FR2782992A1 - Pneumatically controlled expandable and retractable shaft for interlocking reel, has tube with slots having cotter pins extracted by bladder inflation - Google Patents

Abstract

The shaft comprises a tube (1) in which there are regularly distributed peripheral slots (12). From each slot a cotter pin (4) can be extracted under the inflation action of a bladder (3) arranged axially in the tube. An elastically deformable tubular casing (5) prevents the cotters from falling into the tube during the removal of the bladder through one end of the tube.

Description

The subject of the present invention is an expandable shaft device and

  pneumatically retractable

  for securing a drum, or the like.

  Pneumatic expandable and retractable shaft devices are already known, which make it possible to automatically secure a reel which there

is engaged.

  Such an expandable and retractable shaft device is generally in the form of a tube which has at each of its ends a nozzle intended to be placed in a bearing, and on the surface of the openings regularly distributed peripherally, and which can be extract the keys in the radial direction, by swelling a bladder contained in the tube, in order to secure the rotation of the reel engaged on

the tube.

  After deflation of the bladder, the keys return to the tube by elastic return, which releases the

  reel, which can then be removed.

  The bladder may eventually leak, which requires repair or replacement. The bladder is then extracted by one of the ends of the tube after removal of a tip, with the disadvantage of the fall of the keys in the tube, which complicates delivery.

in place of the bladder.

  To overcome this drawback, special tools are used to hold the keys from the outside, and which consist of jumpers screwed onto the keys, which for this purpose have a threaded hole, and capable of bearing on the tube. However, only the manufacturer has these special tools, so that repair or replacement of a bladder necessarily involves a return to the manufacturer, which is

detrimental to the user.

  The object of the present invention is to propose an expandable and retractable shaft device with control

  pneumatic to overcome this drawback.

  The pneumatically retractable expandable shaft device according to the invention comprises a tube in which are made, in the longitudinal direction and regularly distributed peripherally, slots from each of which a key can be extracted under the action of the swelling d 'a bladder disposed axially in said tube, and it is essentially characterized in that it internally comprises a means making it possible to prevent said keys from falling into said tube during

  removing said bladder through one end of said tube.

  According to a particular embodiment of the device according to the invention, it comprises a tubular envelope made of an elastically deformable material, placed in the tube, and the wall of which is inserted between the keys and the bladder, the latter

  being introduced axially into said tubular casing.

  When removing the bladder, the keys all come, under the effect of the elastic return, to bear against the tubular envelope which thus substantially retains its tubular shape, which prevents said keys from falling into the tube, and allows the restoration

place of said bladder.

  When the bladder swells, the tubular envelope, due to its elasticity, deforms which

allows the release of the keys.

  The advantages and features of the present invention will become more apparent from the

  description which follows and which relates to the appended drawing,

  which represents a non-limiting embodiment thereof.

  In the accompanying drawing, the single figure represents a partial view in longitudinal section of an expandable and retractable shaft device according to the invention. In this figure we can see that an expandable and retractable shaft device according to the invention comprises a tube 1 closed at its two ends by end pieces 2 which

  they are secured by means of screws, not shown.

  The tube 1 axially encloses a bladder 3 of tubular shape, each of the ends 30 of which is crimped, in a leaktight manner, by means of a nozzle 31 taking place inside the end of the bladder 3 and of a cover 32 which covers it and which is secured to the end piece 31

by means of a screw 33.

  Each of the covers 32 is housed in one of the end pieces 2, while the end pieces 31 are kept at a distance from each other by an openwork connecting tube 34

which is united to them.

  On the other hand, the tube 1 laterally comprises, near one of its ends, a valve connection 10 for supplying pressurized air, in connection with the interior of the bladder 3 by means of a channel 35 made axially in a screw 33, and intended to allow

swelling of the bladder 3.

  The wall 11 of the tube 1 is provided with slots 12 made in the longitudinal direction and regularly distributed peripherally. In each of the slots 12 is engaged a key 4, which is movable therein in the radial direction so as to be able to extract itself from the tube 1 during the inflation of the

bladder 3.

  The tube 1 also contains a tubular envelope 5, freely disposed between the end pieces 2 around the bladder 3. The tubular envelope 5 is made of a deformable elastic material in order to allow the bladder 3 to swell, and therefore the extraction of the keys 4. The tubular casing 5 can be produced in

  a material such as natural or synthetic rubber.

  The keys 4 are each provided with a sole 40 which bears against the tubular casing 5, while leaf-shaped springs 41 push the key 4 towards the inside of the tube 1, being interposed between the soles 40 and the inner face 13 of the wall

11 of tube 1.

  To repair or replace the bladder 3, remove a tip 2, then extract from the tube 1 the assembly formed by the bladder 3, the tips 31, the covers 32 and the connecting tube 34. Under the effect of the springs 41 the keys enter the tube 1 without, however, leaving the slots 12, since they are retained by the tubular casing 5 which, although elastically deformable, is of a certain rigidity to substantially maintain its tubular shape under the push

keys 4.

  In addition, as the keys 4 are regularly distributed around the periphery of the tube 1, they exert on the tubular casing 5 radial forces which contribute to the fact that the tubular casing retains

substantially its tubular shape.

  After repair or replacement of the bladder 3, the assembly formed by the bladder 3, the end pieces 31, the covers 32 and the connecting tube 34, is introduced into

  the tube 1 passing through the tubular envelope 5.

  It will be noted that advantageously the tubular envelope 5 constitutes a protection of the bladder 3 against

  possible attacks on the keys 4.

  It goes without saying that the present invention does not

  cannot be limited to the foregoing description of one of

  its embodiments, capable of undergoing a certain number of modifications without departing from the scope of the invention.

Claims (5)

  1) Pneumatically expandable and retractable shaft device for securing a reel or the like, of the type comprising a tube (1) in which slots (12) are formed, in the longitudinal direction and regularly distributed peripherally each of which can extract a key (4) under the action of the inflation of a bladder (3) disposed axially in said tube (1), characterized in that it internally comprises means (5) making it possible to prevent said keys (4) falling into said tube (1) upon removal of said   bladder (3) by one end of said tube (1).   2) Device according to claim 1, characterized in that it comprises a tubular envelope (5) made of an elastically deformable material, placed in the tube (1), and the wall of which is interposed between the keys (4) and the bladder (3), the latter being   introduced axially into said tubular casing (5).   3) Device according to claim 2, characterized in that the tubular casing (5) is made   natural or synthetic rubber.   4) Device according to any one of   previous claims, characterized in that each   keys (4) have a sole (40), and in that leaf-shaped springs (41) are interposed between   said sole (40) and the wall (11) of the tube (1).   ) Device according to any one of   previous claims, characterized in that the bladder   (3) is tubular, each of its ends (30) is crimped, in a leaktight manner, by means of an end piece (31) taking place inside the end of the bladder (3) and a cover (32) which covers the latter and which is secured to said end piece (31) by means of a screw (33), while said end pieces (31) are kept at a distance from one of   the other by a connecting tube (34) which is secured to them.   6) Device according to any one of   previous claims, characterized in that the tube   (1) has at each of its ends a tip (2) which can be secured to it by means of screws. 7) Device according to claim 1, characterized in that the tube (1) laterally comprises near one of its ends a valve connection (10) for supplying pressurized air, in connection with inside the bladder (3).