Patent Publication Number: US-6902191-B2

Title: Tilt setting device for a steering column

Description:
FIELD OF THE INVENTION 
     The present invention relates to a tilt setting device for a steering column of a vehicle. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     A steering column generally includes a main column, a tilt head, and a pivot joint, such as a universal joint, which pivotably connects the tilt head to the main column. A steering wheel is mounted on the tilt head. The pivot joint rotatably fixes the tilt head to the main column to allow the rotation of the steering wheel to be transmitted from the tilt head to the main column. However, the pivot joint allows the tilt head to pivot relative to the main column so that the driver can adjust the tilt angle in accordance with his preference. 
     The steering column also includes a tilt setting device which the driver can use to adjust the tilt angle of the tilt head and to set the tilt head at a desired tilt angle. The tilt setting device may have an elongated configuration with two ends. One end of the tilt setting device is connected to the main column, and the other end is connected to the tilt head. The length of the tilt setting device may be adjusted to adjust the tilt angle of the tilt head. 
     The tilt setting device may include a sleeve and a rod which is disposed telescopically in the hollow center of the sleeve. Each of the sleeve and rod has first and second ends. The second end of the rod extends into the hollow center of the sleeve from the first end side of the sleeve. The first end of the rod is preferably coupled pivotably to one of the main column and tilt head, and the second end of the sleeve is preferably coupled pivotably to the other of the main column and tilt head. Preferably, the rod is pivotably coupled to the one of the main column or tilt head with a pin that extends through a hole on the rod. Similarly, the sleeve may be pivotably coupled to the other of the main column or tilt head with a pin that extends through a hole on the sleeve. The pins may be fixed to the respective main column and tilt head. The length of the tilt setting device may be defined as the distance between the first end of the rod and the second end of the sleeve. 
     The length of the tilt setting device may be adjusted by sliding the rod relative to the sleeve telescopically, i.e., in the longitudinal direction. The length of the tilt setting device may be set by securing the rod to the sleeve in the longitudinal direction to prevent relative longitudinal movement between the sleeve and the rod. 
     To secure the rod to the sleeve, the hollow center of the sleeve may have an inner surface that has length-wise opposite surfaces and width-wise opposite surfaces, wherein the length-wise surfaces may be spaced farther apart than the width-wise surfaces. Preferably, the width-wise opposite surfaces are threaded, and the length-wise opposite surfaces are unthreaded. Additionally, the outer surface of the rod may also have length-wise opposite surfaces and width-wise opposite surfaces, wherein the length-wise opposite surfaces are threaded, and the width-wise opposite surfaces are unthreaded. 
     Preferably, the hollow center of the sleeve and the rod are dimensioned so that when the threaded width-wise surfaces of the sleeve&#39;s hollow center face the threaded length-wise surfaces of the rod, the inner threads of the hollow center engage the outer threads of the rod to prevent the rod from sliding relative to the sleeve telescopically. On the other hand, when the threaded width-wise surfaces of the sleeve&#39;s hollow center face the unthreaded width-wise surfaces of the rod, the inner threads of the hollow center disengage the outer threads of the rod to allow the rod to slide relative to the sleeve telescopically. 
     With this arrangement, the locking and unlocking of the rod with the sleeve can be accomplished by rotating the sleeve relative to the rod or by rotating the rod relative to the sleeve. When the rod and sleeve are pivotably coupled to the respective main column and tilt head, in order for the rod or sleeve to rotate, the hole on the rod or sleeve, through which the pin extends to pivotably couple the rod or sleeve to the respective main column or tilt head, may have an elongated configuration and may extend laterally, i.e. may extend in a direction perpendicular to the longitudinal direction of the rod and sleeve. As the rod or sleeve rotates, the pin slides in the laterally extending, elongated hole. 
     Normally, the rod is locked with the sleeve to set the tilt head at a desired angle, and the pin is located at a first end of the elongated hole. In order to unlock the rod with the sleeve to adjust the tilt angle, the rod or sleeve is rotated, and the pin moves from the first end of the elongated hole to the second end. In order to facilitate the movement of the pin from the first end of the elongated hole to the second end, the elongated hole may be tapered with the second end wider than the first end, i.e. at least one side of the elongated hole is tapered. 
     The tilt setting device may include a spring that biases the rod or sleeve towards the locked position with the pin located at the narrower end of the elongated hole. To reset the tilt angle, the rod or sleeve is rotated to the unlocked position against the spring torque with the pin moving from the narrower end of the elongated hole to the wider end. After the tilt angle has been reset, the rod or sleeve is released to allow it to return to the locked position under the spring torque. 
     Applicant has recognized a problem associated with prior art tilt setting devices. The problem is that, when any force is applied to the tilt setting device in the longitudinal direction, the tapered side(s) of the elongated hole tends to push the pin towards the wider end of the elongated hole and to rotate the rod and sleeve in the unlocked direction. This may accidentally unlock the tilt setting device when the rod and sleeve are in the unlocked position. 
     In the present invention, to prevent this from happening, at least one of the sides of the elongated hole may be untapered near the narrower end of the elongated hole. The untapered region may be generally defined as a region that does not have an increased width in the direction of the wider end of the elongated hole. Preferably, the untapered region is a flat region. When the pin is at the narrower end of the elongated hole, the pin is in, or rests against, the untapered region. Consequently, when the rod or sleeve is at the locked position (i.e. when the pin is at the narrower end of the elongated hole), longitudinal forces applied to the tilt setting device can no longer cause the pin to move towards the wider end of the elongated hole and cause the rod and sleeve to rotate in the unlocked direction. 
     As defined herein, the words “length-wise” and “width-wise” do not imply that the cross sections of the rod and sleeve&#39;s hollow center have a rectangular configuration or even an oblong configuration. In certain cases, they simply mean that the rod or sleeve&#39;s hollow center has two opposite surfaces (length-wise surfaces) that are farther apart that two other opposite surfaces (width-wise surfaces). For example, the sleeve and rod may each have an elliptical cross-section. The length-wise opposite surfaces may be the surfaces at the opposite ends of the major axis of the ellipse, and the width-wise opposite surfaces may be the surfaces at the opposite ends of the minor axis. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of a vehicle steering column. 
         FIG. 2  is a perspective view of a tilt setting device as installed in a steering column. 
         FIG. 3  shows that the inner threads of the sleeve&#39;s hollow center is disengaged with the outer threads of the rod to allow the rod to slide relative to the sleeve telescopically. 
         FIG. 4  shows that the inner threads of the sleeve&#39;s hollow center is engaged with the outer threads of the rod to prevent the rod from sliding relative to the sleeve telescopically. 
         FIG. 5  shows the elongated hole on the sleeve. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  illustrates a steering column  10  for a motor vehicle. The steering column  10  may include a main column  12 , a tilt head  14 , and a pivot joint  16 , which pivotably connects the tilt head  14  to the main column  12 . A steering wheel  18  is mounted on the tilt head  14 . The pivot joint  16  rotatably fixes the tilt head  14  to the main column  12  to allow the rotation of the steering wheel  18  to be transmitted from the tilt head  14  to the main column  12 . However, the pivot joint  16  allows the tilt head  14  to pivot relative to the main column  12 . 
     As shown in  FIG. 1 , the steering column  10  also includes a tilt setting device  20  which the driver can use to adjust the tilt angle of the tilt head  14  and to set the tilt head  14  at a desired tilt angle. The tilt setting device  20  may have an elongated configuration with two ends. In the illustrated embodiment, one end of the tilt setting device  20  is connected to the main column  12 , and the other end is connected to the tilt head  14 . The length of the tilt setting device  20  may be adjusted to adjust the tilt angle of the tilt head  14 . 
     As shown in  FIG. 2 , the tilt setting device  20  preferably includes a rod  22  pivotably coupled to the tilt head  14 , and a sleeve  24  pivotably coupled to the main column  12 . The rod  22  may be disposed telescopically in a hollow center  26  of the sleeve  24 . Preferably, the rod  22  is pivotably coupled to the tilt head  14  with a pin  28  that extends through a hole on the rod  22 . Similarly, the sleeve  24  may be pivotably coupled to the main column  12  with a pin  30  that extends through a hole  32  on the sleeve  24 . 
     The length of the tilt setting device  20  may be adjusted by sliding the rod  22  relative to the sleeve  24  telescopically. For securing the rod  22  to the sleeve  24  to set the length of the tilt setting device  20 , as shown in  FIG. 3 , the hollow center  26  of the sleeve  24  may have an inner surface  34  that has length-wise opposite surfaces  36  and width-wise opposite surfaces  38 , wherein the length-wise surfaces  36  may be spaced farther apart than the width-wise surfaces  38 . Preferably, as shown in  FIG. 3 , the width-wise opposite surfaces  38  of the sleeve&#39;s hollow center  26  are threaded, and the length-wise opposite surfaces  38  are unthreaded.  FIG. 3  also shows that the outer surface  40  of the rod  22  also has length-wise opposite surfaces  42  and width-wise opposite surfaces  44 , wherein the length-wise opposite surfaces  42  are threaded, and the width-wise opposite surfaces  44  are unthreaded. 
     Preferably, as shown in  FIG. 4 , the hollow center  26  of the sleeve  24  and the rod  22  are dimensioned so that when the threaded width-wise surfaces  38  of the sleeve&#39;s hollow center  26  face the threaded length-wise surfaces  42  of the rod  22 , the inner threads  46  of the hollow center  26  engage the outer threads  48  of the rod  22  to prevent the rod  22  from sliding relative to the sleeve  24  telescopically. On the other hand, when the threaded width-wise surfaces  38  of the sleeve&#39;s hollow center  26  face the unthreaded width-wise surfaces  44  of the rod  22 , as shown in  FIG. 3 , the inner threads  46  of the hollow center  26  disengage the outer threads  48  of the rod  22  to allow the rod  22  to slide relative to the sleeve  24  telescopically. 
     With this arrangement, the locking and unlocking of the rod  22  with the sleeve  24  can be accomplished by rotating the sleeve  24  relative to the rod  22 . When the sleeve  24  is pivotably coupled to the main column  12 , in order for the sleeve  24  to rotate, the hole  32  on the sleeve  24  may have an elongated configuration, as shown in  FIG. 5 , and may extend laterally, i.e. may extend in a direction perpendicular to the longitudinal direction of the sleeve  24 . The elongated hole  32  allows the pin  30  to slide in it and the sleeve  24  to rotate. 
     The elongated hole  32  has a narrower end  50 , a wider end  52  and sides  54  extending between the narrower and wider ends  50 ,  52 . At least one of the sides  54  of the elongated hole  32  may be tapered and may include an untapered region  56 , preferably a flat region, adjacent the narrower end  50 . When the pin  30  is in the untapered region  56  at the narrower end  50  of the elongated hole  32 , the threads  48  of the rod  22  are engaged with the threads  46  of the sleeve&#39;s hollow center  26  to prevent relative longitudinal movement between the sleeve  24  and the rod  22 . When the pin  30  is at the wider end  52  of the elongated hole  32 , the threads  48  of the rod  22  are disengaged with the threads  46  of the sleeve&#39;s hollow center  26  to allow relative longitudinal movement between the sleeve  24  and the rod  22 . In order to unlock the rod  22  from the sleeve  24  to adjust the tilt angle, the sleeve  24  is rotated, and the pin  30  moves from the narrower end  50  of the elongated hole  32  to the wider end  52 . 
     The tilt setting device  20  may include a spring  56  that biases the sleeve  24  towards the locked position with the pin  32  located in the untapered region  56  at the narrower end  50  of the elongated hole  32 . To reset the tilt angle, the sleeve  24  is rotated to the unlocked position against the spring torque with the pin  32  moving from the narrower end  50  of the elongated hole  32  to the wider end  52 . After the tilt angle has been reset, the sleeve  24  is released to allow it to return to the locked position under the spring torque. 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.