FR2717539A1 - Blocking device for given position of tube sliding in another for regulating length of assembly such as camera tripod - Google Patents

Abstract

The device comprises a tube (3) is fixed externally at its end (30) has the smaller diameter tube (5) introduced into it. A hollow cylindrical piece (2) whose internal wall (20) is truncated on one part has its smallest diameter opening located on the side of the largest tube. The truncated part can be displaced longitudinally with the end part (40) of a collar (4) which is threaded on the smaller tube. The end part of the collar has a cylindrical internal part and truncated external part, and is transversely elastic. It covers internally an elastic sleeve (6) of external diameter corresponding to the internal diameter of the collar and of internal diameter slightly greater than the external diameter of the smaller diameter tube. The collar external truncated part is divided longitudinally into spaced strips (41).

Description

 The present invention relates to a locking device in a given position of a sliding tube in another.

 It is intended in particular to equip a walking aid device to allow a quick adjustment of the length, but it can also be intended for other uses, for example for adjusting the length of a foot, or tripod, a camera.

 It is known that a walking aid device must be adapted to the user's morphology, in particular to its size.

 Generally, these devices comprise two telescopic tubes, one of which is pierced at regular intervals, over a given length, of diametrical holes, and the other is provided with a locking system consisting of either a retractable pin or diametrical holes in which a screw or a pin is inserted after alignment with those diametrical holes of the first tube corresponding to the desired setting.

 This type of apparatus has the disadvantage that on the one hand the adjustment is only approximate, on the other hand the series of holes weakens the tube, and that finally the amplitude of adjustment is limited.

 Locking devices of a sliding tube are also known in another, in which the blocking is achieved by the expansion in the larger diameter tube of a cylindrical block made of elastic material integral with one end of the other tube, the deformation of said cylindrical block being obtained by compressing it in the longitudinal direction by tightening a screw passing through it longitudinally, the tightening, or loosening, of said screw being made by rotating the tubes relative to each other .

 However, if this device offers many advantages over previous devices, it has the disadvantage of not allowing a virtually instantaneous blocking to the desired length, and the quality and therefore the blocking efficiency is conditioned by the force used to operate the tightening of the two tubes, which can be a disadvantage for some users with a specific disability.

 The present invention aims to overcome these disadvantages by providing a locking device in a given position of a sliding tube in another, lighter and less expensive than existing ones, and allowing an almost instantaneous locking to the desired length.

 The blocking device according to the present invention is essentially characterized in that the larger diameter tube comprises, fastened externally to one of its ends, a hollow part of generally cylindrical shape whose inner wall is frustoconical on a part, its smaller diameter opening being located on the side of said tube; and in that said frustoconical portion can move longitudinally, in a limited manner, at least the end portion of a ring threaded onto the small diameter tube, said end portion of the ring being on the one hand cylindrical internally and externally frustoconical and, on the other hand, elastically transverse, and furthermore housing, internally, a sleeve of elastic material of external diameter corresponding to the internal diameter of said ring, and of inside diameter slightly larger than the outside diameter of the smaller diameter tube.

 According to another characteristic of the device according to the invention, the end of the hollow part located on the side of the smaller diameter tube is transversely flexible and comprises on its inner periphery at least one notch intended to cooperate with at least one corresponding notch practiced peripherally in the ring, a short distance from the frustoconical portion, for retaining the ring in the hollow part and / or maintain in position in said hollow part.

 According to a particular embodiment of the device according to the invention the smaller diameter tube comprises, at its end inserted into the other tube, a plastic plug, a part of which extends beyond the end of the tube, said part being elastic transversely and of a diameter slightly greater than the internal diameter of the larger diameter tube.

 The operation of the device according to the invention is as follows: the tube of smaller diameter, hereinafter referred to as "small tube", being introduced into the tube of larger diameter, hereinafter referred to as "large tube" , the movable ring containing the elastic sleeve is pulled manually on the opposite side to the large tube, the inner diameter of said sleeve being slightly greater than the outer diameter of the small tube, the latter can easily slide in the large tube. When the assembly is at the desired length, it exerts a manual thrust on the movable ring towards the large tube, which has the effect of moving the movable ring longitudinally in the hollow part, thereby the frustoconical elastic portion of the movable ring is crushed by the frustoconical inner wall of the hollow part, tightening the elastic sleeve on the small tube and blocking it.

 When a walking aid equipped with an assembly device according to the invention is used, the support on the large tube accentuates the pressure of the frustoconical inner wall of the hollow part on the elastic frustoconical portion of the movable ring, so on the elastic sleeve, which reinforces the blockage.

 The detent notches that comprise the hollow part and the movable ring advantageously prevent the accidental displacement of the movable ring relative to the hollow part, and thus prevent untimely release of the assembly.

 The plug which can be secured to the end of the small tube advantageously allows to slow down the sliding of the latter in the large tube, thus allowing a more precise adjustment of the length of the assembly, and also allowing the transverse immobilization of the tube. end of the small tube in the large position of use, this immobilization removing all the metal noise in use.

 The advantages and features of the present invention will emerge more clearly from the description which follows and which refers to the appended drawing, which represents several non-limiting embodiments thereof.

In the attached drawing:
- Figure 1 shows a longitudinal sectional view of an assembly device of two tubes according to the invention.

 - Figure 2 shows a perspective view and exploded of the same device.

 - Figure 3 shows a longitudinal sectional view of an element of the device according to the invention.

 - Figure 4 shows a half-sectional view of a second embodiment of a device according to the invention.

 With reference to FIGS. 1 and 2, it can be seen that a blocking device 1 according to the invention comprises, on the one hand, a hollow part 2 made of molded plastic, generally cylindrical, fixedly fastened externally to the end. 30 of a tube 3, on the other hand a ring 4, also of molded plastic material, able to be introduced partially into the hollow part 2 and to move longitudinally in a limited manner, and intended to be threaded on a tube 5 of outer diameter slightly smaller than the inner diameter of the tube 3.

 The movable ring 4 is divided into two parts, a part 40 intended to be introduced entirely into the hollow part 2 and consisting of several spaced longitudinal blades 41 giving it a certain transverse elasticity, and a part 42 of which only a portion 42 'is introduced. in the hollow room 2.

 The outer wall 43 of the portion 40 is frustoconical, its circumference decreasing towards its end, and its inner wall 44 is cylindrical, a recess 45 being made there to allow to accommodate a sleeve 6 of elastic material.

 The hollow part 2 has a frustoconical inner wall 20, the circumference of which decreases towards the tube 3.

 As can be seen more particularly in FIG. 1, in which the device 1 is represented in the pre-locking position, the end edge 21 of the hollow part 2 has a peripheral internal bulge 22 against which an external peripheral bead 46 abuts projecting. portion 42 'of the movable ring 4, preventing extraction of the movable ring 4 from the hollow part 2.

 This extraction can, however, be made in force by flaring the end edge 21 of the hollow part 2 which is cut longitudinally blades 23 in particular to allow assembly of the assembly.

 The blocking of the tube 5 in the tube 3 is achieved in the following way: when the tubes 3 and 5 are slidably adjusted to the desired length, the movable ring 4 is pushed back, keeping it by its part 42, in the hollow part 2, which has the effect of compressing the portion 40 against the inner wall 20 of the hollow part 2, and because of the transverse elasticity of the portion 40 the sleeve 6 is crushed on the tube 5, blocking thereof.

 An axial support on the tube 3 makes it possible to consolidate the blocking, in fact this support tends to introduce the mobile ring 4 more deeply into the hollow part 2.

 The release of the assembly is obtained by pulling the portion 42 of the movable ring 4 so that the portion 40 thereof and the sleeve 6 resume their original shapes.

 Referring now to FIG. 3, it can be seen that the tube 5 may comprise, fastened at its end 50 inserted in the tube 3, a plastic plug 7 designed to create a certain resistance to the displacement of the tube 5 in the tube 3, the plug 7 having for this purpose a portion 70 projecting beyond the end 50 of the tube 5 and made of several transversely elastic branches 71 which flare out so as to exert a pressure on the inner wall 31 of the tube 3.

 The plug 7 serves to keep the two tubes 3 and 5 assembled in a given position when there is no axial thrust from one to the other, to refine the length adjustment before blocking by means of the device 1.

 Referring now to FIG. 4, it can be seen that according to another embodiment, the end 21 of the hollow part 2 has on its inner periphery a notch 24, and that the portion 42 'of the movable ring 4 comprises externally a series of parallel peripheral notches 47.

 Thus, when the device 1 is in the locked position, that is to say when the movable ring 4 is pressed into the hollow part 2, the screen 24 snaps into the parallel notches 47, preventing any untimely release, the a snap-in operation being facilitated by the transverse elasticity of the end 21 of the hollow part 2 due to the blades 23.

 It goes without saying that the present invention can not be limited to the foregoing description of several of its embodiments, which may undergo a number of modifications without departing from the scope of the invention.

Claims (6)

1) Locking device in a given position of a sliding tube in another for a quick and easy adjustment of the length of the assembly, characterized in that the tube (3) of larger diameter comprises, secured externally at its end (30) into which is introduced the tube (5) of smaller diameter, a hollow part (2) of generally cylindrical shape whose inner wall (20) is frustoconical on a part, its smaller diameter opening being located on the side of said tube (3); and in that said frustoconical portion can move longitudinally, in a limited manner, at least the end portion (40) of a ring (4) threaded onto said small diameter tube (5), said end portion (40) of the ring (4) being on the one hand cylindrical internally and externally frustoconical, and on the other hand elastically transverse, and furthermore housing, internally, a sleeve (6) of elastic material of external diameter corresponding to the internal diameter of said ring ( 4), and of inner diameter slightly greater than the outer diameter of the tube (5) of smaller diameter. 2) Device according to claim 1 characterized in that the frustoconical end portion (40) of the ring (4) is divided longitudinally into blades (41) spaced apart. 3) Device according to claim 1 or claim 2 characterized in that the end (21) of the hollow part (2) located on the side of the tube (5) of smaller diameter is transversely flexible and has on its inner periphery to at least one notch (22) intended to cooperate with at least one corresponding notch (46) projecting externally and peripherally from the ring (4), at short 4) Device according to claim 1 or claim 2, characterized in that the end (21) of the hollow part (2) located on the side of the tube (5) of smaller diameter is transversely flexible and has on its inner periphery at least one notch (24) intended to cooperate with at least one corresponding notch (47) projecting externally and peripherally from the ring (4), at a short distance from the frustoconical end portion (40), in order to maintain said ring (4) ) in position relative to said hollow part (9). 5) Device according to any one of the preceding claims characterized in that the tube (5) of smaller diameter has at its end (50) inserted into the other tube (3), a plug (7) of plastic material, a portion (70) protruding beyond said end (50) of the tube (5), said portion (70) being transversely elastic and of a diameter slightly greater than the inner diameter of said tube (3) of larger diameter. 6) Device according to claim 5, characterized in that the portion (70) of the plug (7) is made of several branches (71) elastically transversely flaring so as to exert pressure on the inner wall (31) of the tube (3) of larger diameter.