ADJUSTABLE HANDLEBAR STEM FOR A BICYCLE OR SIMILAR VEHICLE

Abstract: Adjustable and lockable handlebar stem comprising a post (1) to be clamped in the forward frame tube of a bicycle, one upper (2) and one lower (3) profile arm pivotably supported in bearing points (6, 7) on said post (1), and a handlebar piece (4) with a through hole (5) for accommodating a handlebar (15), said handlebar piece (4) also being pivotably supported by said two profile arms (2, 3) in bearing points (8, 9). The profile arms (2, 3) can be locked together, for example by means of a stud (10) in a slide groove, and due to the unequal distances between said bearing points (6, 7) resp. (8, 9) there is achieved an ergonometrically favourable rotation of the handlebar (15) itself when the position of the complete mechanically movable unit (2, 3, 4) is changed.

Description: ADJUSTABLE HANDLEBAR STEM FOR A BICYCLE OR SIMILAR VEHICLE The present invention relates to an adjustable handlebar stem for bicycles, raopeds, motorcycles and furthermore all steerable devices which utilize a corresponding steering principle as a bicycle. More specifically, the invention relates to a simultaneous handlebar height and forward/backward position joint adjustment means which can be locked. Until to-day, the bicycle has usually been equipped with a handlebar stem which only has the possibility for a straight up and down adjustment. However, special adjustable handlebar stem devices of various types are previously known, which are adapted for various purposes. Recently however, some handlebar stem manufacturers have in addition made it possible to vary the length of the handlebar stem protrusion. The result is that the handlebar may be placed in almost any position. When the position of the handlebar is to be varied, the handlebar itself must also be rotated in order that the brake handles shall fall into the hands in a natural and ergonometrically correct manner. In order to adjust the handlebar with the previously known handlebar stem device, one must consequently first loosen three bolts, thereafter move the handlebar into the desired position, and then refasten the same three bolts. The three bolts have the following respective purposes: a) adjusting the bicycle handlebar up and down, b) adjusting the protrusion in a direction toward or away from the bicyclist, and c) rotating the handlebar itself around the handlebar main axis. From Belgian patent no. 523 314 is previously known a device having certain qualities in common with the present invention, namely an adjustable device using two parallel arms which can be locked in a stepless manner by means of a wing nut in one of the bearing points in order to provide a handlebar adjustment substantially in height. The handlebar travel is from an upper extreme position, downward and forward, and thereafter further downward and backward again to a lower extreme position. Because of the parallellogram guiding the handlebar maintains its orientation in a vertical plane, i.e. its rotational orientation around the handlebar main axis, through the whole movement. For quite some time the possibility of varying the body posture during cycling has been missed, in other words, there has been a want for a simple and practical device on the bicycle for providing such a possibility. In the first place it is uncomfortable to sit bicycling in the same position for a long time. Secondly, by varying the sitting posture on the bicycle, a more effective bicycling is achieved. When bicycling uphill, or possibly when bicycling at a higher speed on the flat, it is often found more efficient when the handlebar is in a low and relatively far advanced position. However, when bicycling in dense traffic, where a good view is necessary, it is often found most appropriate to sit in a rela¬ tively high and upright posture. With a handlebar stem in accordance with the present invention, a lockable adjustment of the handlebar position is achieved in a simple manner, possibly while riding, and without the use of tools, and particularly ergonometrically correct and consequently wholesome and comfortable variation possibilities for the bicyclist's sitting posture are achieved. The purpose stated above is obtained by putting into use a handlebar stem of the type which is defined precisely in the enclosed patent claims. In a preferred embodiment of the adjustable handlebar stem in accordance with the invention, a possibility of varying the handlebar position is achieved along a curve over and in front of the bicycle frame. The curve runs from a position up and close to the bicyclist, to a position which is down and further away from the bicyclist. In accordance with the invention the adjustable handlebar stem is moved by merely loosening one single clamping device. After changing the handlebar position, the handlebar is clamped in a new position by relocking the clamping device. During movement of the handlebar from one position to another, the adjustable handlebar stem in accordanc with the invention will provide rotation of the handlebar by itself. The invention shall now be illuminated more closely by referring to a non-limiting embodiment example, and also referring to the drawings, where fig. 1 shows a sketch of an embodiment of a handlebar stem in accordance with the invention, in a side view, fig. 2 shows the travel of the movable parts in the handlebar stem in fig. 1, fig. 3 shows the handlebar stem in two positions on a bicycle, fig. 4 shows a perspective view of the handlebar stem, fig. 5 shows an embodiment of a handlebar stem in accordan with the invention, comprising a locking means for fixed positions, in a side view, and fig. 6 shows an example of an embodiment with a springing device. In fig. 1 is illustrated an example of a handlebar stem in accordance with the invention, in a side view. In the preferre embodiment the handlebar itself will be located in front of the handlebar stem post 1, which post shall be entered down into the forward bicycle frame tube 14 (see fig. 3) and clamped. The handlebar 15 (see fig. 4) is clamped in the hole 5 in a handlebar piece 4 in a per se well known manner, however this i only shown in fig. 4. An upper profile arm 2 and a lower profile 3 are pivotably supported in both ends in bearing points 6, 7, 8 and 9, and thus it is possible to move the profile arms 2 , 2 around the bearing points 6 and 7, in two directions until outer positions are reached where the geometry or the materialwise construction prevents further movement. The complete movable mechanism thus consists of four parts, where post 1 is in a fixed position when mounted on the bicycle. The two profile arms 2, 3 are both pivotably supported in both the handlebar piece and the post, so that they can rotate in dependence of each other around their two respective axis pairs. In the shown embodiment, a stud 10 on a protruding part 13 on the upper profile arm 2 provides, in combination with a groo 11 in the lower profile arm 3 , a locking means in such a manner that the two profile arms 2 and 3 can be locked together in selectable positions between and out to the two outer positions, the upper outer position being shown in fig. 2. Furthermore it appears that the mechanism of fig. 2 can be moved a small distance further down/forward before reaching the lower outer position. The particular feature of the handlebar stem in accordance with the invention is that the distance a between the two bearing points 6 and 7, as appears from fig. 1, is unequal to the corresponding distance b between bearing points 8 and 9 on the handlebar piece 4, and in the preferred embodiment shown here, a is larger than b. This fact ensures that when rotating from an upper position for the movable parts down to a lower position, the handlebar 15, being clamped in the hole 5, will rotate in the opposite rotation direction. This fact provides the correct ergonometric conditions when considering hand gripping ordinary brake handles fixedly mounted on the handlebar 15. In the upright position, see fig. 2, it is natural with a brake handle pointing in a slanted downward direction in connection with an upright body posture, but when it is desired to lower the handlebar in a forward direction and take a more efficient bicycling posture, the elbows are lowered at the same time, and the brake handle grip will naturally be more horizon¬ tally inclined. The movement of the handlebar stem in accordan with the present invention provides exactly such an effect. In fig. 2 this rotation effect is tentatively displayed in a clear manner by showing (a purely illustrative) indicator line 16, which in the drawing rotates in a clockwise direction when the handlebar is lowered in an anti-clockwise movement from above and down toward the left. By providing an appropriate design of the profile arms 2 and 3, a simple and effective locking method is also achieved. For example, profile arm 3 is equipped with a groove 11, and stud 10 on the protruding part 13 on profile arm 2 gives a possibility for providing a locking means which in the shown embodiment is able to clamp the protruding part 13 solidly to the lower profile arm 3 in any of the possible positions. Providing such simple and effective locking or clamping means which also may be operated while riding, is of course possible by means of ordinarily known techniques. One example of such a per se known locking device, well known from bicycle racing, is a wheel hub quick-clamp mechanism, and such a clampi device is both simple in use and sufficiently strong. It is also possible to operate the locking means from a handle on the handlebar 15 itself. Furthermore, it is possible to use other different types of locking means for clamping the two profile arms 2 and 3 solidly against each other, apart from the example shown in the drawings and providing a possibility for locking in any position between the outer positions. The profile arms may be constructed with different design types, and the bearing points 6, 7, 8 and 9 can be located in different manners in relation to each other, so that various suitable travel curves 12 (see fig. 2) for the handlebar 15 are achieved. By locating the bearing points appropriately, the swing of the handlebar movement as well as the rotation of the handlebar during movement may be varied. As previously mentioned, the variations are achieved by moving the bearing points when constructing the stem, or by increasing their mutual spacings. Thus, the most suitable and favourable type of constructio is achieved by making the upper bearing point distance c (see fig. 1) shorter than the corresponding lower bearing points distance d. Hereby is achieved that the movement of the profile arms or possibly the handlebar piece 4 takes part substantially on the overside of a horizontal plane passing through pivot support point 7. Since due to an ergonometric consideration it is unfortuna that the handlebar moves backwards again when moving downward, bearing point spacings as well as remaining material design are preferably chosen in such a manner that the lower outer position of the profile arms movement at the same time consti¬ tutes a maximum forward protruding position of the handlebar. Furthermore, it should be noted that the four part construction described here, in the preferred embodiment has the particular feature that profile arms 2 and 3 are pivotably supported directly on the handlebar piece 4 , so that the movable mechanism constituted by handlebar piece 4, profile arms 2 and 3 and post 1, is an integrated and strong unit, in contrast to the previously known solution of the most closely related type, which in the known parallellogram guiding system displays separate clamps gripping around additional posts at each end. Thus, a construction like the one presented in the present invention, entails large advantages also when considerin construction strength. As previously mentioned, it is possible to use various types of locking mechanism. In fig. 5 is shown a possibility with fixed locking positions. Here the lower profile arm 3 is equipped with recesses 17 in its top surface. The recesses 17 have a substantially truncated wedge- or conical shape, and from the bottom of each recess 17 a thin hole 18 is drilled right down to the underside of profile arm 3 for leading a pulling wire 19 with an end ball 20 therethrough for an eventual change of wire. In the upper profile arm 2 there is formed an internal, downward directed bore 21, in which a slideable plunger 22 is located. Said plunger 22 has in its lower end 23 a shape which is complementary in relation to the recess shape, so that the lower end 23 can enter one of the recesses 17 with a tight fit. A strong spiral spring 24 placed in the bore 21 also pushes the plunger 22 downward into solid engagement with the recess 17. In order to hoist the plunger 22 for a change of position, there is arranged in the lower conical or wedge-shaped end 23 an aperture 25 aligned with hole 18, and with the same diameter, and aperture 25 is narrowing some distance up inside plunger end 23, in such a manner that a shoulder area is formed for engagement by the wire end ball 20, and the continuation of the aperture in the up direction has such a diameter that only the cable 19 itself can pass through it. Said wire 19 continues in an up direction centrally in plunger 22 and bore 21, and further through a nipple 26 on the top side of the upper profile arm 2 and further as a central wire in a Bowden cable. By pulling a not shown handle in the other end of said Bowden cable, plunger 22 can thus be hoisted out and up from the recess 17 in question, against the force from spring 24. When plunger 22 has been hoisted clear from the top side of lower profile arm 3 , the bicyclist may move the handlebar 15 (fig. 4) rapidly into one of the other fixed positions, plunger 22 sliding on the top side of lower arm 3 and striking down into the closest recess 17 in accordance with the motion, if the Bowden cable is released prior to having reached the desired position. As shown in fig. 5, the handlebar stem post 1 may suitably be equipped with a hole 27 for leading the front wheel brake wire therethrough. In order to achieve the further effect that the handlebar stem provides a favourable spring action, which may be of special interest when bicycling on a very rough (road) surface, the lower profile arm 3 in the last mentioned embodiment with fixed locking positions may be equipped with a part 28 or 29 of elastic material, for example hard rubber, see fig. 6. In fig. 6 only lower profile arm 3 is shown in an embodimen with three recesses 17. One possibility is that a smaller (hatched) part 28 around the recesses is made of hard rubber. Fixing screws are shown at 30, the whole inner central section 29 (inside a strong outer metal frame) of lower profile arm 3 being removable. The fact is that when using an elastic materia 28, a certain degree of wear must be counted on, so that the central section 29 must be changed after having been used for some time. Possibly the whole central section 29 (inside a strong outer metal frame) may consist of hard rubber, and it may be removable in the same manner as mentioned above. Suitably the plunger 22 should also be removable in a simple manner from the top side of upper profile arm 2 , the whole bore section for example being removable from the top side by screwing, and the possibility of removing the recess part in lower arm 3 in connection with the resilient embodiment may also be utilized for a non-resilient embodiment, i.e. a central part of lower profile arm 3 which comprises the recesses 17, may generally be arranged in a removable manner.

Claims: AMENDED CLAIMS [received by the International Bureau on 21 February 1990 (21.02.90); original claims 1 and 9 amended; other claims unchanged (3 pages)] 1. Adjustable handlebar stem for a bicycle or similar vehicle, said handlebar stem comprising a post (1) adapted to be entered and clamped inside the forward frame tube (14) of the bicycle, said post (1) substantially at the top and a pre¬ determined distance a thereunder being equipped with two first bearings (6, 7) with parallel bearing axes which are horizonta when the bicycle is standing in a normal position, said bearings (6, 7) pivotably supporting two profile arms, one upper (2) and one lower (3) , said profile arms (2, 3) in their distal ends in relation to said post (1) also being in a pivotable support relation to a handlebar piece (4) by means o upper (8) and lower (9) second bearings with axes which are parallel to said bearing axes of said first bearings (6, 7) , said handlebar piece (4) being equipped with a horizontal hole (5) for admitting and clamping the bicycle handlebar (15) , parallel to said bearing axes, said handlebar stem further comprising a locking means for arresting and locking the movable system which comprises said profile arms (2, 3) and said handlebar piece (4) , in a position between, or equal to one of, two extreme positions for the travel of said system (2 3, 4), c h a r a c t e r i z e d in that the distance b between the two second bearings (8, 9) is unequal to the distance a between the two first bearings (6, 7) , whereby the rotational orientation of said handlebar piece (4) , and consequently said handlebar (15) , about the axis of said hole (5) are variable when moving said system (2, 3, 4) between sai two extreme positions. 2. Handlebar stem as claimed in claim 1, c h a r a c t e r i z e d in that distance b is smaller than distance a, said two second bearings (8, 9) being located in front of said two first bearings when viewed in the riding direction. 3. Handlebar stem as claimed in claim 2, c h a r a c t e r i z e d in that upper bearing distance c between the upper one (6) of said two first bearings and said upper second bearing (8) , is shorter than lower bearing distance d between the lower one (7) of said two first bearings and said lower second bearing (9) , whereby it is achieved that the movement of said profile arms (2, 3) , eventually said handlebar piece 4, takes part substantially on the overside of a horizonta plane passing through the lower one (7) of said two first bearings. 4. Handlebar stem as claimed in claim 1, 2 or 3 , c h a r a c t e r i z e d in that one of said two profile arms (2, 3) is equipped with a groove (11) for sliding guide cooperation with a stud (10) on a protruding part (13) on the other of said profile arms (3, 2), said stud (10) being lockabl in any position in said groove (11) , said protruding part (13) including said stud (10) being equipped with said locking means. 5. Handlebar stem as claimed in claim 4, c h a r a c t e r i z e d in that said locking means, said groove (11) , said stud (10) and said protruding part (13) are adapted for opening, adjusting and locking while riding, said locking means in combination with said stud (10) preferably being constituted by a quick-release clamping device. 6. Handlebar stem as claimed in claim 1, 2 or 3, c h a r a c t e r i z e d in that said lower profile arm (3) is equipped with a number, for example five, of substantially truncated wedge- or conically shaped recesses (17) on its top surface, adapted for engaging cooperation with a spring loaded plunger (22) in a bore (21) in the upper profile arm (2) , said plunger (22) having a lower end (23) shaped comple entarily to the shape of said recesses (17) and hoistable by means of a pull-wire (19) against the force from an internally arranged spring (24) in said plunger (22) and bore (21) , whereby said plunger (22) and said recesses (17) constitute said locking means and provide locking action in said number of fixed positions. 7. Handlebar stem as claimed in claim 6, c h a r a c t e r i z e d in that a part (28, 29) of said lower profile arm (3) which comprises said recesses (17) , is made of a relatively hard elastic material, for example hard rubber, for obtaining a somewhat springing action. 8. Handlebar stem as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that said locking means is adapted to be operated by means of a handle on said handleba (15). 9. Handlebar stem as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that geometry and/or material design is/are chosen in such a manner that a lower extreme position for the movement of said profile arms (2, 3) a the same time constitutes a maximum forward protruding position of said handlebar (15) . 10. Handlebar stem as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that said profile arms (2, 3) are pivotably supported directly onto said handlebar piece (4) , so that said handlebar piece (4) , profile arms (2, 3) and said post (1) constitute an integrated unit. STATEMENTUNDERARTICLE19 The amendment of Claim 1 consists mainly in moving the sec clause of the characterizing part in previous Claim 1 into the last part of the claim preamble. At the same time the subject matter in question has been somewhat reworded, introducing the phrase "the movable system" consisting of the two profile arms and the handlebar piece. "The outer positions" has been amended into "the extreme positions". The remaining clause in the characterizing part of the Claim has been amended in a corresponding manner. Also in Claim 9 "outer position" has been amended into "extreme position".

Inventors: HALS CATO, HALS, CATO
Applicants: HALS CATO, HALS, CATO
Application year: 1989
Main classification: B62K21
IPC codes: B62K21