KEYLESS STEERING LOCK

Abstract: The lock includes a locking and unlocking bar (18) engageable with a steering shaft (10). A hanger member (19) is movable in unison with the bar (18) and a spring (20) urges the hanger member (19) and the bar (18) together towards a locking position in engagement with the shaft (10). A rotator (21) is kept in cooperating contact with the hanger member (19) and is rotatable between a first and a second posrtion corresponding to the locking position and the unlocking position of the bar (18). The rotator (21) is formed with a sector cam (29) which has a rounded apex (30) adapted for establishing sliding contact with the hanger member (19) during the shaft-locking operation and an arc (33) adapted for establishing sliding contact with the hanger member (19) during the shaft-unlocking operation. Further, the sector cam (29) has a sector angle (α), measured at the apex (30) thereof from 15 to 150°, most preferably about 90 degrees.

Description: STEERING LOCK This invention relates to a steering lock, and more specifically to an improvement in or relating to a keyless steering lock wherein a shaft-locking and unlocking bar is operated from an electric motor through a reduction gear and a rotator. Conventionally, steering locks have been designed as mechanical locks which are key-operated for locking and unlocking. More recently, however, keyless steering locks have been developed in which the operator actuates a plurality of specifically selected switches, e.g. buttons, In sequence so as to automatically unlock the lock and render the steering shaft operable as desired by the operator. In such an arrangement, a locking and unlocking bar is driven by an electric motor by way of gearing and a rotator, the latter having a cam portion of some sort for actuation of the bar in the desired sense, that is to say either in the shaft-locking or -unlocking direction, as the case may be. According to our experience, however, it is extremely difficult to control precisely rotation of the rotator, so as to exactly position the latter at the desired shaft-locking or unlocking pos: tion, on account of Likely over-running of the motor or frictional resistance of co-operatlng parts. This in turn often leads to excess or insutYiclent advancement or the locking bar ana thus to the possibility of malfunction of the lock. In the field of control engineering, stepping motors are widely usea for suppression of such dieadvantageous over-running or premature stopping. Such stepping motors are, however, much too large and much too expensive commercially for use in keyless steering locks. It is, thererore, an object of the present invention to provide an improved steering lock which can operate in a highly precise manner without excess or insufficient advancement of the shart-locking and unlocking bar. This object is achieve in accoraance with the present invention by provision or an improvea steering lock comprisinga locking ana unlocking bar engageaule with a steering shaft, a hanger member movable in unison with the bar, spring means urging the hanger member ana the bar together towaras a locking position in engagement with the shart, and a rotator which is hela in co-operating contact with the hanger member and is rotatable between a first ana a secona position corresponaing to the locking position ana the unloc#ing position of the bar, characteriseu in that the rotator is rormeu wlth a sector cam which has a rounded apex adaptea for establishing sliaing contact with the hanger member during the shaftlocking operation and an arc adapted for establishing sliding contact with the hanger memDer auring the shart-unlocking operation. Advantageously, the sector angle measured at the apex or the sector cam is from 15 to 1#0 degrees, most preferably about yo degrees, The invention will be described further, oy way of example, with reference to the accompanying arawlngs, in which: Fig. 1 is a sectional elevation of a preferred emoodiment of the steering lock or the invention; Fig. 2 is a top plan view of the steering loct shown in Fig. 1, the lici or cover having Deen omitted for more clear illustration of the inside arrangement; Fig. 3 is an enlargeu sectional view or the Dearing arrangement for the steering shaft in the steering loct shown in Fig. 1; Fig. 4 is a slightly enlargeu section taken along the section line A - A' shown in Fig. 2; and Fig. 5 is an end view or the rotator carrying the sector can in the steering locz shown in Figs. 1 to 4. In the arawings, which illustrate a preferred emuoaiment of the steering lock or the invention, a conventional steering shaft 10 is rotatable supported Dy a oall @earing unit 12 positively supportea in a lock housing 13. This housing 13 is formed with a hollow cylindrical portion 14 in which the nearing unit 12 is mounted, for example, Dy a pressure or push-in fit. In the upper part or the housing li, a guide opening 17 is arranged in communication with the hollow cyllndrlcal space 14 ana container chambers 15. The upper parr or the housing 13 is tigntly ana rigidly closes Dy a lid 1# which is a removable snap- fit or pressure fit therein for the purpose of theft-prevent ion. A locking oar 18 is sliaably mountea in the guile opening 17, the bar 18 being shown in Fig. 1 at its advanced and locking position in engagement with a reception recess 11 formed on the steering shaft 10. A no-oalled "hanger-member" 19 is attached to the locking bar 18 and slides in unison therewith. The hanger member 19 may be directly fixed to the bar 18. A comprossion coil spring 20 is mounted Detween lid 16 and hanger member 19 under compression and thus urges the bar 1# to move downwards in Fig. 1. A member 21 called a rotator" is held in pressure contaot with the hanger member 19, as is clearly shown inFig. 5 in side view, This rotator 21 acts to prevent excess or i > gufficient advances ment of the bar 18, as will be des@ribed more fully later. An electric motor 22, a gearing unit 23 and an output shaft 36 thereof are mounted in the housing 13 as shown. Rotation is transmitted from the motor 22 through the gearing unit 23 ti) the output rirhaft 3t. The gearing unit 23 is housed in a casing 24 which is shown in cross-section in Fig. 4. In the casing 24 two diametrically opposite openings 27 and 2# are provided for housing respeotive contactless lead switches 34 and 3 > . The former switch 34 is adapted for sensing the shaft-unlocking position of the bar 1#, while the latter switch 35 senses the shaft-looking position of the bar 18. then the motor 22 is energized to rotate, output torque is transmitted therefrom through the reduction gearing 23, the output shaft 36, a mechanical coupling 2000 provided between the latter and the rotator 21 to the hanger member 19 and thence to the locking bar 18, so as to raise the latter from its locking position shown in Fig. 1 towards its mlocting upper position, As shown in rig. 5, the rotator 21 is formed with a sector cam 29, having a cam angle alpha between side slopes 31 and 32, measured around an apex 30, of substantially 15 to 150 degrees, most preferably about 90 degrees. In the shaft-looking position, the switch 35 is positioned nearest to a shaft-position indicator magnet in or on the rotator 21 so as to energize that switch. At the same time, the other switch 34 is remote from the same magnet 2#, so that switch 34 is de-energized. When a certain switch (not shown) is turned on, the motor 22 is rotated and motion is transmitted therefrom through the reduction gearing 23, the output shaft 36 and the coupling 200 to the rotator 21. Motion is further transmitted from the cam 2Y of the rotator 21 to the hanger member 19 which is fixedly attached to the locking bar 1 so as to raise the latter, as indicated in Fig. 1, towards its unlocking position. As the bar 15 moves towards its unlocking posit ion, the magnet 2v is brought towards its position adjacent to the switch 34 which senses the unlocking position and de-energizes the motor 22 by causing opening of the on-off switch (not shown) for the latter. In this way, precise locking and unlocking operations can be assured, the shape of the sector cam 29 being of particular importance in this respect. In place of the aforementioned lead switches 34, 35, microawitches may be used if desired. It will be clear from the foregoing detailed description that with the improved steering shaftlock according to the present invention which incorporates a rotator provided with a specifically designed sector cam an accurate shaft-locking and unlocking operation can be assured, even if the motor should make an over-running or the rotator should stop at inaccurate shaft-locking or unlocking positions.

Claims: CIJAIMS: 1. A steering lock comprising a locking and unlocking bar (18) engageable with a steering shaft (iso), a hanger member (19) movable in uniaon with the bar (15), spring means (20) urging the said hanger member (19) and the bar (18) together towards a locking position in engagement with the shaft, and a rotator (21) which is held in co-operating contact with the hanger member (19) and is rotatable between a first and a second position corresponding to the locking position and the unlocking position of the bar (18), charac tensed in that the rotator (21) is formed with a sector cam (2#) which has a rounder apex (30) adapted for establishing sliding contact with the hanger member (19) during the shaft-locking operation and an arc (33) adapted for establishing sliding contact with the hanger member (19) during the shaft-unlocking operation. 2. A steering lock as claimed in Claim 1 wherein the sector cam (29) has a sector angle (;(), measured at the apex 30 thereof, of from 15 to 1500, most preferably about 90 degrees.

Inventors: NARA, ETUO
Applicants: KOKUSAN KINZOKU KOGYO KABUSHIKI KAISHA
Application year: 1984
Main classification: B60R25
IPC codes: B60R25