Stick of variable length and relative locking device

Abstract: A stick of variable length, comprising at least one upper tubular element (2) provided with an end grip and at least one lower tubular element (3), the tubular elements (2, 3) being inserted one inside the other with the possibility of axial sliding, the upper tubular element (2) having a longitudinal slit (4), at its free end, to be able to clamp on the lower tubular element (3), preventing axial sliding. At the join between the tubular elements (2, 3) a locking device (10) is provided comprising a hollow cylindrical body (11) housing said tubular element (2) and having a longitudinal slit (13), delimited by opposite protrusions (14, 15) through which passes a pivot (16) to which a lever (32) with a cam (31) is connected to draw said projections (14, 15) together or apart, and thus clamp or loosen said cylindrical body (11) on the tube (2), in which said lever (32) is separate from said cam (31) and can make a free rotation with respect to it, without drawing it into rotation, in order to facilitate opening of the device, allowing initial raising of the lever (32) with minimum effort. The invention also concerns the locking device in itself.

Description: The present invention relates to a stick of adjustable variable length and a relative locking device. Although the invention can be applied to any type of stick for sports, medical, ecological and other uses, for simplicity's sake specific reference will be made herein to ski sticks. Various types of ski sticks are known whose length can be adjusted to adapt to the height of the user. Among the systems proposed, the most widely used is that of providing for telescopic sliding of two tubes one inside the other, and locking by means of a special clamp that is tightened on the outer tube. EP-A-641 578 describes such a clamp which is particularly advantageous in that it has a somewhat flattened profile and has no projecting parts when the clamp is in the closed position. This clamp substantially comprises a hollow cylindrical body, open on one side, where the cam end of a closing lever is hinged. Such a clamp, though being technically valid, has shown some drawbacks during the opening stage. In fact, since the control lever of this device acts as the clamp closing cam, at the end of the stroke it is pressed against the outer surface of the cylindrical body of the clamp and/or tube of the stick, so that a certain initial force must be exerted to lift this lever and cause the clamp to open. This operation is sometimes rather difficult to carry out, especially for weaker individuals, particularly in low temperature situations. The object of the invention is to improve the locking device according to the above mentioned patent EP-A-641 578, eliminating the drawbacks described above and allowing easy opening of the device, with minimum effort. Another object of the invention is to allow improved closure of the locking device. These objects are achieved, according to the invention, with the characteristics listed in the appended independent claims. Preferred embodiments of the invention are apparent from the dependent claims. Basically, according to the invention, the clamp operating cam is freed from the maneuvering lever, allowing a certain angular play between lever and cam. In this way, when the locking device is in the closing position, the lever can be raised without the slightest effort, causing it to move through the above mentioned angle, so that there is good grip for subsequent opening, also drawing the cam into rotation. Furthermore, the fact of having freed the cam from the maneuvering lever, makes it unnecessary to go past dead center to keep the lever in the closed position, as was the case with conventional devices. Lastly, the sides of the operating lever can be provided with two teeth which enter the corresponding seats provided in the body of the clamp, causing a click which indicates perfect closure of the device. Further characteristics of the invention will be clearer from the detailed description that follows, referring to a purely exemplary and therefore non-limiting embodiment, illustrated in the appended drawing, in which: Figure 1 is a plan view of a locking device according to the invention mounted on a ski stick and shown in the closed position; Figure 2 is similar view to that in Figure 1, rotated downward 90°; Figure 3 is a view of the locking device alone, seen from the opposite side to that in Figure 1 and shown in the open position; Figure 4 is longitudinal section taken along the line IV-IV in Figure 7; Figure 5 is an end view of the locking device in the open position, taken from the lefthand side of Figure 3; Figure 6 is a view like that in Figure 5 in the closed position; Figure 7 is a median cross section of the locking device in the closed position, taken for example along the plane VII-VII of Figure 2; Figure 8 is an end view like that in Figures 5 and 6, showing the maneuvering lever in three different positions; Figure 9 is a sectional exploded view of the lever and the relative cam; Figure 10 is a sectional view like that in Figure 9, with the lever and the cam in the assembled condition and in two different angular positions. With reference to these figures, and in particular to Figures 1 and 2, a partial view of a ski stick 1 is shown, comprising an upper tubular element 2, bearing at its distal end a grip (not shown) and a lower tubular element 3, ending in a point and a disk (not shown). The lower tubular element 3 has a slightly smaller diameter than the upper element 2, so that it can slide telescopically inside the latter (see Fig. 4). Furthermore, in the upper tubular element 2, coinciding with the end thereof proximal to the tubular element 3, a longitudinal slit 4 is provided, which allows its diameter to be narrowed following external pressure, and thus clamped on the tubular element 3, so that axial sliding is prevented. The locking device according to the invention, indicated as whole with reference numeral 10 is situated at the join between the two tubes 2 and 3. The device 10 comprises a hollow cylindrical body 11, which is disposed around the terminal section 9 of the tubular element 2 and has an inner annular ridge 12, against which the end of the tube 2 abuts (see in particular Figure 4). The hollow cylindrical body 11 has a longitudinal cut or slot 13, delimited by two opposite longitudinal projections 14, 15 in said body 11. Coaxial through holes able to house a pivot support 16 are provided in said projecting parts 14, 15 (see in particular Figure 7). The pivot support 16 is essentially composed of a screw 17, which screws into a nut 18, so as to be able to regulate the length of the pivot. The screw 17 has a head 19, which abuts on the outer side of the projection 15, whilst the nut 18 is housed completely in the corresponding hole 20 provided in the projection 14, which has a greater diameter than the hole 21 provided in the projection 15 for passage of the screw 17. At the end of the nut 18 a hole 22 is also provided, for connecting of the cam and the maneuvering lever of the device, as will be described better below. In fact, on the outer side of the projection 14 a cam surface 30 is provided, shaped in a slightly concave manner (see in particular Figure 5), so that when a force is applied against said surface 30, the projection 14 is pushed against the projection 15 through the elasticity of the material making up the body 11, normally plastic, thereby causing closure of the clamp and thus clamping of the tubes 2, 3 without any possibility of reciprocal sliding. Said closing or opening force on the cam surface 30 is exerted by means of a cam 31, operated by a lever 32, constituting a separate element from the cam 31. The lever 32 and the cam 31 are assembled together with each other and with said pivot support 16, by means of a pin 25, which is inserted in the aligned holes provided in said elements, involving the entire length of the device. The lever 32 has a curved course and such a shape as to enter a corresponding seat provided in the cylindrical body, fitting it perfectly without projecting from its outer profile. In particular, the lever 32 has a base portion 33 having the same width as the cylindrical body 11, and able to position itself, when closed, in a corresponding seat 34 provided in the body 11, by means of a reduction in the thickness of the corresponding section, along the whole length of the body. The remaining part 35 of the lever 32, up to the free end, has a smaller width than the length of the body 11, and seats in a corresponding rectangular seat 36 with a corresponding width, provided in the body 11 and delimited by respective opposite vertical walls 37, 38. The free end 39 of the lever 32 is bent slightly outward and is the only part projecting from the profile of the clamp, to facilitate gripping during opening, as will be better described below. Furthermore, near the end 39 of the lever 32 a pair of side teeth 40 are provided which engage in corresponding hollows 41 provided in said opposite side walls 37, 38 of the cylindrical body 11, causing a click of the lever during closing. The base portion 33 of the lever 32 is fork-shaped, so as to enclose between its prongs 44 the cam 31, which in turn has a central cavity 45, inside which is housed the nut 18 of the pivot support 16. As can be seen better from the sections in Figures 9 and 10, the shape and assembly of the cam 31 and the lever 32 are such as to allow the latter a certain free angle of rotation, about 30° (see Figure 8), in which the movement of the lever is not transferred to the cam. This is achieved by making a tooth-shaped profile 50 in the base of the lever 32, which seats in a corresponding seat 51, substantially V- shaped with a flattened base, provided in the cam 31 (Figure 9). The width of the seat 51 is greater than the thickness of the tooth 50, so that the latter can move inside the seat, coming to rest, at the end of the stroke, against the respective side walls 52, 53 thereof, following a rotation in one direction and the other of the lever 32, as shown in Figure 10 with solid and broken lines, respectively. Provision of this angular play between the lever 32 and the cam 31 offers the considerable advantage, when the lever is in the closed position, of being able to raise the lever sufficiently, without exerting the least force, from position A to position B shown with a broken line in Figure 8. In position B the lever can be gripped much more effectively to move it from the open position C, making the can 31 rotate, and thus opening the locking device. The angle of rotation between positions B and C is indicated as 95° in Figure 8. It is only specified that in the neutral stroke to pass from position A to position B during opening of the lever 32, it is necessary only to overcome the resistance of the coupling between the teeth 40 and the respective notches 41 which is obviously rather weak. Freeing the lever 32 from the cam 31 has made it possible to achieve a further advantage with respect to conventional systems in which the lever and the cam were made in a single body. In these known systems, in fact, during closure the cam had to pass dead center during closing in order to keep the lever in the closed position. With the system according to the invention, on the other hand, the lever 32 makes it possible to position the cam 31 in a position that corresponds exactly to dead center, thus avoiding a lessening, albeit small, of the closing pressure between the tubes 2, 3 which normally occurs if dead center is passed. Moreover, the locking device according to the invention makes it possible to adjust the closing pressure and/or to adapt to tubes of slightly different diameters, regulating the pre-closing force of the cylindrical body 11 by regulating engagement of the screw 17 in the nut 18. From what has been described the advantages of the arrangement proposed by the invention are apparent. However it is clear that the invention is not limited to the embodiment previously described and illustrated in the appended drawings, but is open to numerous changes to the details that are within the scope of an expert in the field. In particular, the ski stick can be divided into more than two tubular elements that can slide telescopically one inside the other, providing a locking device according to the invention to join adjacent tubular elements. According to a preferred embodiment, the ski stick comprises three tubular elements and two locking devices. It is also apparent that the invention protects the locking device in itself, applied to clamping of any two tubular telescopic elements, forming, for example, an orthopedic stick, a stick for window cleaning, or other.

Claims: A stick of variable length, comprising at least two tubular elements: an upper tubular element (2) ending in a grip, a lower tubular element (3), said tubular elements (2,3) being joined together telescopically and being able to slide one inside the other, wherein the upper element (2) can be clamped on the lower element (3) to prevent axial sliding, and at least one locking device (10) comprising a hollow cylindrical body (11), able to house the region of joining between said tubular elements (2, 3), and having a longitudinal slit (13) extending for its whole length and delimited by opposite projections (14, 15) of the body (11), through which passes a pivot support (16), to which is pivotally connected a lever (32) with a cam profile (31), able to exert a pushing action during closure which tends to bring said projections (14, 15) together, and thus to clamp said hollow cylindrical body (11) on the tubes (2 and 3), and exert an opposite action during opening, characterized in that said lever (32) is separate from said cam (31) and can rotate freely through a certain angle with respect to it, without drawing it into rotation, so that during opening the lever (32) can be raised from the profile of the body (11) with minimum effort, to be brought into a position that facilitates gripping by the user. An adjustable stick according to claim 1, characterized in that said lever (32) has at its base portion, a tooth-shaped profile (50) seating loosely in a cavity (51) in the cam (31), abutting against one or the other of the side walls (52, 53) of said cavity (51) through rotation in one direction or the other of the lever (32), thus causing a neutral stroke of the lever (32). An adjustable stick according to claim 1 or 2, characterized in that said angle of free rotation of the lever (32) with respect to the cam (31) is about 30°. An adjustable stick according to any one of the preceding claims, characterized in that said lever (32) seats in a corresponding seat (34, 36) of the body (11), so as not to project therefrom, reciprocal click hooking means (40, 41) being provided respectively on the lever (32) and in the body (11) to indicate that closure of the device has occurred. A stick of adjustable length according to claim 4, characterized in that said lever (32), in the closed position, places said cam (31) in a position corresponding exactly to dead center. A stick of adjustable length according to any one of the preceding claims, characterized in that said lever (32) has a fork-shaped base portion, which encloses between its prongs said cam (31) which has a central cavity (45) housing one end of said pivot support (16), the lever (32), the cam (31) and the pivot support (16) having aligned holes for fixing of the whole by means of a pin (25), extending the entire length of the hollow cylindrical body (11). A stick of adjustable length according to any one of the preceding claims, characterized in that said pivot support (16) is adjustable in length to regulate the clamping pressure of the locking device. A stick of adjustable length according to any one of the preceding claims, characterized in that said hollow cylindrical body (11) has, at one end, an inner annular ridge (12), forming a stopping surface for the end of said upper tubular element (2). A stick according to any one of the preceding claims, characterized in that it comprises at least one intermediate tubular element between said upper tubular element (2) and said lower tubular element (3), respective locking devices (10) being provided between said intermediate element and said upper (2) and lower (3) elements. A locking device for a cylindrical element (2,3), comprising hollow cylindrical body (11) suitable for housing said cylindrical element (2, 3) and having a longitudinal slit (13), delimited by opposite projections (14, 15) of said cylindrical body (11), said projections (14, 15) being passed through horizontally by a pivot support (16), at one end of which is pivotally connected a lever (32) with a cam (31), acting against a cam surface (30) provided on the outer wall of said projection (14) to draw the projections (14, 15) together or apart, and thus to clamp said hollow cylindrical body (11) on the cylindrical element (2, 3), or loosen said cylindrical body (11), characterized in that said lever (32) is a separate element from the cam (31) and can rotate freely with respect thereto through a predetermined angle, which causes a neutral stroke of the lever (32), during which said cam (31) is not drawn into rotation. A locking device according to claim 10, characterized in that said lever (32) has, at its base portion, a tooth-shaped profile (50) seating loosely in a seat (51) of said cam (31) so that following rotation of the lever (32) in one direction or the other, said tooth (50) abuts against one or the other of the side walls (52, 53) of said seat (51), causing a neutral stroke of about 30°. A locking device according to any one of claims 10 to 11, characterized in that said lever (32) seats in the closed position in a seat (34, 36) in said hollow cylindrical body (11), without projecting from the outer profile thereof, click means (40, 41) being provided for hooking of said lever (31) and said hollow cylindrical body (11) to indicate that closure of the lever has taken place.

Inventors: PRONZATI LORENZO, PRONZATI, LORENZO
Applicants: PRONZATI LORENZO, PRONZATI, LORENZO
Application year: 1997
Main classification: F16B7
IPC codes: F16B7, F16B2