DEVICE FOR INSERTING PARTS INTO A GRINDER

Abstract

The invention relates to a device for inserting parts (10) having a cylindrical portion, into a guide rail (105) of a cylindrical grinding machine (100) with grinding wheels (101, 103), comprising: - a base (11) fixed relative to the guide rail (105), - an arm (3), movable in rotation relative to the base (11) between a loading position of a part (10) to be ground, in which its free end is relatively far from the guide rail (105), and an unloading position of the part (10) to be ground, in which its free end is located above the guide rail (105), characterized in that it further comprises a suction gripping head (7), comprising: - a suction mouth (71) connected to a vacuum generator (dP), - two parallel lips (75), bearing against two generatrices of the cylindrical portion of the part (10). Figure for the abridged version: [Fig. 2]

Description

Title of the invention: DEVICE FOR INSERTING PARTS INTO A GRINDER technical field

[0001] The present invention relates to the general field of devices for supplying machine tools with parts for machining at high rates.

[0002] The invention relates more specifically to the insertion of parts into a grinding machine, and in particular of parts with a circular cross-section, at least on a segment of their length.

[0003] Prior techniques

[0004] Grinding machines are machine tools used to improve the surfaces and dimensions of machined parts, in particular by means of grinding wheels.

[0005] Cylindrical grinding machines use circular grinding wheels, with a working wheel and a moving drive wheel, to grind cylindrical portions of workpieces. The grinding wheels clamp the workpiece placed between them, so as to polish and grind the workpiece.

[0006] Such parts may, for example, be dental bur shafts, comprising a tubular base supporting an abrasive machined head. Alternatively, other relevant parts may be vehicle steering rods. The mass and dimensions of these parts are therefore variable.

[0007] Placing the workpiece between the grinding wheels is a delicate operation, made dangerous by the proximity of the wheels, and generally limits the grinding machine's speed. This operation is usually performed manually, by placing the workpiece in a guide rail located between the grinding wheels. The guide rail's movement is controlled by a servo mechanism to compensate for wheel wear, thus ensuring the stability of the grinding operation on a large number of workpieces.

[0008] The small space between the grinding wheels makes it dangerous to place the workpiece in the guide rail by hand, and prevents the use of a gripper-type robot that would laterally pinch the workpiece to be ground.

[0009] In particular, parts smaller than one centimeter in diameter and / or length can be difficult to handle and place precisely on a ruler.

[0010] There is therefore a need for a device to insert parts between grinding wheels, in particular cylindrical grinding wheels, in a precise and repeatable manner on a ruler in the narrow and dangerous space between the grinding wheels. Description of the invention

[0011] To meet this need, the invention proposes a device for inserting parts having a cylindrical portion into a cylindrical grinding wheel guide, comprising: - a fixed base relative to the ruler, - an arm, movable in rotation relative to the base between a position of loading a part to be ground, in which its free end is relatively far from the ruler, and a position of unloading the part to be ground, in which its free end is located above the ruler.

[0012] The device is characterized in that it further comprises a suction-gripping head, comprising: - a suction opening connected to a vacuum generator configured to allow the part to be gripped by suction in the loading position by generating a vacuum, and the part to be released in the unloading position by stopping the vacuum, - two parallel lips, between which the depression is generated, coming into contact, when a part is taken by the gripping head, against two generatrices of the cylindrical portion of the part.

[0013] By using suction gripping, the device avoids the use of a clamp with lateral gripping elements which increase its width, making it more complicated to insert the part onto the ruler between the grinding wheels.

[0014] The device according to the invention may have one or more of the following characteristics, alone or in combination.

[0015] The arm can be set in motion by a brushless motor, configured to brake the arm by generator operation when approaching the loading position.

[0016] The gripping head can in particular be connected to the vacuum generator by a pneumatic line, comprising a segment passing through the axis of rotation of the arm.

[0017] The device may include an adjustable stop screw, forming a stop for the part in the axial direction of its cylindrical portion.

[0018] The base may include adjustment screws to adjust the relative position of the gripping head with respect to the ruler.

[0019] The lips can in particular be the lower border of two parallel vertical walls.

[0020] The vacuum generator can be a reversible pump, configured to also generate an overpressure when the arm is in the unloading position to eject the part onto the strip.

[0021] The base may include a tip for aligning a multi-axis supply robot, configured to deposit parts onto the gripping head in the loading position.

[0022] The device may further include a supply robot, configured to take parts from a supply, and place them on the gripping head.

[0023] Said supply robot may have a suction gripping head comprising: - a suction opening connected to a vacuum generator, configured to allow the part to be gripped by suction, and released by stopping the vacuum, - two lips between which the depression is generated, coming into contact, when a part is taken by the robot's gripping head, against two generators of the cylindrical portion of the part. Brief description of the figures

[0024] Other advantages and features of the invention will become apparent from the following description of the accompanying figures, among which:

[0025] [Fig-1] is a schematic representation of a cylindrical grinder in which The parts can be deposited by the device according to the invention.

[0026] [Fig.2] is a schematic perspective representation in three-quarter front view of a loading device according to an embodiment of the invention, with the arm in the unloading position,

[0027] [Fig.3] is a schematic perspective representation in three-quarter front view of the loading device [Fig.2], with the arm in the loading position,

[0028] [Fig.4] is a schematic three-quarter perspective representation rear of the loading device of [Fig. 2] and 3, with the arm in the loading position,

[0029] [Fig.5] is a cross-sectional view of the gripping head of the device according to an embodiment of the invention,

[0030] [Fig.6] is a schematic side view of the gripping head of [Fig.5],

[0031] [Fig.7] is a schematic representation of a device according to another mode of the realization with the arm shown in both loading and unloading positions,

[0032] [Fig.8] is a schematic representation of a device according to a mode of implementation including a supply robot.

[0033] The examples are given by way of illustration and are not intended to be limiting. Other embodiments of the invention can easily be obtained by variations and combinations of the embodiments shown. The dimensions and proportions illustrated in the figures may differ from reality and may have been adapted to facilitate understanding of the invention. Detailed description

[0034] Fig. 1 is a schematic representation of a cylindrical grinding machine with grinding wheels.

[0035] The grinding machine 100 has two grinding wheels 101, 103, (which are rotated to work).

[0036] During grinding, the drive wheel 103 performs a reciprocating translational movement. The working wheel 101 remains fixed.

[0037] During grinding, the part 10 is carried by a guide rail 105. When the part 10 is on the guide rail 105, it is in contact with the working wheel 101. During grinding, the drive wheel 103 moves into contact with the part 10 and compresses the part 10 between the two wheels 101, 103.

[0038] Part 10 has a cylindrical portion represented by its circular section placed on the strip 105.

[0039] The grinding wheels 101 and 103 are set in rotation in opposite directions relative to each other by motors (not shown).

[0040] When the cylindrical portion of the part 10 is taken between the two rotating grinding wheels 101, 103, the part 10 is driven in rotation by friction by the drive grinding wheel 103.

[0041] The part 10 rubs between the grinding wheels and it then undergoes abrasion by friction against the two grinding wheels 101, 103.

[0042] The ruler 105 is in particular movable on a large number of rectifications to follow the wear of the grinding wheels 101, 103 according to formulas known to the Man skilled in the art.

[0043] Figures 2, 3 and 4 show an insertion device 1 for parts 10 in such a grinder 100 according to an embodiment of the invention, for depositing the part 10 in the ruler 105 of the cylindrical grinder 100 with grinding wheels 101, 103.

[0044] The insertion device 1 comprises a movable arm 3 rotating about an axis A, driven by a motor 5 protected by a cover 51 in figures 2 and 3 and visible in [Fig.4].

[0045] The motor 5 is advantageously a "brushless" type motor, firstly because of their lower wear, and secondly because of their operation in generator mode allowing active braking.

[0046] In particular, the motor 5 is configured to brake the arm 3 as it approaches the unloading position, in order to avoid an excessively hard stop which would eject the part 10 in an uncontrolled manner.

[0047] As an alternative or in addition, the device 1 may include shock absorbers which absorb shocks and decelerations at the extreme loading and / or unloading positions during the tilting of the arm 3.

[0048] The arm 3 is shown in [Fig.2] in an extreme position for unloading the part 10, in which the free end of the arm 3 is located above the strip 105 (not shown) to unload the part 10 onto said strip 105.

[0049] In figures 3 and 4, the arm 3 is shown in the extreme position for loading the part 10, in which its free end is relatively far from the ruler 105 (not shown) to allow the part 10 to be loaded onto the device 1 outside the space between the grinding wheels 101, 103.

[0050] At the free end of the arm 3 is located a gripping head 7 which serves to hold the part 10 and release it in a controlled manner onto the strip 105. The gripping head 7 is a suction gripping head, connected via a pneumatic line 9 to a vacuum generator, creating suction, for example a vacuum pump. The gripping head 7 is discussed in more detail with reference to Figures 5 and 6 below.

[0051] The pneumatic line 9 passes in particular through the axis of rotation A of the arm 3, with a segment aligned with said axis of rotation A and a freely rotating connection 91 to the vacuum generator so that the deformations of the pneumatic line 9 during the tilting of the arm 3 between the loading and unloading positions are minimal.

[0052] The arm 3 and the motor 5 are notably supported by a base 11 fixed relative to the rail 105, whose movement it follows. The position of the base 11 relative to the rail 105 is adjustable by means of adjusting screws 13, allowing adjustment and centering of the unloading position relative to the rail 105 to optimize the placement of the part 10 onto the rail 105.

[0053] The adjustment of the longitudinal position of the part 10 on the gripping head 7 in the loading position is ensured by an adjustable stop screw 15, against which one end of the part 10 comes to rest when it is placed on the gripping head 7.

[0054] To enable automated loading, the device 1 may include a loading robot (see [Fig. 8]). To allow the alignment of this robot, the device 1 shown is provided with a conical tip 17 for aligning said robot, so that it can follow the movements of the base 11 and the guide 105.

[0055] Figures 5 and 6 illustrate the gripping head 7 in more detail. [Fig.5] is a cross-sectional view in the transverse plane of the gripping head 7, and [Fig.6] is a side view of the gripping head 7.

[0056] In [Fig.5] we see that the gripping head 7 has a suction mouth 71, shown here circular, connected to the pneumatic line 9.

[0057] The gripping head 7 also includes two parallel lateral walls 73, having at their lower end two straight lips 75, which, when a part 10 is gripped, come to rest against two generatrices of the cylindrical portion of the part 10.

[0058] The side walls 73 contribute to the fineness of the gripping head 7, so that it can easily be inserted into the space between the grinding wheels 101, 103 of the grinder 100.

[0059] The lips 75 may, in particular, be coated with a polymer material to reduce scratches on the part 10 if the gripping head 7 is made of hard metal. Alternatively, the gripping head 7 may be made entirely of polymer material, in particular by three-dimensional printing.

[0060] The pneumatic line 9 is connected to a vacuum pump dP, which creates a vacuum to hold the part 10, and stops generating the vacuum when the arm 3 is in the unloading position, in order to release the part 10 in a controlled manner onto the strip 105.

[0061] In particular, the vacuum pump can be reversible, and generate an overpressure on occasion to release the part 10 when the arm 3 is in the unloading position.

[0062] Figure 7 illustrates the loading and unloading of part 10 by means of the Device 1. The arm of device 1 is shown in the two extreme loading and unloading positions.

[0063] In the loading position (right in [Fig. 7]), the gripping head 7 is oriented with its lips 75 facing upwards. The part 10 is loaded onto said gripping head 7, for example manually by an operator.

[0064] Before the arm 3 tilts, the pump dP generates a vacuum which secures the part 10 and the gripping head 7. The arm 3 then tilts towards the unloading position by pivoting around the axis A, carrying the part 10 with it.

[0065] In the unloading position (left in [Fig.7]), the pump dP stops generating the vacuum, which separates the gripping head 7 and the part 10, possibly generating momentarily an overpressure.

[0066] The part 10 then falls onto the rail 105 just below the gripping head 7 in the unloading position. Then, the arm 3, without the loaded part 10, returns to the loading position by tilting in the opposite direction.

[0067] According to one embodiment, the arm 3 and the gripping head 7 are used to remove the part 10 once its grinding is complete. To do this, the arm 3 tilts into the unloading position opposite the part 10 located on the strip 105, and the pump dP is then activated to generate suction, so that the gripping head 7 draws in the part 10.

[0068] By tilting the arm 3 again, towards the loading position, the part 10 is made accessible to the operator.

[0069] Figure 8 illustrates an embodiment of device 1 further comprising a loading robot 2, in particular a six-axis robot.

[0070] The loading robot 2 is in the form of an arm configured to grasp parts 10 to be ground, coming from a supply, for example an output from a milling lathe type machine tool producing the parts 10.

[0071] In particular, the supply can be in the form of a conveyor belt with a vibrating portion to separate the parts 10, the robot 2 grasping the parts one by one on the conveyor belt, with the assistance of a system for visualizing the parts on the conveyor belt.

[0072] In particular, the robot 2 may have a suction gripping head 7 similar or identical to the gripping head 7 at the end of the arm 3, comprising lips and a suction opening.

[0073] Alternatively, the robot 2 can be equipped with a gripper in place of the suction gripping head 7. The robot 2 can also be used to unload the ground part 10 from the gripping head 7 of the arm 3.

[0074] The device 1 according to the invention allows the part 10 of the ruler 105 of a grinder 105 to be loaded and possibly unloaded in the space between the grinding wheels 101, 103, a narrow and dangerous space.

[0075] In particular, the rate can be increased compared to manual loading, since an operator only has to load the part 10 onto the gripping head 7 in the loading position, therefore out of the space between the grinding wheels 101, 103. The risks of injury to operators are then reduced.

[0076] Alternatively, the loading and unloading of part 10 can be automated by means of robots 2, which can further increase the grinding rate.

Claims

Demands

1. A device for inserting workpieces (10) having a cylindrical portion into a guide rail (105) of a cylindrical grinding machine (100) with grinding wheels (101, 103), comprising: - a base (11) fixed relative to the guide rail (105), - an arm (3) rotatably movable relative to the base (11) between a workpiece loading position (10) to be ground, in which its free end is relatively far from the guide rail (105), and a workpiece unloading position (10) to be ground, in which its free end is located above the guide rail (105), characterized in that it further comprises a suction gripping head (7), comprising: - a suction inlet (71) connected to a vacuum generator (dP), configured to allow the workpiece (10) to be gripped by suction in the loading position by generating a vacuum, and the release of the workpiece (10) in the unloading position by stopping the depression, - two parallel lips (75),between which the depression is generated, coming into contact, when a part (10) is gripped by the gripping head (7), against two generatrices of the cylindrical portion of the part (10).

2. Device according to claim 1, characterized in that the arm (3) is set in motion by a brushless motor (5), configured to brake by generator operation the arm (3) as it approaches the loading position.

3. Device according to claim 1 or 2, characterized in that the gripping head (7) is connected to the vacuum generator (dP) by a pneumatic line (9), comprising a segment passing through the axis of rotation (A) of the arm (3).

4. Device according to any one of the preceding claims, characterized in that it comprises an adjustable stop screw (15), forming a stop for the part (10) in the axial direction of its cylindrical portion.

5. Device according to any one of the preceding claims, characterized in that the base (11) has adjustment screws (13) for adjusting the relative position of the gripping head (7) with respect to the ruler (105).

6. Device according to any one of the preceding claims, characterized in that the lips (75) are the lower edge of two parallel vertical walls (73).

7. Device according to any one of the preceding claims, characterized in that the vacuum generator (dP) is a reversible pump, configured to also generate an overpressure when the arm (3) is in the unloading position to eject the part (10) onto the strip (105).

8. Device according to any one of the preceding claims, characterized in that the base (11) has a tip (17) for the alignment of a multi-axis supply robot (2), configured to deposit parts (10) onto the gripping head (7) in the loading position.

9. Device according to any one of the preceding claims, characterized in that it further comprises a supply robot (2), configured to take parts (10) from a supply, and place them on the gripping head (7).

10. Device according to the preceding claim, characterized in that the supply robot has a suction gripping head (7), comprising: - a suction mouth connected to a vacuum generator, configured to allow the part (10) to be grasped by suction, and the part (10) to be released by stopping the vacuum, - two lips between which the vacuum is generated, which come into contact, when a part (10) is taken by the gripping head (7) of the robot (2), with two generatrices of the cylindrical portion of the part (10).