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Title:
A SYSTEM FOR LOCKING AN OPERATING ARM OF A TIRE CHANGING MACHINE
Document Type and Number:
WIPO Patent Application WO/2016/185371
Kind Code:
A1
Abstract:
A system for locking the operating arm (4) of a tire changing machine comprising: a first sleeve (2) with a horizontal section (3) of the operating arm (4) slidably mounted therein, the sleeve being mounted to the upper end of a support column (1) of the tire changing machine, said sleeve (2) having a front end (2a) which faces connection means for work tools (5) and an opposite rear end (2b); a locking unit (10) for locking the sliding movement of the horizontal section (3) which is movably mounted to said first sleeve (2) and transversely slidable between an inactive position and an active position in which it locks the sliding motion and vice-versa; actuator means (27) for actuating said locking unit (10); said locking unit (10) being mounted at said front end (2a) of said first sleeve (2).

Inventors:
INCERTI, Paolo (Via dei Ciliegi 1, Correggio, 42015, IT)
Application Number:
IB2016/052845
Publication Date:
November 24, 2016
Filing Date:
May 17, 2016
Export Citation:
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Assignee:
FERRARI, Gino (Via Ascari 8, Correggio, 42015, IT)
MAIOLI, Franco (Via Monache 2, Xcorreggio, 42015, IT)
International Classes:
B60C25/132; B60C25/138
Foreign References:
DE2416668A11974-11-07
US5226465A1993-07-13
IT1033997B1979-08-10
JP2007008420A2007-01-18
Attorney, Agent or Firm:
BERGAMINI, Silvio (Maroscia & Associati Srl, Piazza del Castello 26, Vicenza, 36100, IT)
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Claims:
CLAIMS

1 . A blocking system of the operative arm (4) of a tire changing machine comprising:

A first sleeve (2) wherein an horizontal section (3) of the operative arm (4) and arranged on the upper end of a support column (1 ) of the tire changing machine, said sleeve (2) having a front end facing fastening means of work tools (5) and an opposing rear end (2b);

At least a blocking arrangement of the sliding of the horizontal section (3) which is movably associated with said first sleeve (2) and transversally sliding between an deactivated position and an activated blocking position of the sliding and vice-versa;

Actuating means (27) of said blocking arrangement; characterized in that said at least one blocking group (10) is fitted in correspondence with said front end (2a) of said first sleeve (2).

2. A system as claimed in claim 1 , wherein said at least one blocking arrangement comprises:

A first support plate (1 1 ) associated with said front end (2a) of the first sleeve (2) and having a thickness (S);

A shaped cavity (19) obtained in said thickness (S);

- An axial shaped opening (12) that is passed-through by said horizontal section (3);

A blocking element (20) mounted closely to a first side (1 1 a) of the plate (1 1 ) and sliding inside the shaped cavity (19) transversally to said horizontal section (3) between a blocking position and an un-blocking position of the latter, actuated by said actuating means (27);

Anti-friction means (34) whereon said horizontal section (3) rests slidingly, closely fitted to a second side (1 1 b) opposing said first side (1 1 a); and

A second closing plate of said cavity (19) matching associated with said first plate (1 1 ).

3. A system as claimed in claim 2, wherein said actuating means comprise.

At least one pushing body (25) actuated by an actuating group (27, 29) between an active pushing position in contact with said blocking element (20) and a inactive position moved away from the latter, and vice- versa;

A passage (24) obtained in said first side (1 1 a) through which said pushing body (25) passes.

4. A system as claimed in claim in anyone of preceding claims, wherein said blocking element (20)comprises at least one side (22) to contact and to push said horizontal section (3) which has a profile that can be matched with a peripheral profile of said horizontal section (3).

5. A system as claimed in claims 3 and 4, wherein said pushing body comprises an eccentric element (25) rotatingly supported around a rotation axis on said front end (2a) of the first sleeve (2) by bracket means (26) and having a peripheral contact surface with said blocking element (20) sliding inside said passage (24) obtained in said first side (1 1 a).

6. A system as claimed in claim 2, wherein said anti-friction means comprise:

At least one support bracket (31 ) housed in said cavity (19) near said second side (1 1 b);

At least one freely rotating element (34) supported on said support bracket (31 ) and on whose outer surface said horizontal section is normally resting.

Description:
A SYSTEM FOR LOCKING AN OPERATING ARM OF A TIRE CHANGING MACHINE

Field of the invention

The invention relates to a system for locking an operating arm of a tire changing machine, which is generally designed to lock the operating arm with the utmost accuracy, to prevent any undesired movement during locking.

Background art

The operating arm of a tire changing machine has a horizontal section that is supported in cantilever and slidable fashion inside a sleeve.

This sleeve is in turn supported at the top of a support column which extends vertically upwards from a base of the tire changing machine, upon which a horizontal motorized turntable is also mounted, for vehicle wheels to be laid and fastened thereto, such that tires may be mounted and removed to and from respective rims.

The horizontal section of the operating arm supports, at its free, or distal, end, with respect of the column, a second vertical sleeve, in which a stem is coaxially and slidably mounted, and is equipped, at its lower end, with a quick connect-release device for connecting and releasing the tools that are typically used by tire repairers to mount and remove tires to and from respective rims.

The position of the tools relative to the rims is of critical importance to avoid contact therebetween, because should such contact occur in spite of the care taken by tire repairers, the rims would be damaged.

For this purpose, the work tool must be positioned with the utmost accuracy relative to the rim, and namely on the tire bead, by appropriately maneuvering the horizontal section of the operating arm in the horizontal plane and the stem in the vertical direction.

Once the proper position of the work tool has been reached, the movement of both the horizontal section of the operating arm and the stem are locked by appropriate locking devices.

For this purpose, locking devices are known which comprise guillotine members mounted both at the rear end of the sliding sleeve, with the rear end designating the end opposite to the one that faces the work tool, and between the second vertical sleeve and the stem.

Particularly, these guillotine members consist of sturdy plates of adequate thickness, that are slidably supported and guided transverse to the horizontal section and to the stem respectively.

These plates have respective through openings extending therethrough at their center, whose inner edges form concave profiles substantially corresponding to the outer peripheral profiles of the horizontal section and the stem.

The concave profiles are slightly wider than those of the horizontal section of the operating arm and the stem, typically by a few millimeters, such that when no locking is required, a small peripheral clearance is typically defined between the horizontal section, the stem and the respective inner profiles of the plates.

Such clearance allows the horizontal section to be displaced relative to the sleeve and the stem to be displaced relative to the vertical cylindrical body, for proper orientation of the work tool with no friction being appreciably generated.

When both the horizontal section and stem are required to be locked, both locking plates are caused to slide a few millimeters transverse to the horizontal section and the stem, from a non-interference position, to an active locking position, for example by the action of a fluid-dynamic actuator with which the tire changing machine is equipped.

Such sliding movement causes a pressing contact between the inner edges of the respective openings on the outer surfaces of the horizontal section and the stem, thereby acting thereupon exactly as guillotines.

The contact between the inner edges and the outer edges of the horizontal section and the stem will frictionally prevent any further sliding movement thereof, thereby stably fixing the position that has been reached by the work tool mounted to the lower end of the stem, relative to a tire of a rim mounted to the rim.

Typically, these plates are mounted with the arrangement that, as they slide between the inactive and the active locking position, they can cause the horizontal section and the stem to move back a few tenths of a millimeter to certainly avoid any contact that might occur in spite of the care taken by the tire repairer in reaching the desired position.

This prior art is affected by a drawback.

Namely, the clearance, though of the order of a few millimeters, that exists between the inner edges of the openings, particularly the opening of the plate through which the horizontal section of the operating arm slides causes, in the locking configuration, a small rotation in a vertical plane of the horizontal section relative to the sleeve in which it is slidably received, due to the moment stress generated between the pressing plate and the sleeve as the work tool presses on the bead of a tire, which in turn generates an upward reaction that will be released to the distal end of the horizontal section of the operating arm, through the tool, the stem and the second sleeve.

Furthermore, this rotation is enhanced by the fact that the locking plate is placed, as mentioned above, at the rear end of the sleeve which becomes, in practice, its fulcrum.

As a result, the stress released on the distal end of the horizontal section, undesirably moves the latter upwards, thereby also causing the second sleeve of the stem to be rotated and the tool to dangerously move near the outer edge of the rim.

Furthermore, the position of the plate relative to the sleeve defines a sensitive length of the lever arm between the unit comprising the second sleeve, the stem, the tool and the rear end of the first sleeve, where the sliding locking plate is mounted.

This will proportionally increase the moment stress to be counteracted by the horizontal section of the operating arm, during both debeading and beading of the tire relative to the rim. Disclosure of the invention

The invention has the object to obviate the above described prior art problems.

Another object of the invention is to provide a system for locking the operating arm of a tire changing machine that can prevent any rotation of the horizontal section of the operating arm relative to the jacket in which it is slidably mounted, thereby causing the work tools to reach the locked position with higher accuracy.

A further object of the invention is to provide a system for locking the operating arm of a tire changing machine that can considerably reduce the moment stresses released on the horizontal section of the operating arm of a tire changing machine.

In one aspect the invention relates to a system for locking the operating arm of a tire changing machine as defined by the features of claim 1 .

Further features are described in the dependent claims.

The invention affords the following advantages:

- limiting the rotation of the operating arm of a tire changing machine as its sliding movement is locked once it has reached the operating position;

- considerably reducing the bending moment stresses released on the operating arm as a reaction when a work tool acts in contact with a tire bead, in both pushing and pulling directions.

Brief description of the drawings

Further characteristics and advantages of the invention will be more apparent from the detailed description of a few preferred, non-exclusive embodiments of a system for locking the operating arm of a tire changing machine, which is shown as non-limiting example in the annexed drawings, in which:

FIG. 1 is a highly schematic lateral view of a known system for locking the operating arm of a tire changing machine;

FIG. 2 is a highly schematic lateral view of a system for locking the operating arm of a tire changing machine according to the invention;

FIG. 3 is an enlarged broken perspective view of the locking system of Figure 2;

FIG. 4 is a further enlarged broken perspective view of the locking system of Figure 2;

FIG. 5 is a schematic and longitudinal sectional view of a portion of the locking system of the invention;

FIG. 6 is a corresponding top view of the portion of Figure 5;

FIG. 7 is a schematic front view of the interior of a first plate which is part of the locking system of the invention;

FIG. 8 is a schematic front view of the first plate of Figure 7.

Detailed description of a preferred embodiment

Referring to the above mentioned figures, numeral 1 designates a column that extends vertically upwards from a base (not shown) of a tire changing machine.

A first axially hollow horizontal sleeve 2 is supported at the top of the column 1 , and the horizontal section 3 of an operating arm 4 of the tire changing machine is slidably received therein.

The sleeve 2 defines a front end 2a and an opposite rear end 2b, with the term "rear end" designating the end normally opposite to the one that faces a work tool 5 that is supported to the vertical section 6 of the operating arm 3.

Referring to Figures 1 and 2, the former shows a prior art embodiment of a locking system for the horizontal section 3 of the operating arm 4, whereas the latter shows an inventive embodiment thereof.

As shown, in Figure 1 an arrow "F1 " designates a transverse force which, when enabled, acts on the horizontal section 3 and locks its sliding movement inside the sleeve 2, and when disabled, allows the horizontal section to freely slide therein.

Also referring to Figure 1 , an additional arrow "F2" designates a reaction force that is generated when the tool rests on and presses a lateral bead of a tire (not shown and known to the skilled person), thereby overcoming its elasticity, e.g. when debeading a tire from a rim of a vehicle wheel to remove it, and that axially stresses the vertical section 6, thereby generating a bending moment stress "M1 " that acts on the horizontal section 3 according to the length of the lever arm "b1 ".

The force "F1 " is generated by a pressure that is applied, in the prior art, at the rear end 2b of the sleeve 2 by means of a guillotine device "G" placed at said rear end, which can be actuated between an active position in which it locks the sliding movement of the horizontal section 3 and an unlocked position, and vice versa.

Referring now to Figure 2, it can be noted that the force "F1 " now acts at the front end 2a of the sleeve 2.

As a result, the lever arm "b2" defined between the two forces "F1 " and "F2" is considerably shorter than the lever arm "b1 ", which will generate a bending moment "M2" acting upon the horizontal section 3 with a considerably reduced value.

The skilled person will understand that this stress condition only occurs when the work tool 5 acts in contact with a tire, namely in contact with a lateral bead thereof, during debeading or as the tire bead is removed from the edge of a rim on which it is mounted: in the latter case, the force "F2" is exerted in a direction opposite to that of the former case.

More in detail, referring to the other figures, the force "F1 " appears to be generated by a locking system, generally designated by numeral 10 and hereinafter briefly referenced to as system 10, which, as mentioned above, is mounted at the front end 2a of the sieve 2.

Namely, the system 10 comprises a first quadrangular plate 1 1 which is fixed to the front end 2a transverse to a longitudinal axis "A" of the sleeve 2.

The plate 1 1 has therein a specially-shaped opening 12, here having a square shape, for the horizontal section to extend therethrough.

The latter, as shown, also preferably has a quadrangular cross section, here namely a square section, and is disposed with the bisectors 13 and 14 of the angles at the vertices respectively vertical and horizontal and perpendicular to each other.

In other words, the horizontal section 3 has two vertically arranged vertices 15 and 16 and two horizontally arranged vertices 17 and 18.

The plate 1 1 also has herein a recess 19 formed in its thickness "S" which forms a concave sliding seat, hereinafter referred to as concave seat 19.

A pushing body 20 is housed in the concave seat 19, and is slidably mounted, and actuated by an actuator unit 21 placed above the sleeve 2 using brackets "ST" bolted thereto.

The pushing body 20 has a concave contact front 22 whose profile mates the outer profile of the horizontal section 3.

Opposite to the contact front 22, the pushing body has a contact shank 23 projecting toward the actuator unit 21 and extending through an opening 24 formed for this purpose in the side 1 1 a that is deemed to be the top side of the plate 1 1 .

The shank 23 contacts the outer profile of a cam 25 which is rotatably supported above the sleeve 3 by two brackets 26.

The cam 25 is rotatably actuated by an actuating cylinder 27, normally a pneumatic cylinder, whose shaft 28 is articulated to the cam 25 by means of a pair of connecting rods 29.

A bracket 31 is placed in the recess 19, on the side that faces away from the pushing body 20, i.e. proximate to a side 1 1 b opposite to the side 1 1 a, which bracket defines a front 32 facing the opening 12 and following the half-profile thereof that faces toward it, and in which two seats 33 are formed.

Two rollers 34 are arranged in the seats 33 respectively, and freely rotate about respective rotation axes R1 and R2.

As shown in Figure 7, the profile of the front 32 of the bracket 31 is substantially aligned with the sides of the opening 12 and the rollers 34 have respective outer surfaces that slightly project inwards out of the edge of the opening.

This feature allows the horizontal section 3 to extend through the opening 12 and abut the rollers 34 to freely slide back and forth with low friction as compared to the sleeve 2, when its sliding movement is not locked by the system 10 and the guillotine unit "G".

Referring now to Figures 5 and 6, the actuating cylinder 27 is also shown to have a second shaft 50 extending away from the shaft 28, coaxially therewith, which can enable or disable a conventional guillotine device "G" mounted to the second rear end 2b.

The guillotine device "G", when needed, cooperates with the system

10 for locking the sliding movement of the horizontal section 3, namely to move the horizontal section a few millimeters back from the operator- selected position, before the sliding movement of the latter is finally locked.

The operation is as follows: when an operator is required to properly and accurately place a work tool 5 on a bead of a wheel tire arranged in a conventional manner on the work platform of a tire changing machine, he disables the system 10 and the guillotine device "G".

In this configuration, the horizontal section 3 of the operating arm 4 may freely slide inside the sleeve 2, extend through the opening 12 and rest upon the freely-rotating, i.e. idle, rollers 34.

When the operator determines, by maneuvering the operating arm 4, that the work tool 5 has reached its proper position, namely when it is placed on the lateral bead of the tire, near the edge of the rim, e.g. for debeading, he enables the actuating cylinder 27 and hence the system 10 and the guillotine device "G", which are both actuated at the same time.

More in detail, the shaft 28 enables the system 10 and the second shaft 30 enables the guillotine device "G".

The latter exerts a conventional pushing action, in a transverse direction, slightly inclined by a few degrees with respect to the perpendicular to the axis "A" of the horizontal section 3 proximate to the rear end 2b of the sleeve 2. This causes the horizontal section 3 to move a few millimeters back thereby preventing the work tool 5 from slipping toward the rim and accidentally hitting it as it presses on the bead.

Substantially at the same time, the shaft 28 pushes the cam 25 into rotation and, since the latter contacts the shank 23 of the pushing body 20, it will cause the latter to slide toward the horizontal section 3 until it rests thereupon with the contact front 22 which matingly couples with the outer profile of the horizontal section 3.

Such coupling generates the force "F1 " which keeps the horizontal section 3 locked in the position it has reached, until the operation step, i.e. the debeading step, has been completed.

As mentioned above, since the lever arm "b2" is shorter than the lever arm "b1 " defined according to the prior art, the bending moment stress "M2" that acts upon the distal end of the horizontal section 3 due to the reaction force "F2" is considerably smaller than the same bending moment stress "M1 " that would act in the prior art.

Furthermore, the albeit small rotation of the horizontal section 3 in the vertical plane occurring in prior art locking systems is actually eliminated, with the clearances between the sleeves 2 and the horizontal section 3 being considerably reduced and constant, as the latter constantly rests on the rollers 34 that prevent even the slightiest displacements thereof downwards, i.e. toward the base of the tire changing machine.

The invention has been found to fulfill the intended objects.

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

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

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.