Abstract:
A stem connecting the handlebars and steerable fork of a cycle has one tube attached to the handlebars and another tube attached to the steerable fork with the tubes capable of being rotated and locked with respect to one another. This arrangement allows for various configurations of the handlebars and fork including the typical riding configuration as well as an alternate configuration where the handlebars are ‘folded’ with respect to the fork. Change in configuration is accomplished without tools by way of a biased locking arrangement for the tubes.

Description:
BACKGROUND 
       [0001]    The stem of a cycle, e.g. a bicycle, connects the handlebar with the steerable front wheel through the fork; the fork holding the front wheel. The quill is the vertical portion of the stem. In many designs the quill and the stem are unitary. The stem and the quill are critical parts on a bicycle because all forces the rider&#39;s arms make while pedaling go through the stem and the quill to the frame, and if either of them breaks there is no way to hold the bicycle with the hands and the rider will consequently end up on the ground. Stems are often adjustable in different ways: Some or all of the height, the angle to a vertical plane, and the angle on a horizontal plane, may be adjustable in different combinations. 
         [0002]    The setting for the long axis of the handlebar when the bicycle is being ridden is perpendicular to the plane of the front wheel. However, at the time of storing or transporting a bike on an elevator or a train, that setting may become inconvenient. Although this angle is usually adjustable, it requires a tool and takes significant time to adjust to and from the riding setting. In addition, the parts for accomplishing this adjustment are not designed to be used very often, e.g. any time it is desired to turn the handlebars parallel to the plane of the front wheel for storage or travel. 
         [0003]    Foldable bicycles usually have foldable stems or quills while non-foldable bicycles typically come with handlebars that, at best, are only foldable with special tools and knowledge as well as substantial time and effort. Examples of patents disclosing foldable handlebars include U.S. Pat. Nos. 5,269,550; 5,419,573; 6,637,288 and 7,243,573. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention is a cycle stem having handlebars attached to a top thereof, a fork attached to a bottom thereof and an adjustable quill, the adjustable quill comprising: an inside tube having an inside tube axis and an inside tube disc, the inside tube disc having formed therein an aperture radially spaced from the inside tube axis; an outside tube having an outside tube axis and an outside tube disc, the outside tube disc having formed therein an aperture radially spaced from the outside tube axis; and a locking element selectively disposed in one of an unlocked position and a locked position, the unlocked position characterized in that the locking element is disposed in only one of the outside tube aperture or the inside tube aperture and the locked position characterized in that the locking element is disposed in both the outside tube aperture and the inside tube aperture. 
         [0005]    A biasing element may also be provided, exerting a force toward the locked position of the locking element. This force may be overcome with a button on one of either the inside tube or the outside tube, thus moving the unit toward the unlocked position of the locking element. 
         [0006]    The locking element may be in the form of locking pins, each locking pin disposed adjacent a spring urging the locking pin into the locked position. Pushing pins may also be provided, disposed in the other of the inside tube aperture or the outside tube aperture and arranged to exert a force on the locking pins to overcome the urging force and push the locking pins into the unlocked position. 
         [0007]    A preferred embodiment of the cycle stem includes a bearing element radially disposed between the outside tube and the inside tube. The bearing element may be any one of a low friction sleeve, a plurality of ball bearings or at least one needle bearing. 
         [0008]    The adjustable quill of the present invention may, alternatively, be described as a first tube attached to a handlebar of the cycle; a second tube attached to a wheel fork of the cycle; and locking means for selectively locking and unlocking the first tube and the second tube in rotational relationship with one another. The locking means may include a biasing element exerting a force toward a locked position of the locking element; and a button on one of either the inside tube or the outside tube, the button adapted to have an external force exerted thereon capable of overcoming a biasing force from the biasing element toward an unlocked position of the locking element. This locking means may also include a first tube disc having first tube disc apertures therein; a second tube disc having second tube disc apertures therein; and at least one locking element disposed, in an unlocked position, only in the first tube disc apertures and, in a locked position, in both the first and second tube disc apertures. 
         [0009]    In a preferred embodiment of the present invention, the locking element includes locking pins, each locking pin disposed adjacent a spring urging the locking pin into the locked position. The locking element may further have pushing pins disposed in the second tube aperture capable of exerting a force on the locking pins to overcome the spring urging force and push the locking pins into the unlocked position. In another preferred embodiment of the present invention, the locking element has locking tabs of complementary shape to first and second tube disc apertures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1   a  is a cross sectional plan view of a portion of the stem of the present invention; 
           [0011]      FIG. 1   b  is a cross sectional plan view of a portion of the stem of the present invention; 
           [0012]      FIG. 1   c  is a cross sectional plan view of  FIG. 1   a  taken along section line A-A; 
           [0013]      FIG. 1   d  is a cross sectional plan view of  FIG. 1   b  taken along section line B-B; 
           [0014]      FIGS. 2   a - 2   d  are the same views as  FIGS. 1   a - 1   d  but with needle bearing instead of low friction sleeve; 
           [0015]      FIGS. 3   a - 3   c  are cross section details of an alternate embodiment of the present invention; 
           [0016]      FIG. 4  is a cross sectional plan view of a preferred embodiment of the present invention; 
           [0017]      FIG. 5  is a cross sectional plan view of a preferred embodiment of the present invention; 
           [0018]      FIG. 6  is a cross sectional plan view of a preferred embodiment of the present invention; 
           [0019]      FIG. 7  is a cross sectional plan view of a preferred embodiment of the present invention; 
           [0020]      FIG. 8  is a cross sectional plan view of another preferred embodiment of the present invention; 
           [0021]      FIG. 9   a  is a cross sectional plan view of a different preferred embodiment of the present invention; 
           [0022]      FIG. 9   b  is a cross section detail of the different preferred embodiment in an unlocked arrangement; 
           [0023]      FIG. 9   c  is a cross section plan view of  FIG. 9   b  taken along section line C-C; 
           [0024]      FIG. 10  is a cross section plan view of several combined preferred and alternate embodiments of the present invention; 
           [0025]      FIG. 11  is an exploded perspective view of a cycle steering mechanism showing the context of the present invention; and 
           [0026]      FIG. 12  is a side plan view of a bicycle stem. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]      FIGS. 11 and 12  show the quill  102  of the present invention and its relationship to the handlebars  20 , stem  100  and fork  30  of a typical bicycle. Anchoring bolt  11  is also shown due to its importance in attaching the quill  102  to the fork  30 . 
         [0028]      FIG. 1   a  is a cross section of the quill  102  of one possible embodiment of the present invention, showing the quill  102  having an inside tube  1  locked with respect to an outside tube  2 . Because the inside tube  1  is attached to the fork  30  and the outside tube  2  is attached to the handlebar  20 , locking the inside tube  1  and the outside tube  2  with respect to one another locks the handlebar  20 , fork  30  and front wheel  32  in a particular arrangement. One advantageous arrangement of the handlebar  20  and fork  30  is where the handlebar  20  is perpendicular to the plane of the front wheel  32 . Another advantageous arrangement of the handlebar  20  and fork is where the handlebar  20  is parallel to the plane of the front wheel  32 , i.e. the handlebar  20  is ‘folded’. 
         [0029]      FIG. 1   b  shows a cross section of inside tube  1  unlocked from, i.e. rotatable with respect to, outside tube  2 . Inside tube  1  is rotatable with respect to outside tube  2  because lock pins  7  have been pushed into an ‘unlocked’ position, to be further discussed below. In the arrangement shown in  FIG. 1   b,  the handlebar  20  may be rotated while the fork  30  and, thus, the front wheel  32  are not rotated. This is how an arrangement of the handlebar  20  for riding is transformed from or to an arrangement for storage or other arrangement in which it is useful to have the handlebars  20  folded. 
         [0030]    Disposed at the top of inside tube  1  is quill disc  4 . Quill disc  4  comprises a group of holes  34  extending into the quill disc  4  parallel to the centerline  101 . Centerline  101  defines an axis of both the inside tube  1  and the outside tube  2  in addition to other structural elements of the present invention. Each hole  34  has a center located a distance “R” from the centerline  101 . Stem disc  5  is disposed in or is part of outside tube  2 . Stem disc  5  also comprises a group of holes  36  extending into stem disc  5  parallel to the centerline  101  and centered a distance “R” from the centerline  101 . Disposed between inside tube  1  and outside tube  2  is a bearing element such as a low friction sleeve  3 . The low friction sleeve  3  may also be a ball bearing or a needle bearing. Low friction sleeve  3  keeps both tubes  1  and  2  in concentric alignment. Quill disc  4  and stem disc  5  are arranged such that holes  34  and  36  may be caused to line up by rotating inside tube  1  and outside tube  2  with respect to one another. Bushing  6  keeps this arrangement. In the embodiment of  FIG. 1  quill disc  4  is located below stem disc  5 . 
         [0031]    Each of inside tube  1 , outside tube  2 , bushing  6 , quill disc  4  and stem disc  5  have concentric through holes therein. A long anchoring bolt  11  extends through these holes and holds each of these elements together. Bolt  11  also anchors stem  100  to the fork  30  of the bicycle by anchoring nut  12 . 
         [0032]    Holes  34  and  36  are sized to receive lock pins  7 . Springs  8  at the bottom of either holes  34  or  36  and lock pins  7  are adjacent springs  8 . Each lock pin  7  is biased by spring  8  to extend a distance beyond the top of the hole in which the spring  8  to which it is attached is located. When holes  34  and  36  are in alignment, the portions of lock pins  7  extending beyond the tops of holes  34  may extend into aligned holes  36 . 
         [0033]    In  FIGS. 1   a  and  1   b,  holes  34  are shown having a lock pin  7  and adjacent spring  8 . In this arrangement, occupying holes  36  in the stem disc  4  are push pins  9  which push lock pins  7  and compress springs  8  when a particular push pin  9  is aligned with a particular lock pin  7  and button  10  is operated on by force “F”, shown in  FIG. 1   b.  Thus, if lock pin  7  is aligned with hole  36  then spring  8  will bias lock pin into hole  36 ; if no counteractive force is present, e.g. from push pin  9  as a result of force F, then lock pin  7  will be permitted to enter hole  36 . The length of lock pin  7  is chosen such that a portion thereof will always be disposed in hole  34 . Thus, if lock pin  7  enters hole  36  then it is no longer possible to rotate inside tube  1  with respect to outside tube  2 , i.e. the tubes are locked. When force F is exerted on button  10 , push pins  9  are caused to transmit this force to lock pins  7  thereby compressing springs  8 . Once springs  8  are compressed sufficiently that the tops of lock pins  7  exit completely holes  36 , inside tube  1  and outside tube  2  may be rotated with respect to one another. 
         [0034]    Thus, lock pins  7  entering holes  36  lock a particular arrangement of handlebar  20  and fork  30  and attached front wheel. It is possible to change this arrangement by applying force F on button  10 , which causes push pins  9  to force lock pins  7  out of holes  36 , and then turning outside tube  2  with respect to inside tube  1  until a desirable and available lockable arrangement of handlebar  20  and fork  30  is reached, at which point force F is released and springs  8  again force lock pins  7  into holes  36 , preventing relative rotation of tubes  1  and  2 . Springs  8  comprise the primary bias in the system. However, it is not necessary that springs  8  are the only source of bias. Among other places, more robust biasing elements  24  may contact the top face of quill disc  4  and bottom face of cup  14 , as shown in  FIG. 9 . 
         [0035]    A cup  14  on top of the button  10  prevents water from entering into the mechanism. 
         [0036]    When stem disc  5  has been rotated with respect to the quill disc  4  such that holes  34  are not aligned with holes  36  the button  10  can be released because the lock pins  7  cannot enter holes  36  and merely slide along the bottom face of stem disc  5 . Tubes  1  and  2  are unlocked and will rotate with respect to one another until lock pins  7  are again in alignment with holes  36 . If the number of holes  34 ,  36  in each disc  4 ,  5  is four and there is an equal angular distance between each successive hole, the mechanism may be locked every 90 degrees. 
         [0037]      FIG. 2  shows an alternative embodiment where low friction sleeve  3  has been replaced by needle bearings  13 , one adjacent the bottom of outside tube  2  and the other one adjacent the stem disc  5  and the bushing  6 . 
         [0038]      FIG. 3   a  is a detailed cross section showing the lock pins  7  extending into both discs  4  and  5 . Thus,  FIG. 3   a  shows a locked arrangement.  FIG. 3   b  shows the same cross section but the button  10  has been pressed down by force F, thus the push pins  9  have pushed down the lock pins  7  compressing the springs  8  and placing the lock pins  7  in the unlocked position ready to be rotate.  FIG. 3   c  shows the same cross section through outside tube  2  but with inside tube  1  rotated slightly; this is possible because tubes  1  and  2  are unlocked from one another. The springs  8  are still biasing the lock pins  7  but the tops of pins  7  abut the bottom surface of quill disc  4 , which provides the balancing force to the spring  8  bias. 
         [0039]      FIG. 4  is an alternative embodiment of the present invention wherein the stem is integral with the quill. Outside tube  2  has attached thereto or formed integrally therewith a stem body  15 . The stem body  15  includes a number of threaded holes  16  in which bolts  17  are screwed holding the stem  100  together. Adjustable extension  18  and handlebar holder  19  are part of the stem  100 . The handlebar  20  is firmly held between the adjustable extension  18  and the handle bar holder  19 . Handlebar  20  is removable and adjustable by means of bolts  17 .  FIG. 5  shows the same stem as  FIG. 4  in which an additional extension  21  has been placed in order to elongate the stem  100 , i.e. increase the distance between outside tube  2  and handlebar  20 .  FIG. 6  is the same as  FIG. 5  but with two additional extensions  21  instead of one, showing that is possible to add as many additional extensions  21  as necessary. 
         [0040]      FIG. 7  shows the stem with one additional extension  21  but in this case the stem  100  is pointing down. This is possible through rotation of the adjustable extension  18  by 180° and attachment of adjustable extension  18  against the stem body  15  using the same bolts  17  on the other set of threaded perforations  16 . 
         [0041]      FIG. 8   a  is another alternative embodiment of the invention. The quill disc  4  is above the stem disc  5 . This cross section shows the mechanism locked.  FIG. 8   b  shows button  10  pushed down, thus unlocking the mechanism and allowing inside tube  1  to rotate with respect to outside tube  2 . Quill disc  4 , stem disc  5 , lock pins  7 , push pins  9 , springs  8 , quill disc holes  34  and stem disc holes  36  operate in this alternative embodiment is the same way as described previously to lock inside tube  1  and outside tube  2 . 
         [0042]      FIG. 9   a  shows an alternative embodiment in accordance with the present invention. The locking tabs  40  are integral with or attached to button  10 . The locking tabs  40  shown in  FIG. 9  are keyed to quill disc slots  22 , and stem disc slots  23  formed in the peripheral edge of both the stem disc  5  and the quill disc  4 .  FIG. 9   a  is a cross section showing the locked configuration. Locking tabs  40  are keyed to and extend into both quill disc slots  22  and stem disc slots  23 , thus preventing relative rotation of inside tube  1  and outside tube  2 .  FIG. 9   b  is a detailed cross section showing the unlocked configuration. Pushing button  10  overcomes the force of biasing element  24 , e.g. a spring, and causes button  10  to move axially toward outside tube  2  until locking tabs  40  are no longer inside quill disc slots  22 . When locking tabs  40  are no longer inside quill disc slots  22 , inside tube  1  may be rotated with respect to outside tube  2 . Four slots in quill disc  4  and four slots in stem disc  5 , set 90° apart, affords four locking positions. As with the alternative embodiment of  FIG. 8 , the quill disc  4  and stem disc  5  may be inverted in the embodiment of  FIG. 9  and the locking tabs  40  may be associated with either the inside tube  1  and outside tube  2 .  FIG. 9   c  is a top section of the quill showing the four locking tabs  40  inside the four stem disc slots  23 . 
         [0043]      FIG. 10  is the same embodiment as  FIGS. 4 ,  5  and  6  with a locking mechanism like that of  FIG. 9 . The system is locked because locking tabs  40  are partially inside quill disc slots  22  and partially inside stem disc slots  23 . Stem disc  5  is part of stem body  15 . An extended biasing element  24  between the top face of the quill disc  4  and cup  14  keeps the button up and the mechanism locked. 
         [0044]    While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by one skilled in the art, from a reading of the disclosure, that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.