EP4063563B1

EP4063563B1 - Grinding machine

Info

Publication number: EP4063563B1
Application number: EP22162385.3A
Authority: EP
Inventors: Claudio Favaron
Original assignee: Mecno Service Srl
Current assignee: MECNO SERVICE Srl
Priority date: 2021-03-24
Filing date: 2022-03-16
Publication date: 2023-05-10
Anticipated expiration: 2042-03-16
Also published as: IT202100007190A1; CN115125779A; ES2950874T3; EP4063563A1

Description

The present invention relates to a grinding machine particularly for the longitudinal profile of railway rails, railways and/or subways.
They are tangential grinding machines for restoring the longitudinal profile of the wheels.
Said known machines substantially comprise a base frame provided with wheels for resting on the railway rail, this frame supporting two further frames, each of which supports two motors to whose shafts a pulley is integral which rotates a grinding wheel whose circumferential surface rests on the longitudinal profile of the rail.
Drawbacks of these known machines consist in the fact that since the pitch between the two wheels is constant, an effective re-profiling of the rail is not ensured since the pitch between the two wheels could correspond to the pitch of the same irregularity of the wave.
To eliminate these drawbacks, a machine has been proposed which substantially comprises a base frame which supports a large number of tangential wheels (minimum 24, maximum 96) positioned in line without an electric motor. Thanks to the inclined wheel/rail contact with the rail, the high-speed towed wheels are able to rotate and work the undulations of the longitudinal profile of the rail by friction.
However, these known machines have other drawbacks and in particular:

low performance because the abrasive wheels are not equipped with electric/hydraulic motors;
a low quality finish due to the high working speed and low wheel revolutions;
low safety as the high working speed and the large number of wheels make them unstable on curves with a narrow radius or on tracks close to people or in an urban environment (tram);
a low suction efficiency of abrasive metal powders due to the high working speed.

EP 0 843 043 A1 discloses a grinding machine comprising several frames mounted on four wheels suitable to slide along rails. In a vertical movable subframe, two motors with respective grinding wheels are mounted. The respective positions of said grinding wheels may be varied.
The object of the invention is to eliminate these drawbacks and to provide a compact grinding machine with a reduced number of wheels for restoring the longitudinal profile of the rail which ensures effective processing of the same.
This object is achieved according to the invention with a grinding machine particularly for the longitudinal profile of the railway, tramway and/or subway rails as described in claim 1.
The present invention is further clarified hereinafter in a preferred embodiment thereof shown at purely illustrative and non-limiting purpose with reference to the attached drawing tables in which:

Figure 1: shows a side view of the grinding machine according to an invention during the transfer,
Figure 2: shows it at the start of processing,
Figure 3: shows it with the grinding wheels in contact with the rails,
Figure 4: is a side view of the grinding wheel motor unit,
Figure 5: shows it from above,
Figures 6 and 7: show the grinding wheels in a configuration with different spacing, and
Figure 8: shows the arrangement wheels for re-profiling the rail head.

As can be seen from the figures, the grinding machine according to the invention comprises a frame 2 mounted on four wheels 4 sliding along the rails 6 to be ground.
Mounted on said frame 2 is a frame 8 provided with wheels 10 for supporting and sliding along the rails 6, which frame is provided with two vertical axis pistons 12 for moving a frame 14.
In particular, said frame 14 comprises a shelf 20 provided at the end with arms 22 for articulation to the frame 8.
Two pistons 24 allow the lowering and lifting of the shelf 20 with respect to the frame 14.
Three plates 26 are provided on the shelf 20 on which are mounted three electric motors 28, 28', with parallel axes, to whose shaft 30 a pulley 32 is integral in rotation and is also connected to an underlying grinding wheel 34 provided under the shelf 20.
In particular, two of the plates 26 are fixedly mounted with respect to the frame 14 while the plate 26 which supports the motor 28' is translatably constrained to the frame 14 thanks to the presence in said plate of slotted holes 36 in which screws 35 are engaged which also engage the plate 26.
In a variant embodiment, all three plates are translatable with respect to the frame and can always be locked by engagement of the screws 35 engaging in the holes.

In a variant embodiment not shown in the drawings, the motor 28 and the grinding wheel driven by it can be translated horizontally by a mechanical hydraulic system or by a motorized system which determines the automatic variation of the center distance of the grinding units. To determine the number of wheels and relative wheelbase, the European grinding standards EN13231-3 must be followed, (see Tab 1 and Tab. 2):

Table 1 Approval criteria for the longitudinal profile expressed in terms of allowed percentages of exceedances:
Range of wavelengths (mm)	10-30	30-100	100-300	300-1000
Class 1	5%	5%	5%	5%
Class 2	No	10%	10%	No

	Table 2 Acceptance criteria for peak-to-peak limits
Wavelength range (mm)		10-30	30-100	100-300	300-1000
Peak-to-peak value limits (mm)		± 0.010	± 0.010	± 0.015	± 0.075

The operation of the machine according to the invention is as follows: once the frame 2, transported by the wheels 4 along the rails 6, has reached the area of the rail to be ground, the pistons 12 are operated so that the small wheels 10 rest on the rails 6.
The two pistons 24 are then actuated which cause the shelf 20 to descend until the grinding wheels 34 are positioned in contact with the upper surface of the rail.
The electric motors 28, 28' are then activated, which drive the wheels 34 in rotation, which grind the rail profile.
The wheels are positioned inclined and converging with respect to the base frame and the rail so that each wheel has its axis of rotation not parallel to the longitudinal running surface of the rail. Thanks to this arrangement, the grinding wheels wear according to a certain transversal profile during machining, regardless of the shape deformed by the rail.
In particular, thanks to the possibility that a wheel can change its position with respect to the other two wheels (centered or differently off-center), it allows to vary the wavelength of their processing.
To complete the transverse profile of the rail, two grinding units are required with at least 3 wheels each oriented with respect to the axis see figure 8.

Claims

Grinding machine comprising:
- a first frame (2) mounted on four wheels (4) sliding along the rails (6) to be ground,

- a second frame (8) provided with wheels (10) for supporting and sliding along the rails (6),

- means for vertical movement of said second frame (8) with respect to said first frame (2),

- a third frame (14), above the second frame (8), on which at least three electric motors (28, 28') with parallel axes are mounted, to each shaft of said motors (28, 28') a pulley (32) being integral in rotation with which the shaft of a grinding wheel (34) is also integral,

- means for vertical movement of said third frame (14) with respect to the second frame (8).
characterized by the fact that at least one of the three motors (28, 28') and the grinding wheel (34) rotoidally connected to it is horizontally translatable by means to determine the variation of the respective center distance between the three grinding units constituted by the motors (28, 28') and the corresponding grinding wheels (34).
Grinding machine according to claim 1 characterized in that said third frame (14) is provided at the end with arms (22) for articulation to the second frame (8).
Grinding machine according to claim 1 characterized in that the motors (28, 28') are mounted on plates (26) in turn supported by the third frame (14) and that the support (26) of the motor (28') is provided with slotted holes for engagement by screws (35) which also engage the third frame (14).
Grinding machine according to claim 1 characterized in that it comprises a mechanical hydraulic system which determines the automatic variation of the center distance of at least one grinding unit with respect to the others.
Grinding machine according to claim 1 characterized in that it comprises a motorized system which determines the automatic variation of the center distance of the at least one of the grinding units with respect to the others.