Fastener element for a fastening system, fastening tool, disengagement and testing of a fastener element, method for providing a fastening system with a closure seal and/or a torque indicator

Abstract

The instant invention relates to a fastener element of a fastening system, a tool for fastening, disengaging and testing the fastener element and a method for providing a fastening system with a closure seal and/or a torque indication. The fastener element of a fastening system, in particular a bolt or nut includes a tool engagement surface that is engageable by a tool, in particular a standard tool for at least partial form locking contact with the tool for fastening or disengaging the fastening system, wherein the tool engagement surface includes at least one weak spot. The fastener element is operable with standard tools and optionally reusable using special tools. Thus, manipulations by unauthorized persons are easily detectable and it is easily determinable whether a predetermined torque has been applied correctly.

Claims

1. A fastener element of a fastening system, the fastener element comprising: a tool engagement surface that is engageable by a tool for at least partial form locking contact with the tool for fastening or disengaging the fastening system, wherein the tool engagement surface includes at least one weak spot which facilitates a deformation of the weak spot or at least a deformation or weakening of a portion adjacent to the weak spot when a particular torque is imparted from the tool to the tool engagement surface which indicates an unauthorized use or an authorized use with a sufficiently large torque, wherein the tool engagement surface is configured as a straight slot, or cross slot, or external polygon, or internal polygon, or external involute, or internal involute, or Ribe, or Torx, or Tri-Wing, or Torq-Set, or Torx-Tamper or Pentalob, and wherein the tool is a straight slot, or cross slot, or external polygon, or internal polygon, or external involute, or internal involute, or Ribe, or Torx, or Tri-Wing, or Torq-Set, or Torx-Tamper or Pentalob tool.

2. The fastener element according to claim 1, wherein the tool engagement surface includes plural portions, and wherein at least one portion or at least half of a number of the plural portions is provided with at least one weak spot.

3. The fastener element according to claim 1, wherein the weak spot is arranged at or proximal to a section of a portion where a main force is transferred from the tool to the tool engagement surface when the tool is used correctly.

4. The fastener element according to claim 1, wherein the weak spot is symmetrically arranged with respect to a symmetry of the tool engagement surface.

5. The fastener element according to claim 1, wherein the weak spot is asymmetrically arranged with reference to a symmetry of the tool engagement surface.

6. The fastener element according to claim 1, wherein the weak spot is configured as a material recess or as a material variation.

7. A tool for fastening, disengaging and testing the fastener element according to claim 6, wherein the tool includes a tool operating surface corresponding to the tool engagement surface, and wherein the tool operating surface includes at least one surface section engaging the material recess.

8. The fastener element according to claim 1, wherein two different types of weak spots are provided.

9. The fastener element according to claim 1, wherein a first type of weak spot is provided which poses a first resistance against the tool operating surface during disengagement or fixation, and wherein the first type of weak spot is configured as a recess into which the tool operating surface penetrates during the disengagement or the fixation.

10. The fastener element according to claim 1, wherein a length of the weak spot along the tool engagement surface is equal to or greater than a length of an adjacent portion of the tool engagement surface.

11. The fastener element according to claim 1, wherein a second type of weak spot is provided which provides a second resistance for the tool operating surface during disengagement or fixation, wherein the second resistance is advantageously provided by a rated fracture area or a rated deformation area, and wherein the rated fracture area or the rated deformation area is formed by providing the second weak spot by an undercut.

12. The fastener element according to claim 1, wherein at least one parameter from the group consisting of number of weak spots, shape of weak spot, dimension of the weak spot, use of various types of weak spots and dimension of the portion at which the main force is transferred from the tool to the tool engagement surface when the tool is used correctly is adjusted so that a deformation of the weak spot or of a portion adjacent to the weak spot is provided when a torque of a predetermined amount is applied.

13. A method for providing a fastening system with a fastening seal or a torque indication, comprising the steps: providing a fastener element of the fastening system-with a tool engagement surface that is engageable by a tool for at least partial form locking contact with the tool for fastening or disengaging the fastening system; providing the tool engagement surface with at least one weak spot which facilitates a deformation of the weak spot or at least a deformation or weakening of a portion adjacent to the weak spot; imparting a particular torque from the tool to the tool engagement surface; and indicating an unauthorized use or an authorized use with a sufficiently large torque, wherein the tool engagement surface is configured as a straight slot, or cross slot, or external polygon, or internal polygon, or external involute, or internal involute, or Ribe, or Torx, or Tri-Wing, or Torq-Set, or Torx-Tamper or Pentalob, wherein the tool is a straight slot, or cross slot, or external polygon, or internal polygon, or external involute, or internal involute, or Ribe, or Torx, or Tri-Wing, or Torq-Set, or Torx-Tamper or Pentalob tool.

14. The method according to claim 13, comprising the step using a fastener element including: a tool engagement surface that is engageable by a tool for at least partial form locking contact with the tool for fastening or disengaging the fastening system, wherein the tool engagement surface includes at least one weak spot which facilitates a deformation of the weak spot or at least a deformation or weakening of a portion adjacent to the weak spot when a particular torque is imparted from the tool to the tool engagement surface which indicates an unauthorized use or an authorized use with a sufficiently large torque for fastening, disengaging and testing the fastener element.

15. The method according to claim 13, wherein the weak spot is configured as a material recess or as a material variation, wherein the tool includes a tool operating surface corresponding to the tool engagement surface, and wherein the tool operating surface includes at least one surface section engaging the material recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional features and advantages of the invention are described based on embodiments with reference to appended drawing figures, wherein identical and equivalent components are designated with identical reference numerals, wherein:

(2) FIGS. 1A, 1B illustrate a first advantageous embodiment of the fastener element according to the invention;

(3) FIGS. 2A, 2B illustrate a first advantageous embodiment of the tool according to the invention and the combination of this tool with the fastener element according to FIGS. 1A, 1B;

(4) FIGS. 3A, 3B illustrate a first standard tool and the combination of the fastener element according to FIG. 1A 1B with the first standard tool;

(5) FIGS. 4A, 4B illustrate a second standard tool and the combination of the fastener element according to FIGS. 1A, 1B with the second standard tool;

(6) FIGS. 5A, 5B illustrate a second advantageous embodiment of the fastener element according to the invention;

(7) FIGS. 6A, 6B illustrate a second advantageous embodiment of the tool according to the invention;

(8) FIGS. 7A, 7B illustrate a third advantageous embodiment of the fastener element according to the invention;

(9) FIGS. 8A, 8B illustrate a fourth advantageous embodiment of the fastener element according to the invention;

(10) FIGS. 9A, 9B illustrate a fifth advantageous embodiment of the fastener element according to the invention;

(11) FIG. 10 illustrates a combination of the fastener element according to FIGS. 9A, 9B with a third standard tool;

(12) FIGS. 11A, 11B illustrate a sixth advantageous embodiment of the fastener element according to the invention;

(13) FIG. 12 illustrates a combination of the fastener element according to the invention according to FIG. 10a, 10b with a third standard tool;

(14) FIG. 13A, 13B illustrates a seventh advantageous embodiment of the fastener element according to the invention;

(15) FIG. 14 illustrates an eighth advantageous embodiment of the fastener element according to the invention;

(16) FIGS. 15, 16 illustrate a ninth advantageous embodiment of the fastener element according to the invention;

(17) FIGS. 17A, 17B, 17C illustrate a tenth advantageous embodiment of the fastener element according to the invention;

(18) FIG. 18 illustrates an eleventh advantageous embodiment of the fastener element according to the invention; and

(19) FIG. 19 illustrates a twelfth advantageous embodiment of the fastener element according to the invention;

DETAILED DESCRIPTION OF THE INVENTION

(20) FIGS. 1A, 1B, 5A, 5B, 7A, 7B, 8A, 8B, 9A, 9B, 11A, 11B, 13A, 13B and 14-19 schematically illustrate fastener elements according to the invention wherein FIGS. 1A, 5A, 7A, 8A, 9A, 11A, 13A and 14-19 respectively illustrate top views of the drive and FIGS. 1B, 5B, 7B, 8B, 9B, 11B and 13B illustrate the associated perspective views.

(21) FIGS. 3A, 3B, 4A, 4B, 10 and 12 respectively illustrate combinations of fastener elements according to the invention with tools and thus in inserted condition of the tools into the respective fastener elements.

(22) FIGS. 1A, 1B illustrate a first fastener element according to the invention configured as a bolt 1 whose drive 3 has a tool engagement surface 5 which is configured as a hexagonal which includes a weak spot configured as a circular segment shaped material recess 9 in each of the six edges 7. This material recess 9 has an extension b of approximately 0.5 with respect to an edge length a, this means b/a is approximately 0.5. Thus, singular points 11 are formed which are loaded when using the drive 3 with a hexagonal wrench, wherein the loading is performed relative to the drive base element 13 with respect to shearing along a shearing line 15.

(23) The dimension of the weak spots formed as material recesses 9 and thus the dimension of the points 11 is thus selected so that the torques that are required for a disengaging or fixating a fastening provided by the screw 1 leads to a deformation or shearing in a portion of the points 11 or the transition between the points 11 and recesses 9 when a hexagonal Allen assembly wrench is used and not an assembly wrench whose tool operating surface provides full surface form locking along the tool engagement surface.

(24) A tool 17 according to the invention that is illustrated in top view in FIG. 2A for authorized use of the fastener element 1 includes a tool engagement surface 19 which exactly corresponds with the tool engagement surface 5 that is provided with the material recesses 9. This means when actuating the drive 3 with the tool 17 a full surface form locking contact is established between the tool operating surface 19 and the tool engagement surface 5 so that points 11 cannot be sheared off. During an authorized use of this type no deformation of the drive will occur (c.f. FIG. 2B).

(25) However, when one of the standard tools 21, 23 illustrated in FIGS. 3A 4A in top view is used wherein FIG. 3A illustrates an involute profile assembly wrench 21 and FIG. 4A illustrates a Torx assembly wrench, then the drive 3 of the bolt 1 according to FIG. 1A, 1B has no full surface form locking with the respective tool operating surfaces 25, 27 so that a shearing of the points 11 occurs when using the involute profile assembly wrench 21 and a deformation of the points 11 occurs when using the Torx assembly wrench 23. This shearing effect would for example also be observable when using a hexagonal wrench (also designated socket) which is not illustrated.

(26) FIGS. 5A, 5B illustrate a second fastener element according to the invention configured as a bolt 31, whose drive 33 illustrates a tool engagement surface 35 which is configured as an internal hexagonal and which includes a weak spot configured as a circular segment shaped material recess 39 in each of the six edges 37. This material recess 39 has an extension d of approximately 0.5 with respect to the edge length c, this means d/c is approximately 0.5. This forms singular double points 41 which are loaded with a hexagonal relative to the drive base element 43 in shearing 45 when using the drive 33.

(27) In order to prevent a deformation of this type a form locking special wrench 51 is used for unauthorized use of the drive 33 wherein the special wrench 51 includes corresponding circular segment shaped protrusions 55 corresponding to the material recesses 39 relative to a hexagonal 53 illustrated in FIG. 6A in a perspective view and in FIG. 6B in a top view.

(28) The fastener elements 1, 31 described supra include symmetrically introduced material recesses 9, 39 with respect to the tool engagement surfaces 5, 35. This would create deformations of the drive 5, 35 for each unauthorized use, this means during disengagement and also during fixation of the fastener element 1, 31.

(29) In FIGS. 7A, 7B, 8A, 8B, 9A, 9B, 11A and 11B respectively 3.sup.rd, 4.sup.th, 5.sup.th and 6.sup.th advantageous embodiments of the fastening dement 61, 63, 65, 67 according to the invention are shown in a top view of the respective drive 69, 71, 73, 75 or in a perspective view.

(30) Thus, the bolts 61, 63 illustrated in FIGS. 7A, 7B, 8A, and 8B are bolts whose drive 69, 71 has a tool engagement surface 71, 79 which is configured as an external hexagonal and which includes a weak spot configured as a material recess 85, 87 in each of the six edges 81, 83.

(31) The bolt 61 includes a semi-circular material recess 85 which is introduced clock wise from a center of the edge 81 towards a corner 89. With reference to the edge length e the material recess 85 has an extension f of approximately 0.25, this means f/e is approximately 0.25 Thus, symmetrical points 91 are configured which are loaded relative to the drive base element 93 in shearing when using the drive 69 counter clock wise with an Allen wrench but which are not deformed when using the drive 69 clock wise with an Allen wrench relative to the drive base element. This is caused by the fact that using the drive counter clock wise presses material of the point 91 into the material recess 85 which rounds the point 91.

(32) The bolt 63 according to FIG. 8A, 8B differs from the previously described bolt 61 according to FIG. 7A, 7B only in that the material recesses 87 are not only introduced in a semi-circular shape 85 but with angles. The effects with respect to an unauthorized use are the same as described for the bolt 61.

(33) The bolts 65, 67 illustrated in FIGS. 9A, 9B, 11A and 11B are bolts whose drive 73, 75 includes a tool engagement surface 97, 99 which is configured as an internal hexagonal and which includes a weak spot configured as a material recess 105, 107 in each of the six edges 101, 103.

(34) The bolt 65 includes semi-circular material recesses 105 which are introduced clockwise from a center of the edge 101 moved towards a corner 109. With respect to the edge length g each material recess 105 has an extension h of approximately 0.25, this means h/g is approximately 0.25. Thus, asymmetrically formed points 111 are formed which are loaded relative to the drive base element 113 in shearing 115 when using the drive 73 counter clockwise with a hexagonal (see FIG. 10), however when using the drive 73 clockwise with a hexagonal they are not deformed relative to the drive base element 113. This is caused by the fact that a counter clock wise use presses material of the point 111 into the material recess 105 which rounds the point 111.

(35) When as illustrated in FIG. 10 in top view the standard tool configured as an Allen wrench 117 is used for using the drive 73, then there is no full surface form locking engagement between the tool operating surface 119 and the drive 73 of the bolt 65 according to FIG. 9A, FIG. 9B so that a shearing or rounding of the points 11 will be provided when the drive 73 is rotated counter clockwise. However, when the rotation is performed clockwise then there is sufficient contact between the tool operating surface 119 and the drive 73 in the portions 121 so that no deformation occurs.

(36) The bolt 67 according to FIG. 11A, 11B differs from the bolt 65 according to FIG. 9A, 9B described supra only in that the material recesses 107 are not introduced in a semi-circular shape 105 but with angles. The effects with reference to unauthorized use (c.f. FIG. 12) are the same as described for the bolt 65.

(37) Thus, when the standard tool configured as an Allen wrench 117 as illustrated in FIG. 12 in top view is used for using the drive 75 then there is no full surface form locking between the drive 75 of the screw 67 according to FIG. 11A, 11B and the tool operating surface 119 so that a shearing or rounding of the points 123 is going to occur when the drive 75 is rotated counter clock wise. However, when a clock wise rotation is performed, then a sufficient contact between the tool operating surface 119 and the drive 75 is provided in the portions 125 so that no deformation is provided.

(38) FIGS. 13A, 13B illustrate a 7.sup.th advantageous embodiment of the fastener element 131 in top view and in a perspective view. It is evident that this is a bolt 131 with a drive 133 configured as an external hexagon. Thus, the weak spots 135 are generated in that the material recesses 87 of the bolt 63 of FIGS. 8A, 8B were subsequently filled again with the material 137 which has less hardness than the surrounding material 131. For example the material of the weak spot 137 is a plastic material and the remaining material is stainless steel. Then unauthorized use has the same effects as described for the screw 63 according to FIG. 8A, 8B.

(39) FIG. 14 illustrates an 8.sup.th advantageous embodiment of the fastener element 140 in top view. It is easily evident that this is a bolt 140 with a drive 141 in the form of an internal hexagonal. Thus, two different types of weak spots 145, 147 are provided with reference to the edges 143, namely a first type of weak spots 145 which is arranged directly at a corner of the internal hexagonal and a second type of weak spot 147 which is arranged offset from the corners of the inner hexagonal, wherein the weak spot, however, is not centrally arranged between two corners, but slightly closer towards a corner 149.

(40) This particular embodiment with two differently configured types of weak spots 145, 147 is selected when only small tightening torques can be used for smaller fastener elements 140 since there is a risk of damaging the fastener element 140 otherwise. Then material deformation occurs at the point 151 upon unauthorized use. In order for this material deformation to safely occur also for lower tightening torques fewer, namely advantageously two material deformations 147 of the second type and more, namely advantageously four material deformations 145 of the first type are used. Typically certainly also fewer material deformations 147 of the second type can be used depending on which tightening torques are tolerated by the fastener element 140.

(41) FIGS. 15 and 16 show a 9.sup.th advantageous embodiment of the fastener element 160 in top view. It is evident that this is a bolt 160 with a Torx drive 161, thus also two different types of weak spots 163, 165 are provided, namely a first type of weak spot 163 which is arranged directly adjacent to a corner of the Torx tool engagement surface 171 and a second type of weak spot 165 is provided which is configured as an undercut with respect to the tool engagement surface 171 so that a protrusion 167 is obtained which includes the tool operating surface 169. It is evident from FIG. 15 that in fixation direction F the tool operating surface 169 with its sections 169a transmitting the main force is applied to the drive 161 with its entirety to the tool operating surface 171. Thus, the maximum force can be transferred during fixation.

(42) It is evident from FIG. 16 that the tool operating surface 169 transferring the main force penetrates in disengagement direction L with its sections 169b almost everywhere into recesses of the weak spots of the first type 163, but contacts the surface 173 of the protrusion 167 partially. Due to the undercut 165 the protrusion 167 forms a rated fracture area or rated deformation area. When applying a force in the disengagement direction L wherein the force is required for disengaging the fastener element 160 the protrusion 167 is apparently sheared off by the tool operating surface 169 until the sections 169b that transmit the main force have completely penetrated into the recesses 163 or the shearing and deformation forces upon the protrusion 167 are greater than the forces used for disengagement. During disengagement the tool 175 has a propensity to penetrate the recesses of the weak spots 163 of the first type and is only prevented from doing so by the protrusion 167 forming a resistance, wherein the protrusion, however, is sheared off or at least deformed by the forces used for disengagement. The exact effect can be determined by a length and width of the protrusion 167 and by a number of the protrusions 167.

(43) FIGS. 17A, 17B and 17c illustrates a tenth advantageous embodiment of the fastener element 180 according to the invention in top view. It is evident that this is a bolt 180 with an internal hexagonal drive 181. Thus, also two different types of weak spots 184, 185 are provided, namely a first type of weak spot 183 which is arranged as a recess directly adjacent to a corner 187 of the inner hexagonal tool engagement surface 189 and a second type of weak spot 185 which is configured as a recess that is arranged offset from the corner 187a by the distance.

(44) It is apparent from FIG. 17B that the portions 191 of the tool operating surface 193 of the tool 194 which transfer the main force during disengagement L contact the portions 195 of the tool engagement surface 189 with their full surface so that the force required for disengagement can be transferred and no deformation is required.

(45) It is apparent from FIG. 17c that only the portion 191 out of the portions of the tool operating surface 193 which transfer the main force during fixating F contacts the protrusion 197. Due to the recess 185 the protrusion 197 forms a rated fracture area or a rated deformation area. When applying a force in the fixation direction F which force is required for fixating the fastener element 180 the protrusion 197 is apparently sheared off when the force imparted upon the protrusion 197 by the applied torque is greater than it's shearing or deformation force. When the shearing or deformation force is adjusted so that a desired torque has to be applied in order to cause the shearing or deformation then an indication of an applied torque of a sufficient amount is provided in the sense of a torque seal. Setting the desired torque can be determined in turn by the length and width of the protrusion 197 and the shape of the recess 185 and the number of such protrusions 197.

(46) In order to exclusively provide a shearing or deformation of the protrusion 197 and no deformation of the remaining tool engagement surface 189 a length m of the weak spot 183 of the first type on the tool engagement surface 189 is selected exactly as long as a length l of the adjacent portion of the tool engagement surface 189. Thus, a folding of the tool operating surface 193 relative to point 199 is provided during fixation. Thus, the length m can also be selected longer for this purpose.

(47) In this embodiment the first weak spot 183 is configured rounded. Thus, it has a shape so that a shearing or deformation is provided by the tool operating surface 193 in the recess 183 (not illustrated in FIG. 17c). Thus, a deformation or shearing of the protrusion 197 is provided and also a deformation of the recess 183. In order to prevent the latter the recess 183 would be configured corresponding to the tool operating surface 193 so that the tool operating surface 193 contacts the recess 183 flat in a folded over condition.

(48) FIG. 18 illustrates and eleventh advantageous embodiment of the fastener element 200 in top view. It is evident that this is essentially a drive 201 with an inverted configuration compared to the fastener element 180. Thus, a shearing or deformation of the protrusion 209 formed by the weak spot 205 of the second type is formed when the warranty seal is disengaged and the tool operating surface in turn has a propensity to penetrate the recess of the weak spot 203 of the first type. Furthermore an additional weak spot 207 of the second type is provided wherein the protrusion 209a formed by the weak spot 207 is slightly larger than the protrusion 209 since the length s is greater than the length r. The different protrusions facilitate to define the indicated torques more precisely in particular for torque seals, for example when particular protrusions to be fabricated are out of tolerance ranges that can be implemented through fabrication.

(49) This combination of different weak spots of the second type can also be used for torque seals for example when an inverted configuration of the drive 201 from FIG. 18 is used. Thus the torques for warranty seals can also be defined more precisely.

(50) As a matter of principle also a combination of warranty seal and torque seal is useful, for example a torque seal according to FIGS. 17A and 17c is provided in fixation direction F and in disengagement direction L for example a protrusion according to FIG. 15. A combination of this type is provided in principle already with the bolt 31 according to FIG. 5A, 5B, wherein the recess 39 would not be arranged symmetrically but asymmetrically in order to define tightening and disengagement torques precisely.

(51) An embodiment of this type is illustrated in FIG. 19. A bolt 220 with an internal hexagonal drive 221 is shown, wherein the drive 221 includes weak spots of the first type 223a, 223b and weak spots of the second type 225a, 225b that are respectively arranged mirror symmetrical with respect to a mirror plane S, wherein the weak spots are respectively provided in the form of recesses, wherein the weak spots of the second type 225a, 225b respectively form protrusions 227a, 227b which act against the tool 229. This particular embodiment causes a penetration of the tool operating surface 231 into the weak spots of the first type 223a in disengagement direction L and the weak spots of the second type are 223b in the fixation direction, wherein the protrusions 227b have to be overcome as a resistance in the disengagement direction and the protrusions 227a have to be overcome as resistances in the fixation direction.

(52) It is appreciated that all drawn shear lines are not actual body lines but are only drawn for illustration purposes.

(53) Unless stated differently all features of the instant invention can be combined with each other freely. Also the features described in the figure description unless stated differently can be freely combined with other features of the invention. Thus, device features can also be used as method features and method features can be used as device features.

(54) It has become apparent that the instant invention renders manipulations by unauthorized persons detectable in a very simple and cost effective manner for fastener elements of a fastening system or it can be determined very easily whether a particular predetermined torque was correctly used for fastener elements of a fastening system.

REFERENCE NUMERALS AND DESIGNATIONS

(55) 1 bolt

(56) 3 drive

(57) 5 tool engagement surface

(58) 7 edges

(59) 9 material recess

(60) a edge length

(61) b extension

(62) 11 points

(63) 13 drive base element

(64) 15 shear off line

(65) 17 tool

(66) 19 tool operating surface

(67) 21, 23 standard tools

(68) 25, 27 tool operating surface

(69) 31 bolt

(70) 33 drive

(71) 35 tool engagement surface

(72) 37 edges

(73) 39 material recess

(74) c edge length

(75) d extension

(76) 41 twin points

(77) 43 drive base element

(78) 45 shear off line

(79) 51 special wrench

(80) 53 hexagonal

(81) 55 protrusions

(82) 61, 63, 65, 67 fastener element

(83) 69, 71, 73, 75 drive

(84) 77, 79 tool engagement surface

(85) 81, 83 edges

(86) 85, 87 material recess

(87) 89 corner

(88) e edge length

(89) f extension

(90) 91 point

(91) 93 drive base element

(92) 95 shear off line

(93) 97, 99 tool engagement surface

(94) 101, 103 edge

(95) 105, 107 material recess

(96) 109 corner

(97) g edge length

(98) h extension

(99) 111 point

(100) 113 drive base element

(101) 115 shear off line

(102) 117 Allen wrench

(103) 119 tool operating surface

(104) 121 portion

(105) 123 point

(106) 125 portion

(107) 131 fastener element

(108) 133 drive

(109) 135 weak spot

(110) 137 filling material

(111) 140 fastener element

(112) 141 drive

(113) 143 edge

(114) 145 material recess

(115) 147 material recess

(116) 149 corner

(117) 151 point

(118) 160 bolt

(119) 161 Torx drive

(120) 163, 165 weak spot

(121) 167 protrusion

(122) 169 tool operating surface

(123) F fixation direction

(124) 169a main force transferring sections of tool operating surface 169

(125) L disengagement direction

(126) 169b main force transferring section of tool operating surface 169

(127) 171 Torx tool engagement surface

(128) 173 surface of protrusion 167

(129) 175 tool

(130) 180 bolt

(131) 181 internal hexagon drive

(132) 183, 185 weak spots, recesses

(133) 187 corner of inner hexagonal tool engagement surface 189

(134) 187a corner of inner hexagonal tool engagement surface 189

(135) 189 inner hexagon tool engagement surface

(136) k distance

(137) L disengagement direction

(138) 191 main force transferring portions of the tool operating surface 193

(139) 191a main force transmitting portion of the tool operating surface 193

(140) 193 tool operating surface

(141) 195 portions of the tool engagement surface 189

(142) F fixation direction

(143) 197 protrusion

(144) l length of weak spot 183

(145) m length of adjacent portion of tool operating surface 189

(146) 199 point

(147) 200 bolt

(148) 201 drive

(149) 203, 205, 207 weak spots

(150) 209, 209a protrusions

(151) r, s lengths

(152) 220 bolt

(153) 221 drive

(154) 223a, 223b weak spots, recesses

(155) 225a, 225b weak spots, recesses

(156) 227a, 227b protrusions

(157) 229 tool

(158) 231 tool operating surface

(159) S mirror plane