WO2014188326A1 - Lifting apparatus for moving vehicle wheels with respect to a balancing shaft of a balancing machine - Google Patents

Abstract

The lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine, comprises: a base (8); a lift platform (9) having a first self weight, which is mounted above the base with frame means (10) interposed therebetween, for vehicles wheel (3) having a second self weight to be loaded thereon, which is vertically movable relative to the base; a fluid-dynamic circuit (100) comprising fluid-dynamic means (11) for moving the platform (9) between a lowered position and a raised position; supply means (101) for supplying a pressurized fluid; means for controlling the supply means, which comprise: a fluid pressure regulator (114) interposed between the supply means (101) and the fluid-dynamic means (11); a detection unit (104) for detecting the platform (9) in the lowered position; a tank (108) for storing a balancing pressure that balances the total weight obtained by the sum of the first self weight and the second self weight.

Description

LIFTING APPARATUS FOR MOVING VEHICLE WHEELS WITH RESPECT TO A BALANCING SHAFT OF A BALANCING MACHINE

Field of the Invention

The invention relates to a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine, which is generally adapted to be used for lifting vehicle wheels from the ground to the height of the balancing shaft of a balancer machine without requiring the weight of the wheels to be completely lifted by an effort of operators, and a method of lifting a lift platform of a lifting apparatus from a starting height to an arrival height.

Background art

Lifting apparatus have been long known and used in combination with machines that are typically used by tire repairers both for mounting and demounting tires to and from rims, and for balancing wheels after tire mounting operations.

Particularly, these lifting apparatus are employed to avoid or at least reduce the physical efforts that tire repairers should be required to exert if there were no such apparatus, to lift the wheels from the ground to the height of the balancing shaft of a balancer machine and to discharge them at the end of the work operations.

Typically, these lifting apparatus basically consist of a base platform that is designed to rest on the ground, a lift platform over the base platform, which is designed to receive the wheels to be lifted and a controlled lifting system interposed between the two platforms, which is used to move the lift platform.

Certain types of lifts, namely those adapted to be functionally coupled to balancer machines, are also equipped with special systems that allow manual vertical displacements of the lift platform, especially during lifting, such that accurate alignment is ensured between the horizontal balancing shaft of a balancer machine and the central hole of the rim of a wheel to be mounted to the shaft in the vertical position. These special systems can compensate for the self weight of the wheels when these are loaded on the lift platform, thereby obtaining the practical effect that both self weights of the wheel and the platform on which the wheel is loaded are substantially eliminated.

This prior art suffers from certain drawbacks.

A first drawback is that certain prior art systems are designed to follow the movements of operators, i.e. to sense the stresses that the operators apply to the lift platform to move it in the vertical direction, and hence supply fluid to a fluid-dynamic unit for actuation thereof each time that a stress in the same direction is sensed, and only for the time during which such stress is maintained.

A second drawback is that prior art systems have structurally complex arrangements for counterbalancing the self weights of the wheels and the platforms on which the wheels are loaded, requiring a great number of parts and a control computer, as well as a special electronic program for management thereof.

A further drawback of the prior art is that certain prior art systems cannot account for the size of the items to be lifted, namely of the various diameters of the vehicle wheels and hence their use is limited.

Disclosure of the invention

The invention has the object to improve the prior art.

Another object of the invention is to provide a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine that allows effortless lifting of vehicle wheels irrespective of their diameters and self weights.

A further object of the invention is to provide a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine that has a considerably simplified construction as compared with the prior art systems that can counterbalance both self weights of the wheels and the platform on which the wheels are loaded.

Another object of the invention is to provide a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine that affords simple and reliable use, and has a lower cost than prior art lifting apparatus.

Yet another object of the invention is to provide a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine that may be functionally combined with any prior art or factory-new machine as may be used by tire repairers to lift vehicle wheels, especially balancer machines.

In one aspect the invention relates to a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine as defined by the characteristics of claim 1 .

In another aspect the invention relates to a method of lifting a lift platform of a lifting apparatus from a starting height to an arrival height as defined by the characteristics of claim 8.

The invention achieves the following advantages:

- effortlessly lifting vehicle wheels to a desired height;

- displacing the lifted wheels as needed while maintaining constant balancing between the combined weights of the latter and the platform and the lifting arrangement of the lifting apparatus;

- appreciably simplifying the structure of the lifting apparatus without affecting its performances;

- affording a competitive advantage to the lifting apparatus as compared with those of the prior art.

Brief Description of the Drawings

Further characteristics and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a lifting apparatus for displacing vehicle wheels relative to a balancing shaft of a balancer machine, which is shown as non-limiting example in the annexed drawings, in which:

FIG. 1 is a schematic perspective view of a lifting apparatus of the invention, in a lowered position and in which the vehicle wheel balancing machine is only denoted by a side wall thereof facing the lifting apparatus;

FIG. 2 is a perspective view of the lifting apparatus of the invention as viewed from a different angle from that shown in Figure 1 , and with a vehicle wheel in a lifted position toward the balancing shaft of a balancer machine;

FIG. 3 is a perspective view of the lifting apparatus of the invention as viewed from a different angle from that shown in Figure 2, and with a vehicle wheel in a lifted position as it is guided for fitting the central hole of the rim onto the balancing shaft of a balancer machine;

FIG. 4 is a block diagram of the pneumatic circuit through which pressurized fluid is carried for actuation of the lifting apparatus of the invention.

Detailed description of a preferred embodiment

Referring to the above mentioned figures, numeral 1 generally designates a lifting apparatus that is designed to be placed close to a side 2 of a balancer machine for vehicle wheels 3, with a balancing shaft 4 that extends outwards from the side 2 and is part of a spindle 5 rotating about an axis of rotation that coincides with the longitudinal axis of the balancing shaft 4.

As shown in the figures, the spindle 5 has a backing flange 6 against which the central portions 107 of the rims 8 of the wheels 3 are designed to abut for balancing.

The lifting apparatus 1 , hereinafter simply referred to as lift 1 , comprises a base 8 that rests on the ground, a lift platform 9 which is designed to receive the wheels 3 to be lifted and a scissors frame 10 which connects the base 8 and the platform 9 together, such that the latter can move up and down relative to the base 8.

The platform 9 is moved by means of a pneumatic actuator 1 1 , whose housing is hinged to the base 8 via a hinge 12 supported by two vertical brackets 13 and the distal end of the shaft 14 having rollers 15 freely rotating about a horizontal axis of rotation, resting between the upper profile of a ramp 16 and a pair of arms that form the cross-shaped frame 10 and are referenced 10, whereas the other pair of arms is referenced 18.

The ends of the two pairs of arms 17 and 18 are attached between the base 8 and the platform 9, namely with the concurrent ends 17a and 18a hinged to the base 8 and the platform 9 respectively and the opposite ends 17b and 18b sliding in guided fashion on the base 8 and the platform 9.

More in detail, Figures 2 and 3 show that the ends 18b have a transverse pin 19 slidingly engaged in the slot of a straight guide 20 formed in a rib 21 raising from the base 8.

Referring to Figures 1 to 3, it is shown that a slide 22 is mounted to the platform 9 to slide toward or from the balancing shaft 7 and has a grip and operating handle 23 which also acts as a support for maintaining the wheel 3 in a substantially vertical position, as shown in Figure 2.

The lift 1 has a ramp 24, which is fixed to the base 8 to facilitate mounting and removal of wheels 3 to and from the platform 9 when the latter is in the fully lowered position.

The lift 1 also comprises a protection barrier 25 facing the operator standing area during operation, which prevents the operator from dangerously coming close to the operating members, particularly moving members, e.g. the frame 10 and the platform 9.

Referring to Figure 4, a diagram of the pneumatic circuit 100 for actuating and controlling the lift 1 of the invention is shown.

More in detail, the circuit 100 comprises a pressurized air source 101 which is connected to a selector 102 via a pneumatic line 103.

The selector 102 is in turn connected to a position detector 104 via the same line 103.

This detector 104, which has an open position "a" and a discharge position "b", is arranged (see Figure 3) on the base 8, under the end of one of the arms that form the scissors frame 10, namely the end 17a of the arm 17, and can detect the lowered or raised position of the arm 17, and hence of the lift 1 .

The detector 104 is also connected via two pneumatic lines 106 and 107 to a normally closed stop valve 105, which has an open position "a" and a closed position "b" and can only be opened when it receives an open command from the detector 104.

The valve 105 is in turn connected via a pneumatic line 109 to a tank

108 containing a volume of pressurized air.

The tank 108 has an output pneumatic line 1 1 1 which connects it to a discharge valve 1 12, also having an open position "a" and a discharge position "b", which is connected via a pneumatic line 1 13 to a pilot-operated pressure regulator 1 14.

This pressure regulator receives pressurized air directly from the source 101 via a pneumatic line 1 15 and sends it to the pneumatic actuator 1 1 via a pneumatic line 1 16 having mounted thereto a valve 1 17 and, downstream from this valve, a quick-discharge valve 1 18, which is adapted to be actuated for overpressure discharge.

The valve 1 17, which also has an open position "a" and a discharge position "b" and is normally in the position "a", receives pressurized air from the source 101 via a pneumatic line 1 19 which branches off from the pneumatic line 103 and has a second selector 120 mounted thereto for controlling the lowering movement of the platform 9.

The operation of the lift 1 is as follows: the platform 9 is at the start of an operating cycle when it is in its fully lowered position.

The operator loads a wheel 3 in a vertical position on the slide 22 and actuates the selector 102 on the control panel of the lift 1 , which is schematically designated in Figure 4 with broken lines "PU", into the closed position, as outlined by broken line 102'.

In this position, the pressurized air delivered by the source 101 reaches the detector 104 which is maintained in the open position "a" by contact with the platform 9, which is in the lowered position.

Therefore, the compressed air reaches the valve 105 and switches it from the closed position "b" to the work position "a", which allows compressed air to flow toward the tank 108 and progressively accumulate therein, thereby causing a corresponding progressive increase of pressure.

Pressurized air flows through the pneumatic lines 1 1 1 and 1 13 and the general discharge valve 1 12, which is typically in the open position "a", and reaches the pressure regulator 1 14 which sends it, at a progressively increasing pressure, to the pneumatic actuator 1 1 via the pneumatic line 1 16 and through the valve 1 17 which is normally open in the position "a" and also through the quick-release valve 1 18, which is also normally open.

The piston 125 of the fluid-dynamic actuator 1 1 is subjected, through the shaft 126, to the resistance force generated by the combined weight of the platform 9 and the wheel loaded thereon, and only starts to lift the platform 9 when air pressure in the thrust chamber 128 reaches such a value as to progressively oppose such resistance force until it balances it.

Once the platform 9 has completed a first lifting step, the detector 104 loses contact with the platform and moves to the position "b", where it blocks the passage of compressed air along the pneumatic line 106.

As a result, the valve 105 is no longer under the stress of fluid pressure in the pneumatic line 106, and moves back into the closed position "b", whereby air in the tank 108 has a stored pressure value corresponding to the pressure value that balances the resistance force generated by the self weights of the platform 9 and the wheel 3 loaded thereon.

In this balanced state, the piston 125 stops its movement and the platform 9 is stopped in a floating position.

In order to bring the wheel 3 level with the balancing shaft 4 for the central hole 203 of the rim 7 to fit thereon, the operator lifts the platform 9 by hand.

This lifting motion moves the piston 125 in the housing 127 and increases the volume of the thrust chamber 128 thereby drawing additional pressurized air, which is supplied by the source 101 through the pneumatic line 1 15.

Therefore, the operator may easily and effortlessly lift the platform 9 and the wheel 3 loaded thereon, whose weight is balanced, to the desired height in which the hole 203 and the balancing shaft 4 are aligned.

Then, the operator moves the slide 22 toward the balancing shaft 4 for the wheel to be pulled thereupon and be attached to the flange 6 in a known manner.

Before starting the balancing step, the operator instructs to lower the platform 9 to the ground.

For this purpose, he/she acts upon the selector 120 which opens communication between the source 101 and the valve 1 17 via the pneumatic line 1 15.

As the valve 1 17 is under the pressure of the air supplied from the source 101 , it switches from the open position "a" to the discharge position "b" and the thrust chamber 128 is progressively emptied, thereby causing the descent of the piston 125 and hence the platform 9.

It shall be noted that, in this step, the tank 8 still contains compressed air at the balancing pressure.

As soon as the operator has completed the balancing step on the wheel 3, he/she instructs to lift the platform 9 toward the wheel 3 such that it may be loaded again on the slide 22 and moved back down onto the ground.

In order to actuate this lifting movement, the operator acts upon the selector again 120, to switch it to the position opposite to the lowering position.

This will stop compressed air supply to the valve 1 17, which will move back into the open position "a", thereby allowing pressurized air to flow toward the thrust chamber 128 of the fluid-dynamic actuator 1 1 .

Then, the piston 125 moves up again, and pushes the platform 9 with it, to the level of the wheel 3 and, when the slide 22 supports the wheel 3 again, it restores the above mentioned balanced state.

In this state the operator may effortlessly remove the wheel 3 from the balancing shaft 4 and retract the slide 22 away from the latter.

Then, the operator will instruct to lower the platform 9 to carry the wheel 3 back to the ground and discharge it from the slide 22. For the platform 9 to be lowered again, the operator actuates the selector 120 and moves it to the closed position, as shown in Figure 4 by the broken line 120'.

In this position, the pneumatic line 1 19 supplies pressurized air to the valve 1 17 again, and the latter is moved back into the discharging configuration "b", thereby progressively emptying the thrust chamber 128 and thus lowering the piston 125 and the platform 9.

When the operator has to lift a new wheel 3 having a different size and weight from those of the previous wheel, he/she will discharge the pressurized air held within the tank 108.

In order to do this, he/she will act upon the general discharge valve 1 12 to switch it into the discharging position "b".

In this position, the pneumatic line 1 1 connects the tank 108 with the discharge, thereby causing it to be substantially emptied, and the circuit 100 is ready for a new lifting and balancing step, which is repeated with a new balancing pressure that will balance the self weights of the platform 9 and the new wheel 3 loaded thereon.

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.

Claims

1 . A lifting apparatus for moving vehicle wheels (3) with respect of a balancing shaft (4) of a balancing machine (2), comprising:

- A resting base (8) on the ground;

- A lifting platform (9) having a first typical weight and which is fitted over said base (8) with interposed frame means (10), on which vehicles wheel (3) having a second typical weight can be loaded and which is movable with respect of said base (8);

- A fluid-dynamic circuit (100) comprising:

- Fluid-dynamic alternately moving means (1 1 ) of said platform (9) between a lowered position and a raised position;

- Feeding means (101 ) of said moving means (1 1 ) by a pressurized fluid;

- Control means of said feeding means (101 );

characterized in that said control means comprise:

- a pressure adjusting unit (1 14) of said pressurized fluid, interposed between said feeding means (101 ) and said fluid-dynamic moving means (1 1 );

- a detecting unit (104) of said platform in at least said lowered position;

- a storage unit (198) of a balancing pressure balancing a total sum weight of said first typical weight and second typical weight, interposed between said detecting unit (104) and said adjusting unit (1 14).

2. An apparatus as claimed in claim 1 , wherein said storage unit comprises a containing tank (108) of said fluid at said balancing pressure.

3. An apparatus as claimed in claim 1 or 2, wherein said fluid-dynamic circuit comprises a first discharge unit (1 12) of said storage unit (108) and adjusting unit (1 14).

4. An apparatus as claimed in anyone of preceding claims, wherein said fluid-dynamic circuit comprises a second discharge unit (1 18) of said fluid-dynamic moving means (1 1 ).

5. An apparatus as claimed in anyone of preceding claims, wherein control means ((102, 120) designed to control said moving means (1 1 ) are interposed between said feeding means (101 ) and detecting unit (104).

6. An apparatus as claimed in claim 1 , wherein a direct constant feeding line (1 15) at a pressure different from said balancing pressure is fitted between said feeding means (101 ) and said adjusting means (1 14).

7. An apparatus as claimed in claim 1 , wherein said platform (9) comprises slide guided means (22) sliding on the latter and defining a support surface of said wheel toward, or from, said balancing shaft (4).

8. A lifting method of a lifting platform (9) of a lifting apparatus (1 ) from a starting height up to an arrival height, comprising the steps of:

- to set said lifting platform (9) at said starting height and load a wheel to be balanced on said platform (9);

- to feed lifting means (1 1 ) of said platform (9) in a first lifting step;

- to detect said first step by detecting means (104);

- to maintain the feeding of said lifting means (1 1 ) by a fluid at a balancing pressure, so that to create a balancing strength of a total weight which is the sum of own weights of said platform (9) and of said wheel (3);

- to store said balancing pressure in a storage unit (108);

- to push said platform (9) up to said arrival height by a strength slightly greater than said balancing strength.