Device for detecting the position of a glass sheet movable along a transport direction on a grinding machine and related grinding machine

Abstract

A grinding machine (1) for processing a glass sheet (L) movable along a horizontal transport direction (X), comprising a control unit, at least one tool unit (3, 3A, 3B) movable along a direction (Y) transverse to said transport direction (X) of the glass sheet (L) and having a spindle (12, 12A, 12B), and a detection device (4, 4A, 4B) associated with the tool unit (3, 3A, 3B) and adapted to detect the position of the glass sheet (L) along said transport direction (X). The detection device (4, 4A, 4B) comprises a slider (5, 5A, 5B) movable along a guide direction (C) and bearing a pad (6, 6A, 6B) for contact with an edge of said glass sheet (L), an actuator (7, 7A, 7B) for moving said slider (5, 5A, 5B) along said guide direction (C), and a linear position transducer (8, 8A, 8B) for detecting the position of said slider (5, 5A, 5B) along said guide direction (C). The actuator (7, 7A, 7B) is mounted on an adjustable support (9, 9A, 9B) adapted to move said slider (5, 5A, 5B) reversibly from a first position in which said pad (6, 6A, 6B) is vertically spaced from the movement plane of said glass sheet (L), so as not to interfere with the movement of said glass sheet (L), to a second position in which said pad (6, 6A, 6B) is arranged transversely to the movement plane of said glass sheet (L), so as to be able to engage said edge of the glass sheet (L). Compared to the prior art, the invention offers the advantage of allowing to know the exact position of the glass sheet relative to the spindle of the tool unit that performs the processing of the sheet itself, thanks to a reading of the same position performed directly on the body of the glass sheet.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a device for detecting the position of a glass sheet, movable along a transport direction on a grinding machine.

[0002] The technical field of the present invention is that of grinding machines that process the sides of glass sheets, movable along a transport direction.

[0003] In this type of processing, it is important to know at all times and with accuracy the position of the glass sheet relative to the tool performing the processing (e.g., a grinding spindle, a polishing spindle, a drilling spindle, and the like).

[0004] Currently, there are known toothed belt systems in which the position of the glass sheet is indirectly detected by means of a sensor that reads the pivot angle of the drive shaft of the toothed belt that moves the glass sheet on the processing line, thus providing an indirect reading of the position of the glass sheet.

[0005] The above known solution has the disadvantage of not ensuring accurate reading of the position of the glass sheet, which does not allow for processing operations requiring high processing accuracy.

[0006] Publication WO 2023 / 242883 A1 discloses a unit and a method for detecting the position of a sheet, in particular a glass sheet.SUMMARY OF THE INVENTION

[0007] The main aim of the present invention is to provide a new device for detecting the position of glass sheets on grinding machines which, compared to similar devices of the prior art, offers the possibility of accurately detecting and controlling the position of the glass sheet relative to the tool.

[0008] This and other objects are achieved with the device of claim 1. Preferred embodiments of the invention are set out in the remaining claims.

[0009] Compared to the above-mentioned prior art, the invention offers the advantage of allowing the exact position of the glass sheet to be known relative to the spindle of the tool unit that performs the processing of the sheet itself, thanks to a reading of the same position performed directly on the body of the glass sheet.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] These and other objects, advantages and characteristics will be apparent from the following description of some preferred embodiments of the detection device of the invention, illustrated by way of non-limiting examples in the figures of the attached drawings. In these: Figures 1 and 2 are a partial plan view from above and a partial perspective view, respectively, of a grinding machine equipped with a tool unit and an associated detection device according to the invention; Figures 3 and 4 are a front elevation view of the detection device according to the invention installed on the grinding machine of Figures 1 and 2, shown in two different operating positions; Figure 5 illustrates the operating positions of the detection device according to the invention during the processing stages of a glass sheet with the grinding machine illustrated in Figures 1 and 2; Figures 6 and 7 are a partial plan view from above and a partial perspective view, respectively, of a variant of a grinding machine equipped with a pair of tool units and an associated pair of detection devices according to the invention, Figures 8 and 9 show a front elevation view of the detection devices according to the invention installed on the grinding machine of Figures 6 and 7, represented in two different operating positions. Figures 10a and 10b illustrate the operating positions of the detection devices according to the invention during the processing stages of a glass sheet with the grinding machine illustrated in Figures 6 and 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] With initial reference to Figures 1 and 2 of the drawings, these show a grinding machine, indicated as a whole with the numeral 1, for processing a glass sheet L that is movable along a horizontal transport direction X. In accordance with the prior art, the grinding machine 1 has a bilateral configuration, with two identical sides between which the glass sheet L is advanced, so as to be able to process simultaneously the front corners, in a first stage, and the rear corners, in a second stage, of the glass sheet L as it advances in the transport direction X. However, for simplicity of representation, Figures 1 and 2 show only one side of the grinding machine 1, it being understood that the other side is configured and arranged in a mirror-symmetrical manner with respect to a horizontal central axis of the glass sheet L parallel to the transport direction X.

[0012] Each side of the grinding machine 1 is equipped with a toothed belt conveyor 2 for moving the glass sheet L and a tool unit 3 that can be moved along a direction Y, transverse to the transport direction X of the glass sheet L.

[0013] The tool unit 3 is configured to perform, for example, grinding or polishing of a circular joint at the corners defined between two adjacent sides of glass sheet L. During this process, the tool unit 3 is moved along the direction Y, depending on the position of the glass sheet L along the transport direction X. In order for tool unit 3 to perform the machining correctly, it is important to determine as accurately as possible the position of glass sheet L along the transport direction X, because it is on the basis of this position that the control unit of grinding machine 1 controls the position of tool unit 3 along the direction Y.

[0014] To this end, the invention provides for each tool unit 3 to be associated with a detection device 4 capable of directly detecting the position of the glass sheet L along the transport direction X. The detection device 4, according to the invention, comprises a slider 5 movable along a guide direction C and bearing a pad 6 for contact with an edge of the glass sheet L, an actuator 7 for moving the slider 5 along the guide direction C, and a linear position transducer 8 for detecting the position of the slider 5 along the guide direction C. The linear position transducer 8 consists, for example, of an MTS type encoder from GIVI MISURE.

[0015] As can be seen in more detail in Figures 3 and 4 of the drawings, the actuator 7 is mounted on an adjustable support 9 designed to move slider 5, in a reversible manner, from a first position (Fig. 3) in which the pad 6 is vertically spaced from the movement plane of the glass sheet L, so as not to interfere with the movement thereof, to a second position (Fig. 4) in which the pad is arranged transversely to the movement plane of the glass sheet L, so as to engage a corresponding edge of the glass sheet L. In the illustrated embodiment, the adjustable support 9 is connected in an articulated manner to the frame of the conveyor 2 and is actuated by the stem of an actuator 10 to perform a rotational movement with respect to the aforementioned frame in the direction of the arrows F. The actuator 10 is fixed to a support bracket 11 rigidly connected to the frame of the conveyor 2. Of course, other arrangements are conceivable for imparting a rotational movement to the adjustable support 9. Taking into account in particular that the reading system used in the device of the invention must be disengageable from the glass sheet in order to complete each cycle, this result can also be achieved by means of translations or combinations of rotational and translational movements of the aforementioned adjustable support.

[0016] With reference to Figure 5 of the drawings, the operation of the detection device 4 for detecting the position of the glass sheet L along the transport direction X during processing, for example for polishing the corners of the glass sheet L, will now be described. In the following description, the terms "head" and "tail" of the glass sheet L refer to the front and rear sides of the glass sheet L, respectively, relative to the transport direction X. In all the operating stages described below, the glass sheet L is advanced between the sides of the grinding machine 1 from right to left in the stages illustrated in Figure 5, without any need to stop the movement of the glass sheet L in order to detect its position by means of the detection device 4. In the aforementioned figure, the spindle of the tool unit 3 is represented schematically and denoted by 12.

[0017] In the operating stage A of Fig. 5, the detection device 4 is waiting for the glass sheet L with the slider 5 fully extended to the right and the pad 6 in the lowered position, so that it is arranged transversely to the movement plane of the glass sheet L and can come into contact with the head side of the same.

[0018] In the operating stage B of Fig. 5, the head side of the glass sheet L impacts against the pad 6 of the detection device 4 and begins to push the slider 5 to the left. In this stage, the detection device 4 begins to read the position of the glass sheet L.

[0019] In the operating stage C of Fig. 5, the glass sheet L has reached the end of the reading zone of the detection device 4, which corresponds to the working area of the spindle 12 of the tool unit 3. In this stage, the detection device 4 ends reading the position of glass stage L.

[0020] In the operating stage D of Fig. 5, the detection device 4 retracts the slider 5 completely to the left to distance the pad 6 from the head side of the glass sheet L and thus avoid any contact with the glass sheet L in the subsequent stage of lifting the pad 6.

[0021] In the operating stage E of Fig. 5, the detection device 4 moves the pad 6 to a raised position to move it away from the movement plane of the glass sheet L, so that it does not interfere with the passage of the latter.

[0022] In the operating stage F of Fig. 5, the detection device 4 fully extends the slider 5, leaving the pad 6 in the raised position so as not to interfere with the passage of the glass sheet L.

[0023] In the operating stage G of Fig. 5, the detection device 4 keeps the pad 6 in the raised position while waiting for the passage of the glass sheet L to be completed.

[0024] In the operational stage H of Fig. 5, the passage of glass sheet L is complete. The detection device 4 moves the pad to the lowered position, so that it is positioned transversally to the movement plane of the glass sheet L.

[0025] In the operating stage I of Fig. 5, the detection device 4 retracts the slider 5 to the left to bring the pad 6 into contact with the tail edge of the glass sheet L. In this stage, the detection device 4 begins to read the position of the glass sheet L.

[0026] In the operating stage L of Fig. 5, the glass sheet L has reached the end of the reading zone of the detection device 4, which corresponds to the working area of the spindle 12 of the tool unit 3. In this stage, the detection device 4 ends reading the position of the glass sheet L.

[0027] Finally, in the operating stage M of Fig. 5, the detection device 4 fully extends the slider 5 to the right, leaving the pad 6 in the lowered position, waiting for a new glass sheet.

[0028] From the previous description of the operation of the detection device 4, it can be understood how the working cycle of the spindle 12 of the tool unit 3 is determined by the working cycle of the detection device 4 associated with the tool unit 3. The correlation between the two working cycles is determined by the control unit of the grinding machine 1 executing an electronic cam (e.g. MT Works 2 software from Mitsubishi Electric) that uniquely correlates the position of the spindle 12 of the tool unit 3 along the direction Y with the position of the slider 5 along the guide axis C and, therefore, of the glass sheet L along the transport direction X. Since the position of the glass sheet L is determined directly by the position of the slider 5, the correlation between the position of spindle 12 of the tool unit 3 and the position of the glass sheet L is more accurate than that obtainable with known conventional detection methods, which indirectly determine the position of glass sheet L based on the pivot angle of the drive shaft of the toothed belts that move the glass sheet.

[0029] Furthermore, the presence of a detection device 4 for each tool unit 3 makes it possible to compensate for any squaring errors of the glass sheet L. Each detection device 4 detects the relative position of the spindle 12 with respect to the sides of the glass sheet L near the corner that the spindle itself has to work on.

[0030] Moving on to Figures 6 and 7 of the drawings, these illustrate a variant of the grinding machine 1, adapted to perform a grinding operation and a polishing operation in sequence on the corners of a glass sheet L, which moves along the horizontal transport direction X. In this variant too, the grinding machine 1 has a bilateral configuration, with two identical sides between which the glass sheet L is advanced, so as to be able to process simultaneously the front corners, in a first stage, and the rear corners, in a second stage, of the glass sheet L as it advances in the transport direction X. For simplicity of representation, Figures 6 and 7 illustrate only one side of the grinding machine 1, it being understood that the other side is configured and arranged in a mirror-symmetrical manner with respect to a horizontal central axis of the glass sheet L parallel to the transport direction X.

[0031] The grinding machine 1 is equipped with a pair of tool units 3A and 3B and an associated pair of detection devices according to the invention, indicated by 4A and 4B, respectively, to detect the position of the glass sheet L along the transport direction X. The tool unit 3A is adapted to perform a grinding operation, while the tool unit 3B is adapted to perform a polishing operation on the corners of the glass sheet L. During these operations, each tool unit 3A and 3B is moved individually along the direction Y, depending on the position of the glass sheet L along the transport direction X.

[0032] The detection devices 4A and 4B are identical, but arranged in a mirror-symmetrical manner with respect to a vertical centre plane between the tool units 3A and 3B. Each detection device 4A, 4B comprises a slider 5A, 5B movable along a guide direction C and bearing a pad 6A, 6B for contact with an edge of the glass sheet L, an actuator 7A, 7B for moving the respective slider 5A, 5B along the guide direction C, and a linear position transducer 8A, 8B for detecting the position of the slider 5A, 5B along the guide direction C.

[0033] Each actuator 7A, 7B is mounted on an adjustable support 9A, 9B designed to move the slider 5A, 5B, in a reversible manner, from a first position in which the respective pad 6A, 6B is vertically spaced from the movement plane of the glass sheet L, so as not to interfere with the movement of the latter, to a second position in which the pad 6A, 6B is positioned transversely to the movement plane of the glass sheet L, so as to engage a corresponding edge of the glass sheet L. Each adjustable support 9A, 9B is connected in an articulated manner to the frame of the conveyor 2 and is actuated by the stem of a corresponding actuator 10A, 10B to perform a rotational movement with respect to the aforementioned frame in the direction of the arrows F. The actuators 10A, 10B are fixed to a support bracket 11 rigidly connected to the frame of the conveyor 2.

[0034] With reference to Figs. 10a and 10b of the drawings, the operation of the detection devices 4A, 4B will now be described. In all the operating stages described below, the glass sheet L is advanced between the sides of the grinding machine 1 from right to left (stages A-M of Figure 5). The spindles of the tool units 3A and 3B are shown schematically and denoted by 12A and 12B, respectively. The spindle 12A of the tool unit 3A performs the grinding operation, whereas the spindle 12B of the tool unit 3B performs the polishing operation on the corners of the glass sheet L.

[0035] In the operating stage A of Fig. 10a, the first detection device 4A is waiting for the glass sheet L with the slider 5A fully extended to the right and the pad 6A in the lowered position, so that it is positioned transversally to the movement line of the glass sheet L and can come into contact with the head side of the latter. The second detection device 4B is also waiting for the glass sheet with the slider 5B fully extended to the right and the respective pad 6B in the lowered position.

[0036] In the operating stage B of Fig. 10a, the head side of the glass sheet L impacts the pad 6A of the first detection device 4A and begins to push the slider 5A to the left. In this stage, the first detection device 4A begins to read the position of the glass sheet L. The second detection device 4B keeps the slider 5B fully extended and the respective pad 6B in the lowered position, waiting for the glass sheet L.

[0037] In the operating stage C of Fig. 10a, the glass sheet L has reached the end of the reading zone of the first detection device 4A, which corresponds to the working area of the spindle 12A of the tool unit 3A. At this stage, the first detection device 4A ends reading the position of the glass sheet L. The second detection device 4B keeps the slider 5B fully extended and the respective pad 6B in the lowered position, waiting for the glass sheet L.

[0038] In the operating stage D of Fig. 10a, the first detection device 4A fully extends the slider 5A to the left to distance the respective pad 6A from the head side of the glass sheet L and thus avoid any contact with the glass sheet L in the subsequent stage of lifting the pad 6A. The second detection device 4B keeps the slider 5B fully extended and the respective pad 6B in the lowered position, waiting for the glass sheet L.

[0039] In the operating stage E of Fig. 10a, the first detection device 4A moves the pad 6A to a raised position to move it away from the movement plane of the glass sheet L, so that it does not interfere with the passage of the latter. The second detection device 4B keeps the slider 5B fully extended and the respective pad 6B in the lowered position, waiting for the glass sheet L.

[0040] In the operating stage F of Fig. 10a, the first detection device 4A retracts the slider 5A completely, leaving the pad 6A in the raised position so that it does not interfere with the passage of the glass sheet L. The second detection device 4B keeps the slider 5B fully extended and the respective pad 6B in the lowered position, waiting for the glass sheet L.

[0041] In the operating stage G of Fig. 10a, the head side of the glass sheet L impacts the pad 6B of the second detection device 4B and begins to push the slider 5B to the left. In this stage, the second detection device 4B begins to read the position of the glass sheet L. The first detection device 4A keeps the pad 6A in the raised position so that it does not interfere with the passage of the glass sheet L.

[0042] In the operating stage H of Fig. 10a, the glass sheet L has reached the end of the reading zone of the second detection device 6B, which corresponds to the working area of the spindle 12B of the second tool unit 3B. In this stage, the second detection device 4B ends reading the position of the glass sheet L. The first detection device 4A keeps the pad 6A in the raised position so that it does not interfere with the passage of the glass sheet L.

[0043] In the operating stage I of Fig. 10a, the second detection device 4B retracts the slider 5B completely to the left to distance the respective pad 6B from the head side of the glass sheet L and thus avoid any contact with the glass sheet L in the subsequent stage of lifting the pad 6B. The first detection device 4A keeps the pad 6A in the raised position so that it does not interfere with the passage of the glass sheet L.

[0044] In the operating stage L of Fig. 10a, the second detection device 4B moves the pad 6B to a raised position to move it away from the movement plane of the glass sheet L, so that it does not interfere with the passage of the latter. The first detection device 4A keeps the pad 6A in the raised position, so that it also does not interfere with the passage of the glass sheet L.

[0045] In the operating stage M of Fig. 10a, the first detection device 4A keeps the pad 6A in the raised position while waiting for the passage of the glass sheet L to be completed. The second detection device 4B fully extends the slider 5B and keeps the pad 6B in the raised position so as not to interfere with the passage of the glass sheet L.

[0046] In the operating stage N of Fig. 10b, the first detection device 4A keeps the pad 6A in the raised position while waiting for the passage of the glass sheet L to be completed. The second detection device 4B keeps the pad 6B in the raised position so that it also does not interfere with the passage of glass sheet L.

[0047] In the operating stage O of Fig. 10b, the passage of the glass sheet L is completed and the first detection device 4A moves the pad to the lowered position, so as to place it transversely to the movement plane of the glass sheet L. The second detection device 4B keeps the pad 6B in the raised position so that it does not interfere with the passage of the glass sheet L.

[0048] In the operating stage P of Fig. 10b, the first detection device 4A extends the slider 5A to the left to bring the respective pad 6A into contact with the tail side of the glass sheet L. In this stage, the first detection device 4A begins to read the position of the glass sheet L. The second detection device 4B keeps the pad 6B in the raised position so that it does not interfere with the passage of the glass sheet L.

[0049] In the operating stage Q of Fig. 10b, the glass sheet L has reached the end of the reading zone of the first detection device 4A, which corresponds to the working area of the spindle 12A of the first tool unit 3A. In this stage, the first detection device 4A ends reading the position of the glass sheet L. The second detection device 4B keeps the pad 6B in the raised position so that it does not interfere with the passage of the glass sheet L.

[0050] In the operating stage R of Fig. 10b, the first detection device 4A fully retracts the slider 5A to the right to distance the respective pad 6A from the tail side of the glass sheet L. The second detection device 4B keeps the pad 6B in the raised position so that it does not interfere with the passage of the glass sheet L.

[0051] In the operating stage S of Fig. 10b, the first detection device 4A keeps the slider 5A in the retracted position, waiting for a new glass sheet. The second detection device 4B keeps the pad 6B in the raised position so that the passage of the glass sheet L is completed.

[0052] In the operating stage T of Fig. 10b, the passage of the glass sheet L is completed. The first detection device 4A keeps the slider 5A in the retracted position, waiting for a new glass sheet. The second detection device 4B moves the pad 6B to the lowered position to place it transversely to the movement plane of the glass sheet L.

[0053] In the operating stage U of Fig. 10b, the first detection device 4A keeps the slider 5A in the retracted position, waiting for a new glass sheet. The second detection device 4B retracts the slider 5B to the left to bring the pad 6B into contact with the tail side of the glass sheet L. In this stage, the detection device 4B begins to read the position of the glass sheet L.

[0054] In the operating stage V of Fig. 10b, the glass sheet L has reached the end of the reading zone of the detection device 4B, which corresponds to the working area of the spindle 12B of the tool unit 3B. In this stage, the detection device 4B ends reading the position of the glass sheet L.

[0055] Finally, in the operating stage Z of Fig. 10b, the first detection device 4A keeps the slider 5A in the retracted position while waiting for a new glass sheet. The second detection device 4B fully extends the slider 5B to the right, while the pad 6B is kept in the lowered position while waiting for a new glass sheet.

[0056] From the above, it can be understood how the invention achieves the intended purpose. Although the invention has been described and illustrated in relation to a preferred embodiment, it is clear that it is susceptible to numerous modifications and variations that are within the reach of the skilled an in the art and therefore fall within the scope of the appended claims.

[0057] For example, the pneumatic actuator 7 and the electronic transducer 8 could be replaced by a linear servomotor, which combines the force and measurement parts of the device in the same component.

Claims

1. Detection device (4, 4A, 4B) for detecting the position of a glass sheet (L) movable along a horizontal transport direction (X) on a grinding machine (1), characterised in that it comprises a slider (5, 5A, 5B) movable along a guide direction (C) and bearing a pad (6, 6A, 6B) for contact with an edge of said glass sheet (L), an actuator (7, 7A, 7B) for moving said slider (5, 5A, 5B) along said guide direction (C), and a linear position transducer (8, 8A, 8B) for detecting the position of said slider (5, 5A, 5B) along said guide direction (C), wherein said actuator (7, 7A, 7B) is mounted on an adjustable support (9, 9A, 9B) adapted to move said slider (5, 5A, 5B) reversibly from a first position in which said pad (6, 6A, 6B) is vertically spaced from the movement plane of said glass sheet (L), so as not to interfere with the movement of said glass sheet (L), to a second position in which said pad (6, 6A, 6B) is arranged transversely to the movement plane of said glass sheet (L), so as to be able to engage said edge of the glass sheet (L), wherein said adjustable support (9, 9A, 9B) is adapted to be mounted rotatably on a frame part of said grinding machine (1) and is operatively connected to an actuator (10, 10A, 10B) which controls the rotational movement thereof relative to said frame part of the grinding machine (1).

2. Detection device (4, 4A, 4B) for detecting the position of a glass sheet (L) movable along a horizontal transport direction (X) on a grinding machine (1), characterised in that it comprises a slider (5, 5A, 5B) movable along a guide direction (C) and bearing a pad (6, 6A, 6B) for contact with an edge of said glass sheet (L), and a linear servomotor for moving said slider (5, 5A, 5B) along said guide direction (C), said servomotor being mounted on an adjustable support (9, 9A, 9B) adapted to move said slider (5, 5A, 5B) reversibly from a first position in which said pad (6, 6A, 6B) is vertically spaced from the movement plane of said glass sheet (L), so as not to interfere with the movement of said glass sheet (L), to a second position in which said pad (6, 6A, 6B) is arranged transversely to the movement plane of said glass sheet (L), so as to be able to engage said edge of the glass sheet (L), wherein said adjustable support (9, 9A, 9B) is adapted to be rotatably mounted on a frame part of said grinding machine (1) and is operatively connected to an actuator (10, 10A, 10B) which controls the rotational movement thereof relative to said frame part of the grinding machine (1).

3. Detection device according to claim 1 or 2, characterised in that said actuator (10, 10A, 10B) is adapted to be supported by a bracket (11) rigidly connected to a part of a frame or component of said grinding machine (1).

4. Grinding machine (1) for processing a glass sheet (L) movable along a horizontal transport direction (X), provided with the detection device according to claim 1, said machine comprising a control unit, at least one tool unit (3, 3A, 3B) movable along a direction (Y) transverse to said transport direction (X) of the glass sheet (L) and having a spindle (12, 12A, 12B), said detection device (4, 4A, 4B) being associated with said tool unit (3, 3A, 3B) and adapted to detect the position of the glass sheet (L) along said transport direction (X), characterised in that said detection device (4, 4A, 4B) comprises a slider (5, 5A, 5B) movable along a guide direction (C) and bearing a pad (6, 6A, 6B) for contact with an edge of said glass sheet (L), an actuator (7, 7A, 7B) for moving said slider (5, 5A, 5B) along said guide direction (C) and a linear position transducer (8, 8A, 8B) for detecting the position of said slider (5, 5A, 5B) along said guide direction (C), wherein said actuator (7, 7A, 7B) is mounted on an adjustable support (9, 9A, 9B) adapted to move said slider (5, 5A, 5B) reversibly from a first position in which said pad (6, 6A, 6B) is vertically spaced from the movement plane of said glass sheet (L), so as not to interfere with the movement of said glass sheet (L), to a second position in which said pad (6, 6A, 6B) is arranged transversely to the movement plane of said glass sheet (L), so as to be able to engage said edge of the glass sheet (L).

5. Grinding machine (1) for processing a glass sheet (L) movable along a horizontal transport direction (X), equipped with the detection device according to claim 2, said machine comprising a control unit, at least one tool unit (3, 3A, 3B) movable along a direction (Y) transverse to said transport direction (X) of the glass sheet (L) and having a spindle (12, 12A, 12B), said detection device (4, 4A, 4B) being associated with said tool unit (3, 3A, 3B) and adapted to detect the position of the glass sheet (L) along said transport direction (X), characterised in that said detection device (4, 4A, 4B) comprises a slider (5, 5A, 5B) movable along a guide direction (C) and bearing a pad (6, 6A, 6B) for contact with an edge of said glass sheet (L), and a linear servomotor for moving said slider (5, 5A, 5B) along said guide direction (C), wherein said servomotor is mounted on an adjustable support (9, 9A, 9B) adapted to move said slider (5, 5A, 5B) reversibly from a first position in which said pad (6, 6A, 6B) is vertically spaced from the movement plane of said glass sheet (L), so as not to interfere with the movement of said glass sheet (L), to a second position in which said pad (6, 6A, 6B) is arranged transversely to the movement plane of said glass sheet (L), so as to be able to engage said edge of the glass sheet (L), wherein said adjustable support (9, 9A, 9B) is adapted to be rotatably mounted on a frame part of said grinding machine (1) and is operatively connected to an actuator (10, 10A, 10B) which controls the rotational movement thereof relative to said frame part of the grinding machine (1).

6. Grinding machine according to claim 4 or 5, characterised in that said control unit is configured to correlate the position of the glass sheet (L) along the transport direction (X) with the position of the spindle (12, 12A, 12B) of the tool unit (3, 3A, 3B) along the direction Y.

7. Grinding machine according to claim 6, characterised in that it comprises a plurality of tool units (3A, 3B) and a plurality of detection devices (4A, 4B), wherein each of said detection devices (4A, 4B) is associated with a corresponding tool unit (3A, 3B).

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