Tire demounting machine

Abstract

A tire demounting device includes a hook member having an elongate body that forms a hook at an end to be disposed lowerly and has a connection point at an opposite end, a pair of parallel plates having the hook member roto-translationally movable therebetween, a connection system that connects the plates to a support element, a drive system that moves the body between an inserted position to fit between a tire and the edge of a rim, and a removal position to remove the tire from the rim, the drive system being connected to the connection point, a connecting rod having one end hinged to the body and an opposite end hinged to the plates, so as to rotate parallel thereto along a circular arc path, the body having a pin, which is supported transverse and perpendicular to the plates, which have a specially shaped guide track for the pin.

Claims

1. A tire demounting device comprising: a hook (9) having an oblong body (10) shaping a lower hooked end (12) and having a joint point (13) at an opposing end; a couple of parallel plates (8) between which said hook (9) is movably fitted to move along a roto-translation trajectory; one or more fasteners coupling said plates to a support element (4); a moving member (5, 17) of said oblong body (10) between an inserted position, wherein said oblong body is interposed between a bead of a tire and an edge (B) of a rim (C), and an extracted position, wherein said oblong body extracts said tire from the rim (C), said moving member being connected with said joint point (13); a connecting rod member (18) having one end (18b) hinged to said oblong body (10) and an opposing end (18a) hinged to said plates (8), so as to rotate parallel to said plates along a circular arc trajectory, wherein said oblong body (10) comprises at least a pin (15) transversally and perpendicularly supported by said plates (8), and wherein said plates (8) are shaped to provide at least an outlined path (16) to guide said pin (15).

2. The tire demounting device as claimed in claim 1, wherein said moving member comprises: an actuator associated with said support element and having a reciprocating rod (5); a connecting element (17) interposed between said rod (5) and said joint point (13).

3. The tire demounting device as claimed in claim 1, wherein said path (16) is outlined as a convex arc facing said oblong body (10) and having a first segment (T1) having a first bending radius and a second segment (T2) having a second bending radius different from said first bending radius.

4. The tire demounting device as claimed in claim 1, wherein said oblong body (10) comprises a support arm (14) extending therefrom toward said path (16), said pin (15) being associated to a free end of said support arm (14).

5. The tire demounting device a claimed in anyone claim 1, wherein said support element comprises a work tools support stem (4) of a tire changing machine.

6. The tire demounting device as claimed in claim 2, wherein said movable rod (5) is guided by a guiding element (6) along said support element (4).

7. The tire demounting device as claimed in claim 1, wherein said path comprises at least a groove (16) obtained in at least one inner face of one of said parallel plates (8).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further characteristics and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a tire demounting device, which is shown as non-limiting example in the annexed drawings, in which:

[0035] FIG. 1 is a broken view of a part of a tire changing machine equipped with the tire demounting device of the invention;

[0036] FIGS. 2 to 5 are schematic lateral views showing the operating steps of the tire demounting device of the invention;

[0037] FIGS. 2a to 5a show the position of a hook member of the tire demounting device of the invention in the respective operating steps of FIGS. 2 to 5;

[0038] FIG. 6 is a front view of the tire demounting device of the invention, in an inserted position.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0039] Referring to the above mentioned figures, numeral 1 designates a vertical column of a conventional tire changing machine.

[0040] Numeral 2 designates a horizontal arm which is rotatingly articulated to the column 1 as is known by the skilled person.

[0041] The arm 2 has a free end 2a facing away from the column 1 and outwards, having a vertical sleeve 3 associated therewith, for a work tool-carrying rod 4 to coaxially and controllably slide therein.

[0042] A pneumatic cylinder (not shown) is associated with the rod 4, and has its shaft 5 mounted to slide relative to the rod 4, e.g. within the rod 4.

[0043] The latter has a longitudinal slot 6 in which a block 7 is slidingly guided, which block is rigidly joined to the shaft 5, so that it can be moved therewith.

[0044] Two parallel plates 8, here extending vertically, are attached to the lower end of the rod 4, and have a gap therebetween for a hook member 9 to be received therein, and move along a roto-translational path between an inserted position and a removal position.

[0045] The skilled person will understand that the term inserted position will designate a movement and a series of positions in which the hook is progressively fitted between the bead of a wheel tire and the edge B of the rim C upon which the tire is mounted, whereas the term removal position designates a movement and a position in which the hook member is progressively removed from the inserted position.

[0046] The hook member 9 has a elongate body which is slightly bent to form a knee 11 facing away from the rod 4, and has one end designed to be the lower end, i.e. the end facing the rim C, that forms a hook 12 and, one opposite end that has a connection point 13, here a hinge having a transverse axis.

[0047] Proximate to the connection point 13, the hook member 9 has a short extension 14, extending in cantilever fashion toward the rod 4 and supporting, at its free end, a transverse pin 15 with its opposite ends projecting out by respective sections 15a (see FIG. 6) relative to the body 10 of the hook member 9.

[0048] These ends 15a of the transverse pin 15 are guidingly engaged in two hollow tracks 16 formed to extend parallel to each other in the respective inner faces of the plates 8, and having arched profiles, with a first section T1 having a first bend radius, and a second section T1 having a second bend radius differing from the first bend radius, namely the first bend radius of the first section T1 facing the rod 4 being greater than the second bend radius of the second section T2 facing away from the rod 4.

[0049] The skilled person will nevertheless appreciate that the first section T1 and the second section T2 are seamlessly connected, to assist the sliding movement of the ends 15a.

[0050] A coupling rod 17 is interposed between the block 7 and the connection point 13, for transferring motion from the shaft 5 to the hook member 9.

[0051] Between the substantially middle area of the elongate body 10 and the lower areas of the plates 8, i.e. those facing the rim C and referenced 8a, the homologous ends 18a of a pair of connecting rods 18 are hinged, the latter having their opposite homologous ends hinged to the elongate body 19 at the knee 11, on each side of the latter, and can rotate about the ends 18a following a circular arc path.

[0052] The plates 8 define respective lower sides 8b, which are designed to rest on the rim C2 during the steps in which a bead of a tire with the edge B is being removed therefrom.

[0053] The operation of the tire demounting device is as follows: when a tire is to be removed from the rim C upon which it is mounted, the operator places the wheel on a self-centering device of a tire changing machine, i.e. on the rotating platform upon which the wheels are laid, once they have been deflated and debeaded, and are temporarily secured using fixation members that act upon the rim C thereby holding them in a horizontal or substantially horizontal position.

[0054] Once the wheel has been secured, the horizontal arm 2 of the tire changing machine is placed in such a position that the hook member 9 will be located at an insertion point between the tire bead and the edge B of the rim C.

[0055] At this time, the hook member 9 is held in a lifted position relative to the rim C.

[0056] The rod 4 is progressively lowered until the lower sides 8b of the plates 8 contact the rim C, as shown in FIGS. 2-5.

[0057] Then, the pneumatic cylinder is actuated and drives the shaft 5 to slide it toward the rim C relative to the rod 4, which remains in the previously established position.

[0058] The sliding movement of the shaft 5 actuates, through the block 7 and the connecting rod 17, the displacement of hook member 9 toward the rim

[0059] This displacement imparts a roto-translational movement to the hook member 9, allowing the latter to pass over the edge B of the rim C without touching it and to introduce the hook 12 for a predetermined section between the latter and the inner bead of the tire.

[0060] The roto-translational movement of the hook member 9 is obtained due to the combined movement of the elongate body 10 which is simultaneously guided by the sliding movement of the ends 15a of the pin 15 in the tracks 16, namely along the sections T1 and T2 thereof, and by the rotation of the connecting rod 18 interposed between the elongate body 10 of the hook member 9 and the plates 8.

[0061] In other words, the combination of the paths of the ends 15a of the pin 15 in the two sections T1 and T2 of the connecting rod 8 create a pair of forces, schematically referenced F1 and F2 in FIG. 5, which act upon the hinge points and impart a rotational movement to the elongate body 10 as a translational movement is imparted to the shaft 5.

[0062] The sum of these movements is the roto-translational movement that allows the hook member 8 to automatically and accurately introduce its hook 12 between the tire and the edge B.

[0063] Once the hook 12 has been fully introduced, by passing over the inner edge of the tire bead, i.e. its side wall, it is ready to engage the latter during a subsequent removal step.

[0064] For the removal step, the cylinder pulls the shaft 5 upwards and the hook 12 engages the inner edge of the side wall of the tire and progressively removes it from the rim C by causing it to pass over the edge B of the latter.

[0065] Again, in this removal step, the elongate body 10 of the hook member 9 follows a roto-translational path that prevents any contact thereof with the edge B, thereby protecting the integrity of the rim C.

[0066] FIGS. 2a to 5a clearly show the position of the elongate body 10 in both introduction and removal steps.

[0067] Once a section of the tire bead has been lifted and removed from the rim C, the operator may introduce a conventional demounting tool, referenced 19 in FIG. 5, into this section and, by rotating the self-centering device, he may remove the entire bead of the tire from the rim C upon which it is mounted.

[0068] The invention has been found to fulfill the intended objects.

[0069] The invention so conceived is susceptible to changes and variants within the inventive concept.

[0070] Also, all the details may be replaced by other technical equivalent elements.

[0071] In its practical implementation, any material, shape and size may be used as needed, without departure from the scope as defined by the following claims.