured such that a rotational movement of the lock cylinder core is possible and such that a marginal region of the opening forms an abutment engageable with the entrainer formation for restricting rotational movement of the lock cylinder core; and a selectively removable bridge member inserted between the engagement element and the entrainer formation, the bridge member operable to be inserted through the opening in the blocking plate into the plane of the engagement element; wherein the pin is arranged entirely outside a plane defined by the blocking plate and has, at jacket surface thereof, a pair of oppositely disposed grooves and another groove having a depth greater than a depth of the pair of oppositely disposed grooves, and wherein a core play is present between the engagement element and the entrainer formation that allows rotation of the lock cylinder core about a specific angle without the pin co-rotating, and the bridge member, when selectively inserted between the engagement element and the entrainer formation, eliminates the play.

18. The padlock in accordance with claim 17, further including a tool having a T shape in a front end region with the length of a transverse shank of the T shape being dimensioned such that the transverse shank is movable through the opening of the blocking plate, and wherein the dimensions of the transverse shank in a direction of an axis of rotation of the cylinder core corresponding approximately to a height of at least one of the engagement elements of the pin wherein a connection section between the transverse shank and a remaining tool region is dimensioned such that this connection section is rotatable within the opening of the blocking plate.

19. The padlock in accordance with claim 18, wherein a cylindrical region whose diameter is dimensioned larger than a diameter of the cylinder core adjoins the front end region.

Description

DRAWINGS

(1) The invention will be explained in the following by way of example with reference to the drawings; there are shown in these:

(2) FIG. 1 is an exploded drawing of a padlock in accordance with the invention viewed obliquely from above;

(3) FIG. 2 is a drawing of the padlock in accordance with FIG. 1 viewed obliquely from below;

(4) FIG. 3 is a bottom view of a lock body associated with the padlock shown in FIGS. 1 and 2 without a lock cylinder, a bridge member, a blocking plate or a spring;

(5) FIG. 4 is a view similar to FIG. 3 with the exception that the spring has been installed in the lock body;

(6) FIG. 5 is a view similar to FIG. 3 with the exception that the spring and the blocking plate have been installed in the lock body;

(7) FIG. 6 is a view similar to FIG. 3 but showing the lock body having the spring, the blocking plate and an entrainment member of the lock cylinder core;

(8) FIG. 7 is a partial sectional side view of a completely assembled padlock in accordance with FIGS. 1 and 2 in its locked state;

(9) FIG. 8 is a view similar to FIG. 6 with the entrainment member of the lock cylinder core rotated;

(10) FIG. 9 is a partial sectional side view similar to FIG. 7 in which the padlock is shown in its open state;

(11) FIG. 10 is a view similar to FIG. 8 showing the entrainment member of the lock cylinder core rotated back to the position shown in FIG. 6;

(12) FIG. 11 is a view similar to FIGS. 8 and 10 without the entrainment member, but showing an insertable bridge member;

(13) FIG. 12 is a view similar to FIG. 11 showing the entrainment member of the lock cylinder core;

(14) FIG. 13 is a view in accordance with FIG. 12 showing a rotated lock cylinder core;

(15) FIG. 14 is a freely sectioned view of a padlock in accordance with the invention with an introduced tool in a first position;

(16) FIG. 15 is a view in accordance with FIG. 14 with the introduced tool in a second position; and

(17) FIG. 16 is a schematic representation of a side view of the front region of the tool in accordance with FIGS. 14 and 15.

DETAILED DESCRIPTION

(18) The following description is merely exemplary in nature and is not intended to limit the present invention and its applications and/or uses.

(19) FIGS. 1 and 2 show a padlock having a lock body 2 which has two bores 4 at its upper end face into which two shanks 6, 8 of a shackle 10 can be introduced. The shank 6 is in this respect longer than the shank 8 and, when it is in the lock body 2, is biased by a compression spring 12 which moves the shackle 10 axially into its unlocked open position if it is not held back by other forces.

(20) Both shanks 6, 8 of the shackle 10 each have a groove 14 at the same height formed in their inner side and into which a respective part region of a locking element, shown herein as a locking ball 16, engages in the locked state of the padlock. Instead of locking balls 16, locking elements shaped in any other suitable manner can also alternatively be used. The longer shank 6 furthermore has a restriction 68 between its end at the lock body side and its groove 14, with the restriction preferably extending over the total periphery of the shank 6. Alternatively, it would also be possible here only to provide a notch or groove on the side of the longer shank 6 facing the locking ball 16. Such a notch or groove would then not extend over the total periphery of the shank 6.

(21) At its lower end face and disposed opposite the bores 4, the lock body 2 has two mutually overlapping bores 18 which are dimensioned such that a lock cylinder 20 can be introduced into them from below. This lock cylinder 20 can be fastened in a usual manner in the lock body 2 by means of a screw 22 with an open shackle 10.

(22) Upon the assembly of a padlock in accordance with FIGS. 1 and 2 ex works, the following describes a preferred order that the parts are first introduced into the lock body 2 via the bores 18 before introduction of the lock cylinder 20.

(23) After the locking balls 16 have been inserted into the lock body 2, a lock pin, shown herein as a ball pin 24, is inserted which substantially has a cylindrical shape and has, at its outer periphery, two mutually oppositely disposed grooves 26 which form a control gate for the locking balls 16 in the usual manner. Upon rotation of the ball pin 24 about its center axis, the named control gate is able to move the locking balls 16 between their locking position into the grooves 14 of the shackle 10 and their releasing position out of the grooves 14.

(24) The ball pin 24 furthermore also has an additional groove 26a at its outer periphery whose radial depth is dimensioned larger than that of the mutually oppositely disposed grooves 26. The operation of the additional groove 26a will be explained hereinafter.

(25) At its lower side, the ball pin 24 has two originally-extending engagement elements 28, 28 which are quadrant-shaped in cross-section and which are arranged symmetrical to the central axis of rotation of the ball pin 24.

(26) After insertion of the ball pin 24 into the bores 18, a spiral spring 30 is inserted such that its inwardly projecting prolongation 32 is supported at the engagement element 28 and its outwardly projecting prolongation 34 is fixed in the lock body 2 in a suitable manner to inhibit movement relative to the lock body 2. A rotational movement of the ball pin 24 in a clockwise movement (with respect to FIG. 2) consequently produces an entrainment of the prolongation 32 by the engagement element 28 and thus causes a tensioning of the spiral spring 30.

(27) After insertion of the spiral spring 30, a blocking plate 36 in accordance with the invention is introduced into the openings 18 and is pressed therein so that it can no longer move relative to the lock body 2. The pressing takes place in this respect at a position in which a tensioning or relaxation of the spiral spring 30 is not impeded by friction. The blocking plate 36 has a security against rotation projection or tab 38 which protrudes radially beyond its periphery and which reliably prevents rotation of the blocking plate 36 about the axis of rotation of the ball pin 24 when the blocking plate 36 is pressed into the lock body 2. The blocking plate 36 furthermore has a central opening 40 which approximately has the shape of a part circle, with the part circle including an angle of approximately 240. A region 42 of the blocking plate 36 which is not associated with the opening 40 and which would complement the opening 40 to form a full circle accordingly approximately includes an angle of 120, with the tip of this region 42 being disposed somewhat outside the center of the opening 40 in the radial direction so that the opening 40 does not form an exact part circle, but is rather made somewhat larger than such an exact part circle.

(28) After insertion of the blocking plate 36, a bridge member 44 can be inserted as required through the opening 40 in the blocking plate 36 in the manner explained below and ultimately comes to lie between the engagement elements 28 and 28. The bridge member 44 substantially has a Z shape with a center part 46 and two shanks 48, 48 projecting therefrom at right angles.

(29) As required, the bridge member 44 is typically first coupled with the lock cylinder 20 and then inserted into the lock body 2 together with it. A rotatable cylinder core 50 of the lock cylinder 20 has, at its end face facing the ball pin 24, a substantially U-shaped entrainment member 52 which defines two entrainer formations 54, 54 that project axially in the direction of the ball pin 24 (see FIG. 1). The two entrainer formations 54, 54 have a substantially square cross-section and define a gap between them in which the center part 46 of the bridge member 44 can be received so that in this case the bridge member 44 rotates together with entrainer formations 54, 54 after insertion of the lock cylinder 20 upon rotational movement of the cylinder core 50.

(30) After the insertion of the lock cylinder 20, it is fixed in the lock body 2 by means of the screw 22, whereupon the padlock is completely assembled. As required, the lock cylinder 20 can be easily removed from the lock body 2 again by loosening the screw 22 in the unlocked position of the padlock. An optionally inserted bridge member 44 can then likewise be removed to convert the padlock from forced locking to an automatic operation. The lock cylinder 20 can equally naturally also be removed to insert a bridge member 44, not previously present, through the opening 40 in the blocking plate 36 in order to carry out a conversion of the padlock from an automatic operation to forced locking. On such conversion processes, the spiral spring 30 and also the ball pin 24 cannot fall out of the lock body 2 since they are retained therein by the blocking plate 36 in accordance with the invention.

(31) FIG. 3 shows a bottom view of the lock body 2 in accordance with FIGS. 1 and 2, with a further small bore 56 provided in the region of the bores 18 and with the screw 22 for the fixing the lock cylinder 20 being screwed through the small bore 56 into a threaded bore 59 (see FIG. 1) formed in the upper end face of the lock cylinder 20. FIG. 3 furthermore shows the lower end face of the ball pin 24 with its two engagement elements 28, 28.

(32) If, in accordance with FIG. 4, the spiral spring 30 is introduced into the bores 18, care must be taken that the inner prolongation 32 of the spiral spring 30 is supported at the engagement element 28 so that a clockwise movement of the ball pin 24 produces an entrainment of the prolongation 32 by the engagement element 28. The outer prolongation 34 of the spiral spring 30 is fixed in a corresponding groove 58 formed in the lock body 2 that is sized so that outer prolongation 34 can either not move at all or can only move slightly in the lock body 2.

(33) After insertion of the spiral spring 30, in accordance with FIG. 5, the blocking plate 36 is introduced into the bores 18. The blocking plate 36 in the embodiment in accordance with FIG. 5 has at its outer periphery a serrated or toothed arrangement 60 which enables a particularly good pressing of the blocking plate 36 into the bores 18. The opening 40 of the blocking plate is made as already explained in connection with FIGS. 1 and 2.

(34) The radially projecting security against rotation tab 38 of the blocking plate 36 extends into the same groove 58 into which the outwardly projecting prolongation 34 of the spiral spring 30 was already introduced. Both rotation of the blocking plate 36 and rotation of the outer prolongation 34 of the spiral spring 30 relative to the lock body 2 is therefore reliably prevented by this engagement within the groove 58.

(35) If subsequently, the lock cylinder 20 is now introduced into the bores 18without the previous setting on of a bridge member 44the entrainer formations 54, 54 and thus the entrainment member 52 move at least partly into the plane of the spiral spring 30 and the engagement elements 28, 28. Since the engagement elements 28, 28 and the entrainer formations 54, 54 extending through the opening 40 lie at least partly in the same plane, they can abut one another upon rotational movement of the cylinder core 50 of the lock cylinder 20 so that a rotational movement of the cylinder core 50 can be transmitted to the ball pin 24.

(36) If the cylinder core 50 is located in its locked position whereat an introduced key can be withdrawn, the entrainment member 52 is located in its position shown in FIG. 6 such that the spiral spring 30 biases the engagement element 28, 28 on the ball pin 24 toward the entrainer formations 54, 54 on the entrainment member 52. In this position, in accordance with FIG. 7, the locking balls 16 are in engagement with an outer jacket surface of ball pin 24 and the grooves 14 of the shackle 10, whereby movement of the locking balls 16 out of the grooves 14 is blocked by the ball pin 24. Note that compression spring 12 is compressed by the end of shank 6. The padlock is thus reliably locked in this position.

(37) If thereafter the cylinder core 50 is rotated by means of the key starting from the position shown in FIG. 6 in the direction of the arrow shown in FIG. 8, the entrainment member 52 accordingly also rotates and causes the entrainer formations 54, 54 to engage and rotate the corresponding engagement elements 28, 28 while increasing the bias of the spiral spring 30. The ball pin 24 is thus rotated about the same angular range as the cylinder core 50.

(38) As shown in FIG. 9, the mutually oppositely disposed grooves 26 in the ball pin 24 in this manner are rotated into the region of the locking balls 16, thereby enabling an inward movement of the locking balls 16 so that they can be moved out of the grooves 14 in the shackle 10. As a result, the compression spring 12 relaxes and moves the shank 8 of the shackle 10 completely out of the lock body 2. A region of the longer shank 6, however, remains in the lock body 2 since it is restricted in its axial movement by its corresponding locking ball 16 engaged with restriction 68.

(39) In this opened position of the padlock, the entrainment member 52 abuts a first abutment surface 62 associated with region 42 of the blocking plate 36 so that the blocking plate ultimately restricts movement of the entrainment member 52 into its unlocked position. Likewise, a second abutment surface 64 associated with region 42 of blocking plate 36 (FIG. 6) ultimately restricts movement of the entrainment member 52 into its locked position in a corresponding manner.

(40) FIG. 8 shows that there is an area of play between the entrainment member 52 or its entrainer formations 54, 54 and the engagement elements 28, 28 which makes it possible that the entrainment member 52 starting from the position shown in FIG. 8 can be rotated back into the position shown in FIG. 6 without the engagement elements 28, 28 or the ball pin 24 concurrently moving in this respect. This position is shown in FIG. 10. In this position, the padlock is still in its open state in accordance with FIG. 9, with it, however, being possible to withdraw the key from the lock cylinder core 20 since the cylinder core 50 is again in its locked position in accordance with FIGS. 6 and 7 independently of the ball pin 24.

(41) If now, starting from the positions FIG. 8 or FIG. 10, the shackle 10 is pressed into the lock body 2, the spiral spring 30 has the effect that the ball pin 24 rotates such that it moves into its position in accordance with FIGS. 6 and 7, with the locking balls 16 simultaneously being outwardly displaced into the grooves 14. In this position, the padlock is then again locked without there being any need for the conveying into this locked state of the key.

(42) FIGS. 3 to 10 thus describe an automatic operation of the padlock in accordance with the invention. This automatic operation is realized since no bridge member 44 has been inserted into the plane of engagement elements 28, 28 or entrainer formations 54, 54.

(43) FIG. 11 now shows a situation in which the ball pin 24 is located in its unlocked position in accordance with FIG. 8 so that the opening 40 of the blocking plate 36 is reduced exclusively by the one engagement element 28 of the ball pin 24 since the other engagement element 28 is located behind the region 42 of the blocking plate 36. The opening 40 of the blocking plate 36 made smaller by the engagement element 28 is in this respect sufficiently large that the bridge member 44 can be moved through this opening 40 until it is located in the plane of the engagement elements 28, 28. As already explained, the bridge member 44 has a center part 46 from which two shanks 48, 48 project at right angles. The two marginal regions of the shanks 48, 48 disposed outwardly with respect to the center part 46 have the shape of an arc of a circle, with the radius of these arcs being smaller than the radius of the opening 40 of the blocking plate 36. The center piece 46 has a chamfer 66 in the region of the shank 48 so that the bridge member 44 does not abut the abutment surface 64 of the blocking plate 36 on its insertion which, as a rule, occurs together with insertion of the lock cylinder 20.

(44) After the lock cylinder 20 with the bridge member 44 located between its entrainer formations 54, 54 in accordance with FIG. 11 has been inserted in the open position of the padlock (FIG. 9), the lock cylinder 20 can be screwed to the lock body 2 via the screw 22. Since the coupling of the bridge member 44 to the lock cylinder 20 takes place before insertion of the lock cylinder 20, the entrainment member 52 moves into its position shown in FIG. 12 in which the entrainer formations 54, 54 come to lie at both sides of the center part 46 of the bridge member 44.

(45) FIG. 12 shows in a very illustrative manner that with a lock cylinder 20 inserted into the lock body 2, the two shanks 48, 48 of the bridge member 44 largely eliminate the play between the entrainment member 52 and the engagement elements 28, 28 so that the entrainment member 52 cannot be rotated in the direction of the arrow in accordance with FIG. 12 without in this respect entraining the engagement elements 28, 28 of the ball pin 24. In this respect, a rotation of the cylinder core 50 or of the entrainment member 52 in the direction of the arrow in accordance with FIG. 12 necessarily has the result that the ball pin 24 is also rotated into its locked position. Such a rotation is, however, only possible after the shackle 10 has been completely inserted into the lock body 2 so that a key can only be withdrawn from the cylinder core 50 when the padlock is actually locked. The position of the components shown in FIG. 12 after rotation in the direction of the arrow is shown in FIG. 13. Both the entrainment member 52 and the engagement elements 28, 28 and thus the ball pin 24 are located in their locked position in accordance with FIG. 13, whichas already mentionedhas the effect that the total padlock is in its locked position in accordance with FIG. 7.

(46) FIG. 14 shows the padlock in accordance with FIGS. 1 to 13 in a cut-away representation without the lock cylinder 20. In this respect, the ball pin 24 is in such a position that the locking balls 16 engage into the two mutually oppositely disposed grooves 26 (see FIG. 1) so that the locking balls 16 release the grooves 14 on the shanks 6, 8 of the shackle 10, which has the effect that the shackle 10 is moved out of the lock body 2 by the compression spring 12, as is shown in FIG. 14. The locking ball 16 at the right in FIG. 14 is in this respect in engagement with the restriction 68 of the longer shank 6 of the shackle 10 and thus prevents this longer shank 6 from being able to be completely released from the lock body 2.

(47) The padlock in accordance with the invention is shown in FIG. 14 after the lock cylinder 20 (FIG. 1) has been removed from the lock body 2. Instead of the lock cylinder 20, a tool 70 is now introduced into the bores 18the lock body 2 provided for the lock cylinder 20 in accordance with FIG. 14.

(48) The front end region of the tool 70 is shown schematically in FIG. 16. It has a cylindrical section 72 whose diameter is dimensioned somewhat larger than the diameter of the lock cylinder core 50 (FIG. 1) so that this cylindrical section 72 is easily guided or supported in the lock body 2. The cylindrical section 72 tapers in its front end region and merges into a T-shaped section 74 which has a transverse shank 76 which extends transversely to the longitudinal axis of the tool 70.

(49) This transverse shank 76 is conducted so far through the opening 40 of the blocking plate 36 in accordance with FIG. 14 until the end regions of the transverse shank 76 are in contact with the engagement elements 28, 28 of the ball pin 24. Starting from this position shown in FIG. 14, the tool 70 can be rotated clockwise so that the ball pin 24 co-executes this rotation and is overrotated. This overrotation has the result that the deeper groove 26a (FIG. 1, FIG. 14) of the ball pin 24 moves into engagement with the locking ball 16 shown at the right in FIGS. 14 and 15. As FIG. 15 shows, this locking ball 16 can then move inwardly so far in the lock body 2 that it releases the restriction 68 so that the longer shank 6 of the shackle 10 can be completely moved past the locking ball 16 and can be removed from the lock body 2.

(50) In the tool position shown in FIG. 15, another shackle 10 can then be introduced as required into the lock body 2. If the tool is subsequently rotated back again counterclockwise into the position in accordance with FIG. 14, the locking ball 16 shown at the right in FIG. 14 or 15 in turn prevents, due to a restriction 68 also present in the new shackle, said shackle from being released unintentionally from the lock body 2.

(51) FIGS. 1 to 15 thus show a padlock in accordance with the invention which simultaneously permits both a replacement of the shackle and a switch between an automatic operation and forced locking and in this respect provides the advantages in accordance with the invention.

REFERENCE NUMERAL LIST

(52) 2 lock body 4 bores 6 shank 8 shank 10 shackle 12 compression spring 14 groove 16 locking ball 18 bores 20 lock cylinder 22 screw 24 ball pin 26 grooves 26a deeper groove 28, 28 engagement element 30 spiral spring 32 prolongation 34 prolongation 36 blocking plate 38 security against rotation 40 opening 42 region 44 bridge member 46 center part 48, 48 shank 50 cylinder core 52 entrainment member 54, 54 entrainer formation 56 bore 58 groove 59 thread 60 toothed arrangement 62 abutment surface 64 abutment surface 66 chamfer 68 restriction 70 tool 72 cylindrical tool section 74 front end region 76 transverse shank

(53) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.