Tilt-lock device for tilt-type steering column

Abstract: A clamp is fixed to a robust portion of a vehicle body. The clamp is formed with spaced first side walls which define therebetween a recess for passing therethrough a jacket tube of a steering column. A distance bracket is formed with spaced second side walls which support thereon the jacket tube. The distance bracket is slidably movably disposed between the first side walls of the clamp in such a manner that outer surfaces of the second side walls are in contact with inner surfaces of the first side walls. Opening are formed in lower portions of the first and second side walls. A fastening bolt passes through the openings and has a threaded leading end projected outside of one of the first side walls. The fastening bolt is suppressed from rotation about its axis relative to the first side walls. A nut is operatively engaged with the threaded leading end of the fastening bolt. The nut forces the first side walls to incline toward each other when turned about the threaded leading end in a fastening direction. There is employed a means for lowering a possibility of producing a gap between each of the first side walls and each of the second side walls when the fist side walls are forced to incline toward each other.

Description: The present invention relates in general to a lock device for a tilt-type steering column in accordance with the generic clause of claim 1. More specifically, the present invention is concerned with a tilt-lock device by which the tilt-type steering column can be tightly and adjustably fixed to the vehicle body at a desired angle. US-A-5,338,064 which shows the features of the preamble of claim 1 discloses such a tilt-lock steering column of a motor vehicle, comprising: a clamp adapted to be fixed to a body of said motor vehicle, said clamp being formed with spaced first side walls which define therebetween a recess for passing therethrough a jacket tube of the steering column; a distance bracket formed with spaced second side walls which support thereon said jacket tube, said distance bracket being slidably movably disposed between the first side walls of said clamp in such a manner that outer surfaces of said second side walls are in contact with inner surfaces of said first side walls; openings formed in lower portions of said first and second side walls; a fastening bolt passing through said openings and having a threaded leading end projected outside of one of said first side walls, said fastening bolt being suppressed from rotation about its axis relative to said first side walls; a nut operatively engaged with said threaded leading end of the fastening bolt, said nut forcing said first side walls to incline toward each other when turned about said threaded leading end in a fastening direction. Hitherto, various lock devices for tilt-type steering columns have been proposed and put into practical use in the field of wheeled motor vehicles. With such lock devices, the tilt-type steering column can be fixed to the vehicle body at a desired angle to allow a driver to have an ideal driving posture. In order to clarify the task of the present invention, one known lock device for the tilt-type steering column will be briefly described with reference to Figs. 5 and 6 of the accompanying drawings, which is shown in Japanese Patent First Provisional Publication 6-286621. For ease of description, such lock device will be referred to as "tilt-lock device" in the following. The tilt-type steering column shown in Figs. 5 and 6 is of a lower-pivot type which has a lower portion pivotally connected to a lower part of a vehicle body and an upper portion detachably and adjustably fixed to the vehicle body through the tilt-lock device. That is, as is seen from these drawings, the tilt-lock device comprises an upper clamp 3 which is secured to a robust structure of the vehicle body under a dashboard or the like. The upper clamp 3 is formed with two side walls 3a and 3b between which a generally rectangular recess 3c is defined. The rectangular recess 3c extends generally vertically. The side walls 3a and 3b are spaced from each other by the distance "A". Vertically slidably held by the upper clamp 3 is a distance bracket 5 which has side walls 5a and 5b intimately slidably engaged with inside surfaces of the side walls 3a and 3b of the upper clamp 3. For this sliding connection, the distance "B" between the side walls 5a and 5b of the distance bracket 5 is determined substantially the same as the distance "A". The side walls 5a and 5b are formed with inwardly bent support portions 5a' and 5b' for supporting and holding a jacket tube 2 of the steering column. As is seen from Fig. 6, the side walls 3a and 3b of the upper clamp 3 are formed with aligned elongate openings 6a and 6b (only 6a is shown) each extending vertically, while, as is seen from Figs. 5 and 6 the side walls 5a and 5b of the distance bracket 5 are formed with aligned circular openings 7a and 7b each having a diameter substantially equal to the width of the elongate openings 6a and 6b. As is seen from Fig. 6, a tightening bolt 8 passes through the elongate and circular openings 6a, 6b, 7a and 7b which are aligned. Although not shown in the drawing, a nut is secured to the left side wall 3a (when viewed in the drawing) of the upper clamp 3, with which a threaded left end of the tightening bolt 8 is operatively engaged. Thus, when the tightening bolt 8 is turned about its axis in a fastening direction, the side walls 3a and 3b of the upper clamp 3 are forced to bend toward each other thereby to grip the distance bracket 5 therebetween tightly. With this, the jacket tube 2 of the steering column is tightly held by the tilt-lock device. While, when the tightening bolt 8 is turned in an unfastening direction, the tight engagement between the distance bracket 5 and the upper bracket 3 becomes cancelled. Under this condition, the distance bracket 5 can be easily moved or pivoted up or down together with the jacket tube 2 by a degree determined by the length of the elongate openings 6a and 6b. That is, the steering column can be shifted or pivoted to a new angular position. Thereafter, the tightening bolt 8 is turned in the fastening direction. With this, the steering column is fastened to the vehicle body at the new angular position. However, due to its inherent construction, the above-mentioned known tilt-lock device has the following drawbacks. That is, as is seen from Fig. 6, when the tightening bolt 8 is turned in the fastening direction, the side walls 3a and 3b of the upper clamp 3 are forced to incline toward each other. However, such inclination of the side walls 3a and 3b tends to produce a wedge shaped gap "S" between each side wall 3a or 3b of the upper clamp 3 and the associated side wall 5a or 5b of the distance bracket 5. As is seen from the drawing, production of such gap "S" causes insufficient coupling between the upper clamp 3 and the distance bracket 5. In other words, as shown in the drawing, due to production of such gap "S", the practical distance "H" between the upper clamp 3 and the distance bracket 5 becomes large because actually these two parts are connected to each other at their mutually contacting portions which are pressed against each other by the tightening bolt 8, which induces a poor grasping of the jacket tube 2. In fact, such insufficient coupling brings about a higher possibility of transmitting undesired engine vibration to a steering wheel (not shown) mounted on the steering column, which gives the driver an unpleasant feeling. Furthermore, such insufficient coupling tends to produce noises particularly when the tilt-lock device is used for a long time. It is therefore an object of the present invention to provide a tilt-lock device for a tilt-type steering column, which is free of the above-mentioned drawbacks. This object is met by the features of claim 1. Preferred embodiments are shown in the subclaims. Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a side view of a tilt-type steering column to which a tilt-lock device of an embodiment of the present invention is practically applied; Fig. 2 is an enlarged sectional view taken along the line II-II of Fig. 1; Fig. 3 is a sectional view of a distance bracket employed in the tilt-lock device of the first embodiment; Fig. 4 is a right-half sectional view of the tilt-lock device of the first embodiment, showing an ideal coupling between the distance bracket and an upper clamp; Fig. 5 is a partially sectional exploded view of a known tilt-lock device for a tilt-type steering column; and Fig. 6 is a right-half sectional view of the known tilt-lock device in an assembled condition Referring to Figs. 1 to 4, there is shown a tilt-lock device 100A which is a embodiment of the present invention. As is best seen from Fig. 1, the tilt-lock device 100A is applied to a tilt-type steering column 1 which generally comprises a jacket tube 2 and a steering shaft 13. The steering shaft 13 passes through the jacket tube 2 and includes a lower projected end 13a connected through a universal joint 50 to a steering mechanism 52 of a motor vehicle and an upper projected end 13b having a steering wheel (not shown) connected thereto. A lower portion of the jacket tube 2 is movably held by a lower clamp 4 fixed to the vehicle body. A middle portion of the jacket tube 2 is adjustably held by the tilt-lock device 100A of the invention in such a manner as will be described in the following. As is seen from Figs. 1 and 2, the tilt-lock device 100A comprises an upper clamp 3 which is secured to a robust structure of the vehicle body. Slidably movably held by the upper clamp 3 is a distance bracket 5 which holds the jacket tube 2 of the steering column. Similar to the above-mentioned known tilt-lock device, the upper clamp 3 is formed with two side walls 3a and 3b between which a generally rectangular recess 3c is defined. The rectangular recess 3c extends generally vertically. As is seen from Fig. 2, vertically slidably held between the two side walls 3a and 3b of the upper clamp 3 is the distance bracket 5. The distance bracket 5 has side walls 5a and 5b intimately slidably engaged with inner surfaces of the side walls 3a and 3b of the upper clamp 3. The side walls 5a and 5b of the distance bracket 5 are formed with inwardly bent support portions 5a' and 5b' for supporting and holding the middle portion of the jacket tube 2 of the steering column. If desired, the support portions 5a' and 5b' may be welded to the jacket tube 2. The side walls 3a and 3b of the upper lamp 3 are formed with aligned elongate openings 6a and 6b each extending vertically, while, the side walls 5a and 5b of the distance bracket 5 are formed with aligned circular openings 7a and 7b each having a diameter substantially equal to the width of the elongate openings 6a and 6b. A tightening bolt 8 passes through in order the elongate opening 6a, the circular opening 7a, the other circular opening 7b and the other elongate opening 6b, which are aligned. As shown in Fig. 2, the tightening bolt 8 includes a projected right end 8a which constitutes an enlarged head and a projected left end 8b which has a nut 10 operatively engaged therewith. Between the bolt head 8a and the right side wall 3a of the upper clamp 3 and between the nut 10 and the left side wall 3b of the upper clamp 3, there are disposed washers 11a and 11b respectively. It is to be noted that the fastening bolt 8 has a non-cylindrical part 8c slidably engaged with opposed side walls of the elongate opening 6a of the right side wall 3a of the upper clamp 3. With this engagement, the fastening bolt 8 is suppressed from rotation about an axis thereof. A lock lever 9 is fixed to the nut 10 to rotate therewith. Thus, when the lock lever 9 is manipulated to turn the fastening bolt 8 in a fastening direction, the side walls 3a and 3b of the upper clamp 3 are forced to bend toward each other thereby to grip the distance bracket 5 therebetween. According to the present invention, the following unique measures is employed. That is, as is seen from Figs. 3 and 4, when the distance bracket 5 is kept dismantled from the upper clamp 3, that is, when the distance bracket 5 is kept applied with no stress, the distance "C" between upper ends of the side walls 5a and 5b is substantially equal to the distance between inner surfaces of the side walls 3a and 3b of the upper clamp 3 and greater than the distance "B" between lower ends of the side walls 5a and 5b. That is, the distance bracket 5 is so produced or pressed as to establish the following inequality: C > B Thus, as is understood from Figs. 2 and 4, when, due to manipulation of the lock lever 9 in the fastening direction, the side walls 3a and 3b of the upper clamp 3 are inclined toward each other, the inner surface of each side wall 3a or 3b of the upper clamp 3 can entirely contact with the outside surface of the associated side wall 5a or 5b of the distance bracket 5 without producing or leaving the above-mentioned undesired wedge shaped gap "S" therebetween. That is, as is seen from Fig. 4, the practical distance "H" between the upper clamp 3 and the distance bracket 5 becomes very small, because each side wall 3a or 3b of the upper clamp 3 and the corresponding side wall 5a or 5b of the distance bracket 5 are entirely and evenly pressed against each other by the tightening bolt 8. Thus, a tight coupling is established between the upper clamp 3 and the distance bracket 5 unlike the case of the above-mentioned known tilt-lock device of Fig. 8. Thus, the undesired engine vibration transmission to the steering wheel and the production of noises are suppressed or at least minimized. Of course, when the lock lever 9 is turned in an unfastening direction, the tight coupling between the upper clamp 3 and the distance bracket 5 becomes cancelled and thus the steering column can be easily moved or pivoted to a new angular position. Thereafter, the lock lever 9 is turned in the fastening direction to lock the steering column at the new angular position. As will be understood from the foregoing description, in the embodiment 100A of the present invention, the distance bracket 5 is so produced that the distance "C" between the upper ends of the side walls 5a and 5b thereof is substantially equal to the distance between the side walls 3a and 3b of the upper bracket 3 and greater than the distance "B" between the lower ends of the side walls 5a and 5b. With such measures, the practical distance "H" between the upper clamp 3 and the distance bracket 5 or 12 becomes small, as has been mentioned hereinabove. Thus, tight coupling between the upper clamp 3 and the distance bracket 5 or 12 is established upon turning of the lock lever 9 in the fastening direction, as has been described hereinabove.

Claims: A tilt-lock device for a tilt-type steering column of a motor vehicle comprising: a clamp (3) adapted to be fixed to a body of said motor vehicle, said clamp being formed with spaced first side walls (3a,b) which define therebetween a recess (3c) for passing therethrough a jacket tube (2) of the steering column; a distance bracket (5) formed with spaced second side walls (5a,b) which support thereon said jacket tube (2), said distance bracket being slidably movably disposed between the first side walls (3a,b) of said clamp (3) in such a manner that outer surfaces of said second side walls (5a,b) are in contact with inner surfaces of said first side walls (3a,b); openings (6a,b;7a,b) formed in lower portions of said first and second side walls; a fastening bolt (8) passing through said openings (6a,b;7a,b) and having a threaded leading end projected outside of one of said first side walls (3a,b) said fastening bolt (8) being suppressed from rotation about its axis relative to said first side walls; a nut (10) operatively engaged with said threaded leading end of the fastening bolt (8), said nut (10) forcing said first side walls (3a,b) to incline toward each other when turned about said threaded leading end in a fastening direction, characterized in that said distance bracket (5) has such a structure that when said distance bracket (5) is applied with substantially no stress, the distance (C) between upper ends of said second side walls is substantially equal to the distance between said first side walls (3a,b) and greater than the distance (B) between lower ends of said second side walls (5a,b) to lower the possibility of producing a gap between each of said first side walls (3a,b) and each of said second side walls (5a,b) when said fist side walls (3a,b) are forced to incline toward each other. A tilt-lock device as claimed in Claim 1, in which the second side walls (5a,b) of said distance bracket (5) are respectively formed with inwardly bent support portions (5a',b') for supporting and holding said jacket tube (2). A tilt-lock device as claimed in Claim 2, in which said inwardly bent support portions (5a',b') are welded to said jacket tube (2). A tilt-lock device as claimed in Claim 1, further comprising a lock lever (9) which is secured to said nut to rotate therewith. A tilt-lock device as claimed in Claim 4, further comprising: a washer (11a,b) operatively disposed between a head portion (8a) of said fastening bolt (8) and the other of said first side walls, said head portion (8a) being projected outside of the other of said first side walls (3a,b); and another washer (11a,b) operatively disposed between said nut (10) and said one of said first side walls (3a,b).

Inventors: KURITA HARUHIDE, KURITA, HARUHIDE, Kurita, Haruhide, c/o FUJI KIKO CO., LTD.
Applicants: FUJI KIKO KK, FUJI KIKO COMPANY LIMITED
Application year: 1999
Main classification: B62D1
IPC codes: B62D1