LOCKING MEANS FOR SAFETY BELTS

Abstract: Locking means for safety belts of the reel belt type intended for use preferably in vehicles, and provided with a strap webbing (3), which against bias of a spring can be unwound from a strap winding-up device. The same is comprising a strap reel rotatably journalled therein and a pawl mechanism (8), which is changeable between a position releasing the strap reel and a locking position, in which the strap reel is maintained locked against rotation in one direction. The strap winding-up device also comprises an activating means (7) for the change-over of the pawl mechanism to a locked position, when the activating means is subjected to an acceleration exceeding a predetermined value. The activating means exhibits a body (11) of inertia with a determined basal surface (14). The body of inertia can occupy a central rest position with a basal surface resting on a carrying surface (19), or a peripheric activated position, in which the body of inertia is tilted about a first pivoting centre (45). The activating means also exhibits a transmission element (12) which is provided to sense the positions of the body of inertia and to change-over the pawl mechanism (8). The activating means (7) exhibiting a second pivoting centre (44), about which the transmission element is arranged to pivot in connection with the change-over of the body (11) of inertia between the rest position and the activated position. The transmission element is provided with a shank (33), which in the rest position occupies a centric position relative to the axis of symmetry of the body of inertia. The same is provided to in a third pivoting centre (46) for the activating means (7) cooperate with its end with a guide surface (35) in the body of inertia in such a manner that the end of the shank is moved sideways by the body of inertia when the same is changed-over to its activated position.

Description: Title: Locking means for safety belts Technical field: S The present invention relates to a locking means for safety belts of the reel belt type intended for use preferably in vehicles, and provided with a strap webbing, which against bias of a spring can be unwound from a strap winding-up device comprising a strap reel rotatably journalled therein, a pawl mechanism, which is change- 0 . able between a position releasing the strap reel and a locking posi¬ tion, in which the strap reel is maintained locked against rotation in one direction, and an activating means for the. change-over of the pawl mechanism to a locked * position , when the activating means is subjected to an acceleration exceeding a predetermined value, and 5 comprising for one thing a body of inertia exhibiting a determined basal surface , which body can occupy a central rest position ' with the basal surface resting on a ca ding surface, or a peripheric ac- ~ tivated position , in which the body of inertia is tilted about a first pivoting centre, and for another thing a transmission element arran- 0 ged to be able to rest against a carrying surface and provided with a contact surface arranged to cooperate with the pawl mechanism and a sensor portion by cooperation with the body of inertia provided to sense its positions, the transmission element being arranged to rest against its carrying" surface, when the body of inertia is in its 5 rest position, in which the contact surface occupies a position, in which the pawl mechanism is free to occupy its releasing position, whereas the body of inertia is displaced from its rest position into the activated position, when said body of inertia is influenced by said acceleration exceeding" the predetermined value, and displaces 0 the transmission element thereby causing a displacement of the con¬ tact surface, the pawl mechanism being arranged to occupy its lock¬ ing position under the influence of the displacement of the contact surface. 5 Background: Locking means of the actual kind are intended to lock in depen¬ dence of an activating means actuated by forces of inertia a reel i OMPI with a strap webbing against the unwinding of said strap webbing wound onto said reel and to release the reel for the unwinding <?f said strap webbing respectively. Rigid claims are set forth as to the function of such activating means with respect to by way of ex- " ample reliability, sensitivity, quick response, resetting function etc. , ant it is- an object desired to provide an activating means , which to the utmost possible extent can be dimensioned to produce the best result. It is further an object desired that the necessary angle of inclination of the activating means relative to the horizontal plane is ' substantially as great for the resetting operation as for the activation of the actiavting means . This has not been possible to achieve in a satisfactory manner, which in the first place is .due to the great fric¬ tion between the different parts of the activating means . Owing to this the safety belt has been maintained in locked condition during an unfavourably long period of time after the activation, which has thus signified a hindrance for the user of the safety belt. It is therefore an object of the present invention to provide a locking means, in which the activating means can be designed in such a way that the friction forces can be kept small and substan- tially unchanged with respect to time. Hereby it is thus possible to provide the locking means with the best characteristics in order to fuHfill great demands on the function of the means . The solution: The said object is obtained by means of a locking means which is characterized by the combination of the activating means exhibiting a second pivoting centre, about which the transmission element- is arranged to pivot in connection with the chang"e-over of the body of inertia between the rest position and the activated position, a d of the sensor portion of the transmission element comprising a shank, which in the rest position occupies a centric position relative to the axis of symmetry of the body of inertia, said shank being provided at a third pivoting centre for the activating means to cooperate with a guide surface of the body of inertia in such a manner that the sensor portion of the transmission element is moved sideways by the body of inertia, when the body of inertia is changed over into acti¬ vated position . , O P Brief description of drawings : The invention will now be described in more detail by means of a few examples of embodiment, reference being made to the accompa¬ nying drawings, in which Figs . 1 and 2 show sections through a strap winding-up device forming part of a reel type safety belt, in which the locking means according to the invention can be applied to advantage, the Figs . 3 and 4 show a partly broken view of a locking device according to the invention for one thing in inactive and for another thing in activated * position, whereas Fig. 5 shows an exploded view of a part of the locking means according to the invention . Best mode of carrying out the i ention: A strap winding-up device of common type, in which the lock- ing means according to the invention can be applied to advantage, is shown schematically in Figs . 1 and 2. According to these figures the winding-up device substantially comprises a reel 2 to which the one end of the strap 3 of the safety belt is attached. The strap wheel is pivotably journalled in two end w r all elements 4, 5 and is intended to wind up and unwind respectively the strap of the belt under the actuation of a reel spring 6, w τ hich is enclosed in one of the end wall elements 4. An entirely schematically illustrated locking means is enclosed in the other end wall element 5 and substantially comprises an activating means 7 and a ratchet mechanism 8, which can be actuated by said activating means and is arranged to lock the strap reel against unwinding of the belt strap under certain con¬ ditions . The activating means according to the invention is an auto¬ matically functioning mechanism, which can be influenced by forces of inertia, and w ? hich is illustrated in more detail in the other figu- res . Also the ratchet mechanism 8 is shown in Fig. 2 in an entirely schematical view and in principle comprises a latching pawl 9, which is pivotably journalled about a part 16, and a ratchet tooth wheel 10. The latching pawl is intended to cooperate with the ratchet w τ heel 10 in order to lock it against rotation in one direction and alternati- vely to release the same, whereby the strap reel 2 is locked against rotation in one direction and released respectively. The above men¬ tioned mechanism is shown in Fig. 2 very . schematically for the sake gTTREΛ " ^ O PI WIPO of clearness , and it can in principle refer to a simple design, where the ratchet wheel 10 is fixedly secured to the strap reel 2. However, the pawl 9 must in such a design take up the load operating on the " belt strap, and the ratchet mechanism 8 is in practice so provided " that the illustrated -mechanism is arranged to initiate a second mecha¬ nism, which relieves the pawl 9 and* is intended to take up stresses in the belt strap . Such a mechanism can by way of example be arranged to. be initiated also by the forces of acceleration, which arise in connection with a rapid unwinding of the belt strap. How- * ever, more detailed description of such a mechanism has been omit¬ ted in. the present application, as it is not necessary for the under¬ standing of the function and principal design of the present inven¬ tion. As is best evident from Figs . 3 and 4 the activating means 7 is substantial^ composed of a body 11 of inertia and a transmission element 12. The body 11 of inertia has the form of a free, standing" pendulum and is made of a material of comparatively high density, by way of example of metal, as brass or similar. The body of inertia is enclosed in a space 13 with the form of a body of revolution in a housing 15, which exhibits an envelope surface 17 * on the outside shaped as a segment of a sphere. The body of inertia is provided with a foot 18 exhibiting a basal surface 14, by means of which it is arranged in a rest position (see Fig. 3) to rest against a lower carrying surface 19, which in its periphery blends into an annular conical lower guiding" edge 20. The body of inertia exhibits in its upper portion a conical envelope surface 21 on the outside, the angle of which is substantially adapted in such a manner that the body 11 of inertia in an activated tilting position (see Fig". 4) with its conical envelope wall 31 closely bears against the cylindrical envelope wall 22. The body 13 of inertia on its inside exhibits a cavity 23, w τ hich is divided up in two sections , viz. an upper section 24 of the form of an inverted frustrum of a cone and a lower section 26 of cylindri¬ cal form and thus exhibiting a cj'lindrical envelope wall 27. The transmission... element 12 exhibits a head 28, which in its upper portion covers the space 13 of the housing portion 15. The outer periphery of the head 28 of the transmission element exhibits OMH a downwards directed flange 29, by means of which the transmission element 28 rests against an annular upper carrying surface 30 and is in lateral direction guided by a ring-shaped guide edge 31. The head in its central portion exhibits an upwards facing convex contact surface 32, against which the pa v 9 is bearing. A sensor portion in the form of a shank 33 projects from the head in downwards direc¬ tion and extends into the cavity 23 through the section 24 and down into the cylindrical section 26. The shank 33 exhibits a cylindrical shape, its diameter substantially corresponding to the diameter of the cylindrical section 26, and its terminal end 34 is rounded off forming a convex portion the surface of which according to the illu¬ strated example exhibiting the form of a segment of a sphere. The transition to the rounded-off portion is according to Fig. 3 substan¬ tially in line with a tranistion portion 35 serving" the purpose of a guide surface and located between the • conical section 24 and the cylindrical section 26 of the cavity 23. The transition portion 35 ex¬ hibits a ring-shaped edge. The activation means 7 is secured to the end wall element 45 of the safety belt device by means of a holder 36 , which exhibits two through holes 37 for the introduction of fastening screw ? s or similar, by means of which the holder can be attached to the end wall ele¬ ment. The holder is shaped as a segment of a sphere cavity 38, of which the radius of curvature is adapted to the radius of curvature of the housing portion 15 of the activating means 7. Said housing portion 15 exhibits a laterally projecting" pin 39, which is intended to penetrate into a bore 40 of the sphere- segment shaped cavity 38 in the assembled condition of the device. This cavity moreover exhi¬ bits a projection 41 of a shape that corresponds to the shape of a recess 42 of the housing portion 15. Said housing portion 15 is kept in a predetermined position relative to the holder 36 due to the posi¬ tion of the pin 39 in the bore 40 and the position of the projection 41 in the recess 42. A correct control of the position of the activa¬ ting means 7 relative to the orientation of the vehicle is very essen¬ tial for the correct function of the means . Hov;ever, the reel device . 1 is mounted in different angles of inclination in different vehicles according to the location of the safety belt device etc. This variation with respect to the mounting of the reel device as a whole must be compensated by providing a correct collocation of the internal mecha¬ nism relative to the vehicle, so that the lower bearing surface 19 for the body 11 of inertia for example will be parallel to the basal plane of the vehicle. The correct collocation of the activating means " 7 can then be varied in a simple manner from design to design of the reel device by means of a change of position of the projection 41 and/or the bore 40 according to the intended mounting. By chang ing the position of the projection 41, so that it occupies different revolving positions round the bore, a desired revolving position of the housing part 50 can thus be obtained in different positions round a revolving axis extending through the bore 40. Also different direc¬ tions of this revolving axis can be obtained by changing the position of the bore 40. In each modification of the position of the activating device 7 in the holder 6 one must of course see to it that such a symmetry is obtained relative to the pawl 9 that a uniform activation is obtained for all imaginable tilting directions of the body 11 of in¬ ertia. The locking means according to the invention functions in the following manner. In connection with the movement of a vehicle pro- ' vided with the locking means according to the invention, the activa¬ ting means is in its rest position according to Fig. 3, w'hen the ve¬ hicle is at standstill or moves at an acceleration below τ a value pre¬ scribed by the traffic authorities . This goes for acceleration compo¬ nents in all directions, thus, also the laterally directed forces arising when turning a curve. A prerequisite condition for the activating means 7 to occupy a rest position makes it necessary that the vehicle is on plane ground or in case of an inclined ground surface that its angle of inclination is below a certain value. The locking means is then in its releasing" position, its pawl 9 not engaging the ratchet wheel 10, which is possible, because the body 11 of inertia with its foot 18 rests against its lower carrying" surface 19 , whereas the trans mission element 12 with its flange 29 rests against the upper carrying surface 30. When the activating means 7 is subjected to forces of accelera- tion in anyone lateral direction and exceeding a predetermined value, or when the vehicle is placed on an inclining foundation with an angle of inclination exceeding a certain value, the activating means is changed over to activated position according to Fig. 4. The body 11 of inertia then tilts about its lower annular edge 43 of its foot 18, as said edge gets support against the guide edge 20 at the car¬ rying surface 19. The transition between the lower bearing surface " 19 and the gude edge 20 forms the lower pivoting centre line along which the body 11 of inertia can tilt round anyone point depending upon in which direction it has been actuated . The inclination of the body 11 of inertia in the space 13 is limited by the cylindrical enve¬ lope wall 22, against which the body of inertia obtains a good sup- • porting contact with its conical envelope surface 21. In connection with a tilting" movement of the body 11 of inertia a laterally directed force operates agains the end 34 of the shank 33 of the transmission element 12. As the transmission element 12- at the same time is held with its flange 29 gripping around the guide edge 31 at the upper bearing surface 30 , the transmission element is lifted up b3 r a pivo¬ ting movement in opposite direction to the one of the body 11 of in¬ ertia, this pivoting movement taking place about a pivoting centre ' 44, which is located at the transition between the upper annular car¬ rying surface 30 and the ring-shaped guide edge 31. Thus , the pi- voting centre 44, is formed as points foUovring a circular line. Due to the conical shape of the section 24 of the cavity 23 the pivoting movement of the transmission unit can take place about its pivoting centre 44, which in the following is caUed the upper pivoting centre. An intermediate bearing area 46 is formed between the body 11 of inertia and the transmission element 12, said bearing area thus being a result of the articulated connection of the transmission element to the body of inertia. The bearing area 46 is substantially formed * by the area around the transition portion 35 between the cylindrical section 26 and the conical section 24. The end 34 of the shank 33 of the transmission element 12 in the area of transition to its rounded end pivots against said bearing area 46. As is evident when compa¬ ring the rest position of the activating device according to Fig. 3 with its activated position according to Fig. 4 only a quite insignifi¬ cant displacing movement in between surfaces bearing against each other takes place at the bearing area 46, a rolling movement of the transition portion of the transmission element 12 performed against the transition portion 35 between the cylindrical and the coni 1cal sec- O PI tion instead substantially taking place. The curved surface of the shank 33 at its end 34 permits the pivoting movement of the trans¬ mission element 12 in spite of the shank to some extent penetrating downwards into the cylindrical section 26 of the cavity 23. A slight " play is assured between the shank 33 and the envelope surface 27 of the C3 r lindrical section, so that any friction will not arise between the surfaces, which occupy a position opposite to the very bearing point 46, working at a certain activating occasion. When the transmission element 12 tilts up into the position illu- strated in Fig. 4, the contact surface 32 is raised, and then the pawl is pivoted upwards into a position in which, it engages the rat¬ chet wheel 10. In the device according to the invention it is thus essential that the friction in the bearing surfaces of the activation means is very low 7 , which is obtained at the lower and upper .pivoting centres 44, 45 respectively by a tilting of elements relative to each other without any displacing movement between surfaces bearing against each other taking place. A negligible friction arises at the interme¬ diate bearing area, and this is due to the insignificant displacing movement arising and the small contact surface present between the body 11 of inertia and the transmission element 12. Such a condition has been obtained by means of a carefully balanced location of the intermediate bearing area 46 relative to the pivoting centres 44, 45. It has turned out to be of advantage here that the intermediate bear n area 46 as little as possible deviates from a line connecting the upper and the lower pivoting centres 44, 45 * . A quick change-over of the activating means to its rest position is obtained by this low friction between the elements forming part of the activating means 7. As a matter of fact it is an object desired that the activating means does not retain the locking means in locked position , but instead that the strap reel is released as soon as the body 11 of inertia . is not actuated by forces of acceleration exceeding a certain value. This is generally expressed by a wording implicating that the angle of inclination relative to the horizontal plane, which the lower bearing surface 19 must exhibit before the body of inertia again occupies its rest position from its activated position, which angle is called the reset angel, shall as much as possible be equal to the corresponding angle required for tilting of the body 11 of O P inertia out of its rest position , which angle is called the tilting angle. The above of course relates to a situation, in which the activating means 7 is not subjected to any forces of acceleration . As soon as possible after the activating means 7 is no longer subjected to forces ' of acceleration exceeding a certain value or the foundation of the vehicle exhibits an inclination, which is smaller than a certain value, the body 11 of inertia is thus raised back again to its rest position according to Fig. 3. In this situation the same condition of forces are operating as when a transition takes place from the rest position to the activating position but they are now operating in opposite direction. Thus, the transmission element 12 is swung downwards about the upper pivoting centre 44, and at the same time the end 34 of the shank 33 is pivoted relative to the body 11 of inertia in the manner described above, until the rest position illustrated in Fig. 3 has been reached. Thus , as a consequence of the low friction at the bearing and pivoting points , the desired reset is very quick¬ ly obtained after the conditions of activation have ceased to exist. It has turned out that by means of the activating means according to the invention a re-set angle is obtained that only by one degree " deviates from the tilting angle of the activating " means " . " The invention is not limited to the embodiment described and shown above but can be changed within the scope of the accompany¬ ing claims . The body 11 of inertia a w?ell as the transmission element 12 can for example be of another shape. It can b} 7 " way of example be imagined that the transmission element 12 with the end of its shank 33 rests against a carrying surface., on which it performs its tilting movement. In this case it is necessary that guide edges later¬ ally control the lower end of the shank. The lower end can for ex¬ ample exhibit a plane surface, the bearing surface of the body of inertia also being plane. It is moreover not necessary-" .that the head 28 of the transmission element is completely closed, but can be bro¬ ken and exhibits the annular flange 29 and the contact part 32 and the connecting elements between the flange and the contact part and the shank 33. The cavity of the body of inertia does moreover not necessarily be of conical shape, as it can comprise a w τ ider for ex¬ ample cylindrical portion, in which case a supporting edge is obtained at the pivoting centre 46. Only one activating position has . for the -*&GREA» OMPI sake of clearness been treated. However, all the elements forming part of the activating means , and which are shown in Figs . 3 and 4, are forming bodies of revolution, and therefore several activating positions can occur in all imaginable lateral directions round an axis of symmetry through the body of inertia according to the appearing directions of force. O

Claims: Claims : 1. Locking means for safety belts of the reel belt type intended for use preferably in vehicles , and provided with a strap webbing" (3) , which against bias of a spring can be unwound from a strap ' winding-up device (1) comprising a strap reel (2) rotatably journalled therein, a pawl mechanism (8), W'hich is changeable between a posi¬ tion releasing the strap reel and a locking position, in w?hich the strap reel is maintained locked against rotation in one direction, and an activating means (7) for the change-over of the pawl mechanism to a locked position, when the activating means is subjected to an acceleration exceeding a predetermined value, and comprising for one thing a body (11) of inertia exhibiting a determined basal sur¬ face (14) , which body can occupy a central rest position with the basal surface resting on a carrying surface (19) , or a peripheric activated position, in which the body of inertia is tilted about a first pivoting centre (45) , and for another thing a transmission ele¬ ment (12) arranged to be able to rest against a carrying surface" (30) and provided writh a contact surface (22) arranged to cooperate with the pawl mechanism (8) and a sensor portion (33) by coopera- tion with the body of inertia' provided to sense its positions , the transmission element being arranged to rest against its carrying sur¬ face, when the body of inertia is in its rest position , in which the contact surface occupies a position in which the paw τ l mechanism is free to occupy its releasing position, whereas the body of inertia is displaced from its rest position into the activated position , when said body of inertia is influenced by said acceleration exceeding the pre¬ determined value, and displaces the transmission element thereby causing a displacement of the contact surface, the pawl mechanism being arranged to occupy its locking position under the influence of the displacement of the contact surface " , c h a r a c t e r i z e d b y, the combination of the activating means (7) exhibiting a second pivoting centre (44) , about which the transmission element is arran¬ ged to pivot in connection with the cange-over of the body (11) of inertia between the rest position and the activated position, an of the sensor portion (33) of the transmission element is formed of a shank (33) , which in the rest position occupies a centric position relative to the axis of symmetry of the body of inertia, said shank OMPI being provided at a third pivoting centre (46) for the activating means (7) to cooperate with a guide surface (35) of the body of in- ertia in such a manner that the sensor portion of the transmission' element is moved sideways by the body of inertia, wrhen the body of inertia is changed over into activated position. 2. Locking means according to claim 1, ch a r a c t e r ize d b y, the third pivoting centre (46) being substantially coinciding with the connecting line between, the first and the pivoting centre (44, 45). 3. Locking means according to claim 1 or 2, ch a ra c t eri z e b y, the body (11) of inertia exhibiting a cavity (23) with a cylindri cal section (26), into which the shank (33) with its free end (34) penetrates to some extent, and a section (24), which is widening as counted from the cylindrical section and for example exhibits conical form, the shank, the widened section and the cylindrical section oc¬ cupying such positions and being provided in such a manner relative to each other that the shank with its free end is in close contact with the envelope w^alls (25, 27) of the cavity and is permitted to pivot about the third pivoting centre. 4. Locking means according to claim 3, c h a r a c t e rize d b y, the free end (34) of the shank (33) exhibiting a convex surface 5.. Locking means according to claims 1 - 4, c ha ra c teri z e b y, the transmission element (12) exhibiting a head (28), on. which the contact surface occupies a centric location, and which head ex- hibits a peripherically located annular flange (29), by means of wrhich the transmission element (12) can rest on its carrying surface (30), which is annular and blends into a ring-shaped guide edge (31), which cooperates with the flange. 6. Locking means according to claim 5, c h a r a ct e rize d b y, the body (11) of inertia being enclosed by a housing part (15), which exhibits the shape of a sphere-segment and is detachably mounted in a holder (36), which exhibits a cavity (38) of the form of a hollow? sphere with the same radius of curvature as the housing part, said housing part exhibiting a pin (39) and a recess (42), while a bore (40) and a projection (41) provided in the cavity are adapted in such a manner that the housing part in mounted condition is fixed in a determined position relative to the holder. * f OM

Inventors: LINDBLAD S
Applicants: LINDBLAD S M, LINDBLAD S
Application year: 1980
Main classification: A62B35
IPC codes: B60R22, G01P15