drilling device with disengagement of the feed at the end of retraction

Abstract

Drilling device comprising a housing housing: - a motor; - a drilling spindle movable in rotation and / or in translation along a longitudinal axis; - a transmission comprising: - a first pinion linked in rotation with said spindle and movable in translation along said spindle along said longitudinal axis; - a second pinion linked to said spindle by a helical connection along said longitudinal axis; - a third pinion, meshing with said first pinion, and capable of being driven in rotation by said motor; - a fourth pinion, meshing with said second pinion, movable between: - an engaged position in which it is linked in rotation with said third gear, the rotational driving of said third pinion by said motor inducing deployment of said spindle over a predetermined deployment stroke;- a stationary position in which it is linked in rotation with said casing and it is free in rotation with respect to said third pinion, a rotation of said third pinion by said motor inducing a retraction of said spindle following a predetermined retraction stroke, said fourth pinion being able to take an intermediate position in which it is free in rotation with respect to said casing and said third pinion in such a way that it does not exert substantially any torque on said second pinion so that a rotational drive of said third pinion by said motor induces a rotation of said second pinion at the same rotational frequency as that of said spindle. Fig. 1;

Description

Title of the invention: drilling device with disengagement of the feed at the end of retraction 1. Field of the invention

[0001] The field of the invention is that of drilling devices. 2. Prior art

[0002] Drilling devices, also called drills, are commonly used in particular in various industrial sectors, such as aeronautics, to carry out various tasks. In this sector, so-called automatic feed drills are used in particular, i.e. drills whose drilling spindle (or output spindle), which carries a cutting tool, is driven simultaneously in translation and in rotation about its longitudinal axis.

[0003] Patent documents FR-A1-2 881 366 and FR-A1-2 918 592 describe, for example, such drills.

[0004] With reference to [Fig.l], a drill of this type typically comprises:

[0005] - a grooved and threaded output pin 10;

[0006] - a pneumatic motor (not shown) provided with a rotor R and connected to a valve compressed air supply;

[0007] - a transmission T capable of transforming a rotational movement of the rotor R into a rotational and / or translational movement of the output spindle 10 along the same axis, i.e. its longitudinal axis.

[0008] This transmission T includes:

[0009] - a first pinion 11 coaxial with the spindle 10 and provided with internal splines cooperating with the external splines of spindle 10;

[0010] - a second pinion 12 coaxial with the spindle 10 and provided with an internal thread cooperating with the thread of spindle 10;

[0011] - a third pinion 13 with an axis parallel to the spindle 10, meshing with the first pinion 11 following a first transmission ratio and driven in rotation by the drill motor via a pair of bevel gears 15 and / or one or more epicyclic gear trains (not shown);

[0012] - a fourth pinion 14 with an axis parallel to the spindle 10, meshing with the second pinion 12 following a second transmission ratio different from the first ratio.

[0013] The fourth pinion 14 comprises first ogive-shaped dogs 140 capable of cooperating with clutch housings 130 of complementary shape arranged on the third pinion 13 in such a way that when the dogs 140 are housed in the clutch housings 130, the fourth pinion 14 and the third pinion 13 are rotationally linked. As will be described in more detail later, the ogive shape of the first dogs makes them suitable for disengaging the rotational linkage when the fourth and third pinions have begun to move apart from each other.

[0014] The fourth pinion 14 also comprises second dogs 141 of complementary shape to immobilizing dogs 17 fixed relative to the casing C of the drill.

[0015] The fourth pinion 14 is integral in translation with the rod 160 of the piston 161 and free in rotation relative to the latter. This rod 160 is movable in translation along the axis of rotation of the fourth pinion in a chamber 162 of a monostable cylinder 16 so as to be able to take:

[0016] - an engaged position in which the first dogs 140 are housed in the clutch housings 130 and the second dogs 141 do not cooperate with the immobilizing dogs 17 so that the fourth pinion 14 is linked in rotation with the third pinion 13 and movable in rotation relative to the casing C, and

[0017] - an immobilized position in which the first dogs 140 do not cooperate with the clutch housings 130 and the second dogs 141 cooperate with the immobilizing dogs 17 so that the fourth pinion 14 is stationary in rotation relative to the casing C and movable in rotation relative to the third pinion 13.

[0018] To move the fourth pinion 14 from its engaged position to its immobilized position, the side of the chamber 162 of the cylinder 16, facing the fourth pinion 14, is supplied with compressed air. The fourth pinion 14 then moves away from the third pinion 13 against the effect of the spring 163.

[0019] To move the fourth pinion 14 from its immobilized position to its engaged position, the chamber 162 of the cylinder 16 is vented by means of a distributor (not shown) so as to bring the fourth pinion 14 closer to the third pinion 13 under the effect of the spring 163.

[0020] The spindle 10 is provided with an end-of-deployment stop 18 capable of coming to bear on an end-of-deployment stopper fixed in translation (here the first pinion 11) relative to the casing, and with an end-of-retraction stop 19 capable of coming to bear on an end-of-retraction stopper (here the second pinion) fixed relative to the casing.

[0021] This type of drill can also be used to make holes with or without a countersink at the hole entrance. Such a countersink is intended to receive a countersunk head rivet whose surface must be flush with the drilled surface. This assumes control of the drilled depth.

[0022] When starting the drill to carry out a drilling operation with or without countersinking, the end of retraction stop 19 is in contact with the end of retraction stop traction (i.e. the second pinion 12) so that the spindle 10 is completely retracted.

[0023] The fourth pinion 14 is in the engaged position in which it is rotatably connected to the third pinion 13.

[0024] The motor is powered in the working direction (i.e. drilling) in such a way that the third pinion 13 is driven in rotation. The fourth pinion 14, which is linked in rotation with the third pinion 13, rotates at the same speed.

[0025] The first pinion 11 is driven in rotation by the third pinion 13 so that the spindle 10 is driven in rotation along its longitudinal axis.

[0026] The second pinion 12 is driven in rotation by the fourth pinion 14.

[0027] The reduction ratio between the first 11 and the third pinion 12 is different from the reduction ratio between the second pinion 12 and the fourth pinion 14. Thus, taking into account the helical connection between the second pinion 12 and the spindle 10, the spindle 10 is driven in translation along its axis and deploys outside the casing until the end of deployment stop 18 is in abutment against the end of deployment stop (i.e. of the first pinion 11).

[0028] When the deployment end stop 18 is in abutment against the deployment end stop, the deployment of the spindle 10 is stopped so that the second pinion 12 is forced to rotate at the same rotation frequency as that of the spindle 10 and that of the first pinion 11. The third 13 and the fourth 14 pinions therefore tend to rotate at different speeds due to the difference between the reduction ratios mentioned above. Thus, given the ogive shape of the first dogs 140 of the fourth pinion 14, these dogs 140 tend to come out of the clutch housings 130 of the third pinion 13 so that the fourth pinion 14 moves away from the third pinion 13 towards its immobilized position.

[0029] This relative distance of the fourth pinion 14 from the third pinion 13 actuates the distributor (not shown) which supplies the side oriented towards the fourth pinion 14 of the chamber 162 of the jack 16. As a result, the jack 16 drives, against the effect of the spring 163, the fourth pinion 14 into its immobilized position in which it is immobile in rotation relative to the casing without being linked in rotation to the third pinion 13.

[0030] Given that the fourth pinion 14 is immobilized in rotation, the second pinion 12 is also immobilized in rotation relative to the casing. Thus, the spindle 10, which continues to be driven in rotation by the third 13 and the first 11 pinions, moves in translation along its axis in the direction of retraction inside the casing.

[0031] The pitch of the threaded area of ​​the spindle 10 and the difference between the reduction ratios mentioned above lead to the fact that when the fourth pinion 14 is immobilized, the spindle 10 retracts at an appropriate speed, and when the fourth gear 14 is engaged with the third gear 13 the feed per revolution of spindle 10 is in accordance with an appropriate value. This transmission principle is known in the state of the art and will not be described in further detail.

[0032] The retraction of the spindle 10 is carried out until the end of retraction stop 19 is in contact with the end of retraction stopper.

[0033] When the end of retraction stop 19 is in contact with the end of retraction stopper, it acts on a distributor allowing the chamber of the cylinder 16 to be vented and the motor supply valve to be closed.

[0034] The chamber 162 is no longer pressurized so that the piston 161 moves under the effect of the spring 163. The piston 161 thus drives the fourth pinion 14 into its engaged position in which the first dogs 140 are housed in the clutch housings 130 so that the fourth pinion 14 is again linked in rotation with the third pinion 13.

[0035] Although the power supply to the motor is cut off, the rotor of the motor can continue to rotate in the working direction under the effect of its inertia. This is particularly the case for high-speed motors, for example of the order of 60,000 revolutions per minute, and having little internal friction. Thus, since the fourth pinion 14 is in its engaged position with the third pinion 13, the spindle 10 is again driven in rotation and translation along its axis in the direction of deployment.

[0036] Thus, when the kinetic energy of the motor rotor is completely consumed and the rotor finally stops rotating, the end of retraction stop 19 is no longer pressing against the end of retraction stopper and the pin 10 is slightly deployed outside the casing.

[0037] At the end of a drilling operation comprising the phases of drilling, possibly milling and then retraction of the spindle, it is logically sought that at the moment when the rotor of the motor stops rotating, the spindle is still in the same position corresponding to the start of a drilling cycle, i.e. the position defined by the support of the end of retraction stop against the end of retraction stop.

[0038] However, given that at the end of retraction, the fourth pinion 14 is in the engaged position with the third pinion 13 and that the rotor of the motor continues to rotate, after its power supply is cut off, under the effect of the kinetic energy that it has accumulated during retraction, the spindle 10 tends to move forward again and to deploy a little outside the casing after retraction.

[0039] Thus, when the rotor stops rotating, the spindle may be in a partially extended longitudinal position rather than in the position defined by the end of retraction stop.

[0040] As a result, the remaining deployment stroke that the spindle can travel in the next drilling cycle is not total and may vary from one drilling cycle to another.

[0041] This can have a negative impact on the accuracy of the drilling, in particular on the accuracy of their depth and, where appropriate, on the quality of the countersinking.

[0042] There is therefore a need to improve this type of drill. 3. Objectives of the invention

[0043] The invention aims in particular to provide an effective solution to at least some of these different problems.

[0044] In particular, according to at least one embodiment, an objective of the invention is to make automatic feed drills more reliable.

[0045] In particular, the invention aims, according to at least one embodiment, to provide such a drill whose spindle deployment stroke at the start of drilling operations is repeatable.

[0046] Another objective of the invention is, according to at least one embodiment, to provide such a drill whose drilling spindle stops at the end of retraction, at the same position.

[0047] Another objective of the invention is to provide, in at least one embodiment, such a technique which is simple and / or robust and / or economical. 4. Presentation of the invention

[0048] For this, the invention proposes a drilling device comprising a casing housing:

[0049] - a motor comprising a rotor capable of rotating in a working direction;

[0050] - a transmission;

[0051] - a drilling spindle capable of being driven in rotation and / or in translation along a longitudinal axis of said spindle via said motor and said transmission;

[0052] said transmission comprising:

[0053] - a first pinion linked in rotation with said spindle and mounted mobile in translation along said spindle following said longitudinal axis of said spindle;

[0054] - a second pinion linked to said spindle by a helical connection along said axis longitudinal of said spindle;

[0055] - a third pinion, meshing with said first pinion, and capable of being driven in rotation by said motor;

[0056] - a fourth pinion, meshing with said second pinion, said fourth pinion being mobile between:

[0057] - an engaged position in which it is rotationally linked with said third gearing by connecting means, the rotational drive of said third pinion by said motor in said working direction inducing deployment of said spindle on a predetermined deployment course;

[0058] - an immobilized position in which it is rotationally linked with said casing and it is free to rotate relative to said third pinion, a rotation of said third pinion by said motor in said working direction inducing a retraction of said spindle following a predetermined retraction stroke,

[0059] According to the invention, said fourth pinion is capable of taking an intermediate position in which it is free to rotate relative to said casing and said third pinion in such a way that it exerts substantially no torque on said second pinion so that rotational driving of said third pinion by said motor induces rotation of said second pinion at the same rotation frequency as that of said spindle.

[0060] Thus, the invention provides a technical solution making it possible to ensure that, after the spindle has been retracted, it cannot be moved forward again while the rotor of the motor continues to rotate under the effect of the dissipation of the kinetic energy that it has accumulated.

[0061] The invention thus makes it possible to guarantee that, at the end of the spindle retraction phase of each drilling cycle, the spindle is systematically stopped in translation in the same position.

[0062] Therefore, at the start of each drilling cycle, the available spindle deployment stroke is always the same.

[0063] This improves the quality of the drilling in terms of depth and, where appropriate, in terms of the execution of the countersinking.

[0064] According to a possible characteristic, a drilling device according to the invention comprises means for holding said fourth pinion in said intermediate position at the end of said retraction stroke of said spindle.

[0065] According to a possible characteristic, a drilling device according to the invention comprises:

[0066] - an end of deployment stop carried by said pin and capable of coming into support against an end-of-deployment stopper, said end-of-deployment stopper being axially fixed relative to said casing;

[0067] - a retraction end stop carried by said pin and capable of coming into support against a retraction end stop, said retraction end stop being axially fixed relative to said casing;

[0068] - a first cylinder comprising a rod capable of axially moving said fourth pinion between said engaged and immobilized positions,

[0069] - means for controlling said first cylinder configured to:

[0070] - moving said rod in a first direction inducing a movement of said fourth pinion from said engaged position to said immobilized position when said deployment end stop touches said deployment end stop;

[0071] - moving said rod in a second direction inducing a movement of said fourth pinion from said immobilized position to said engaged position when said end of retraction stop touches said end of retraction stopper.

[0072] According to a possible characteristic, said first cylinder is a single-acting type cylinder comprising a chamber in which said first rod is capable of sliding against the effect of elastic return means, said control means being capable of:

[0073] - supplying compressed air to said chamber of said cylinder to induce said de placement in said first direction, said control means of said first cylinder acting on said distribution means to trigger said supply when said end of deployment stop touches said end of deployment stop;

[0074] - venting said chamber, when said end of retraction stop touches said end of retraction stopper, so as to induce said movement in said second direction under the effect of a relaxation of said elastic return means of said first cylinder.

[0075] According to a possible characteristic, said means for holding said fourth pinion in said intermediate position comprise:

[0076] - a shoulder provided on said rod of said first cylinder, said shoulder separating two areas of said stem:

[0077] - a first zone having a first diameter extending on the side of said piston of said first cylinder;

[0078] - a second zone having a second diameter extending on the side of said fourth pinion, said second diameter being less than said first diameter;

[0079] - a latch which can occupy:

[0080] - a blocking position in which said shoulder can come into contact with said latch when said rod is moved in said second direction, the fourth pinion occupying said intermediate position when said shoulder is in contact with said latch;

[0081] - a passing position in which said shoulder can freely cross said latch when said rod is moved in said second direction.

[0082] According to a possible characteristic, said latch is:

[0083] - linked in rotation at one of its ends around an axis parallel to said rod of said first cylinder and fixed in said casing;

[0084] - connected at the other of its ends to a second single-acting cylinder, said device comprising means for controlling said second cylinder configured to activate said second cylinder in order to move said latch towards one or other of the blocking or passing positions.

[0085] According to a possible characteristic, said fourth pinion comprises first dogs and said casing comprises second dogs, said first and second dogs being configured to connect in rotation said fourth pinion and said casing in said immobilized position, said second dogs being mounted mobile in rotation along the axis of rotation of said fourth pinion over a predetermined angular range against the effect of third elastic return means.

[0086] The invention also covers a method of drilling an element during a drilling operation by means of a drilling device according to any one of the above variants, said method comprising a step of positioning and holding said fourth pinion in said intermediate position in which it is free to rotate relative to said housing and said third pinion in such a way that it exerts substantially no torque on said second pinion so that rotational driving of said third pinion by said motor induces rotation of said second pinion at the same rotation frequency as that of said spindle.

[0087] According to a possible variant, a method according to the invention comprises, following contact between said end-of-deployment stop and said end-of-deployment stopper:

[0088] - a step of retracting said pin until said end stop traction is in contact with said end of retraction stopper;

[0089] - a step of stopping the power supply to said motor;

[0090] - said step of moving and holding said fourth pinion in said intermediate position;

[0091] - a residual rotation step of said rotor, under the effect of its kinetic energy, until said rotor is immobilized after said kinetic energy is absorbed, said rotor rotating, during said residual rotation step, said third pinion, and said fourth pinion exerting during this rotation substantially no torque on said second pinion so that said spindle is immobile in translation.

[0092] According to a possible variant, a method according to the invention comprises:

[0093] - a step of starting said drilling device in order to carry out said drilling operation,

[0094] - a step of positioning said fourth pinion in said engaged position at the end of said device start-up step and prior to carrying out said drilling operation. 5. Description of figures

[0095] Other characteristics and advantages of the invention will appear on reading the following description of particular embodiments, given as a simple illustrative and non-limiting example, and the appended drawings among which:

[0096] [Fig-1] [Fig. 1] illustrates a longitudinal and partial sectional view of a drill according to the prior art;

[0097] [Fig.2] [Fig.2] illustrates a partial perspective view of the interior of a drill according to a first embodiment of the invention;

[0098] [Fig.3] [Fig.3] illustrates a longitudinal and partial sectional view of the drill of [Fig.2] whose spindle is fully retracted with the fourth pinion in the intermediate position;

[0099] [Fig.4] [Fig.4] illustrates a longitudinal and partial sectional view of the drill of [Fig.2] with the spindle being deployed and the fourth pinion in the engaged position;

[0100] [Fig.5] [Fig.5] illustrates a longitudinal and partial sectional view of the drill of [Fig.2] with the spindle fully extended and the fourth pinion in the immobilized position;

[0101] [Fig.6] [Fig.6] illustrates a longitudinal and partial sectional view of the drill of [Fig.2] with the spindle being retracted and the fourth pinion in the immobilized position;

[0102] [Fig.7] [Fig.7] illustrates a longitudinal and partial sectional view of the drill of [Fig.2] with the spindle close to full retraction and the fourth pinion in an intermediate position;

[0103] [Fig.8][Fig.9] Figures 8 and 9 illustrate cross-sectional and partial views of the drill in [Fig.2] with the latch in the unlocked position;

[0104] [Fig. 10][Fig. 11] Figures 10 and 11 illustrate cross-sectional and partial views of the drill of [Fig.2] whose distributor is in a vented state

[0105] [Fig.l2][Fig.l3] Figures 12 and 13 illustrate cross-sectional views of the drill of [Fig.2] with the latch in the locked position;

[0106] [Fig.l4][Fig.l5] Figures 14 and 15 illustrate cross-sectional views of the drill of [Fig.2] with the distributor in the vented condition;

[0107] [Fig. 16] [Fig. 16] illustrates a partial longitudinal sectional view of the interior of a drill according to a second embodiment of the invention provided with a vibrator;

[0108] [Fig. 17] [Fig. 17] illustrates a detail view of [Fig. 16];

[0109] [Fig. 18] [Fig. 18] illustrates a flowchart of the operation of a device according to the invention.

[0110] 6. Description of particular embodiments 6.1. Architecture

[0111] An example of an embodiment of a drill according to the invention is presented in relation to figures 2 to 15.

[0112] As shown in these figures, such a drill conventionally comprises a casing 20 outside of which a spindle 10 is capable of being deployed. This spindle is capable of carrying a drill bit at its end close to the end of retraction stop. This drill bit is coaxial with the spindle and rotationally connected with respect to the latter.

[0113] The spindle 10 comprises longitudinal grooves 101 and is threaded 102 over its entire length.

[0114] Pin 10 is provided with: - an end-of-deployment stop 18 capable of coming to bear against an end-of-deployment stop fixed in translation relative to the casing along the axis of the spindle, in this case said stop is constituted by the end of the first pinion 11 for the devices shown in Figures 2 to 15, and - a retraction end stop 19 capable of coming to bear on a retraction end stop fixed in translation relative to the casing along the axis of the spindle, in this case said stop is constituted by the end of the second pinion 12 for the devices shown in Figures 2 to 15.

[0115] The drill comprises a motor (not shown) provided with a rotor R. It may for example be a pneumatic motor (with vanes), a pneumatic turbine or an electric motor. In this embodiment, the motor is a pneumatic turbine connected to a compressed air supply valve.

[0116] The drill comprises a transmission. This transmission is interposed between the rotor of the motor and the spindle. It is capable of transforming a rotational movement of the rotor in the working direction (i.e. drilling direction) into a rotational and / or translational movement of the output spindle 10 along the same axis, i.e. its longitudinal axis X.

[0117] This transmission includes:

[0118] - a first pinion 11 coaxial with the spindle 10 and provided with internal splines cooperating with the external longitudinal grooves of the spindle 10 (the first pinion and the spindle are thus linked by a linear connection along the longitudinal axis of the spindle);

[0119] - a second pinion 12 coaxial with the spindle 10 and provided with an internal thread cooperating with the thread 102 of the spindle 10 (the second pinion and the spindle are thus linked by a helical connection along the longitudinal axis of the spindle);

[0120] - a third pinion 13 with an axis parallel to the spindle 10, meshing with the first pinion 11 following a first transmission ratio and driven in rotation by the drill motor directly or by means of a pair of bevel gears 15 and / or one or more epicyclic gear trains (not shown);

[0121] - a fourth pinion 14 with an axis parallel to the spindle 10, meshing with the second pinion 12 following a second transmission ratio different from the first ratio.

[0122] In this embodiment, the first pinion 11 acts as an end-of-deployment stopper and the second pinion 12 acts as an end-of-retraction stopper.

[0123] The fourth pinion 14 comprises first dogs 140, in the form of ogives, capable of cooperating with clutch housings 130 of complementary shape arranged opposite each other on the third pinion 13 in such a way that when the dogs 140 are housed in the clutch housings 130, the fourth pinion 14 and the third pinion 13 are linked in rotation. The first dogs and the clutch housings thus constitute means for connecting the rotation of the third and fourth pinions.

[0124] The shape of the first dogs 140 and the clutch housings 130 is chosen in such a way that as soon as the fourth pinion tends to rotate relative to the third pinion, the first dogs 140 tend to come out of the clutch housings 130, causing the fourth pinion 14 to tend to move away, along its axis of rotation, from the third pinion 13. This principle, known per se to those skilled in the art, is for example described in the patent documents FR 2 881 366 and FR 2 918 592.

[0125] The fourth pinion 14 also comprises second dogs 141 of complementary shape to immobilizing dogs 17 fixed relative to the casing of the drill.

[0126] In a variant, the immobilizing dogs 17 are mounted to be movable in rotation relative to the casing along the axis of rotation of the fourth pinion 14 over a predetermined angular range against the effect of elastic return means. These elastic return means here take the form of elastomer springs 170 housed in grooves 171 in ring portions formed in the casing against one end of which fingers integral with the immobilizing dogs 17 come to bear.

[0127] The fourth pinion 14 is integral in translation with the rod 160 of a piston 161 of a first monostable (i.e. single-acting) cylinder 16, and free to rotate with respect to this rod. This piston 161 is movable in translation along the axis of rotation of the fourth pinion in a chamber 162 in such a way that the fourth pinion 14 can take:

[0128] - an engaged position in which the first dogs 140 are housed in the clutch housings 130 and the second dogs 141 do not cooperate with the immobilizing dogs 17 so that the fourth pinion 14 is linked in rotation with the third pinion 130 and is free to rotate relative to the casing, and

[0129] - an immobilized position in which the first dogs 140 do not cooperate with the clutch housings 130 and the second dogs 141 cooperate with the immobilizing dogs 17 so that the fourth pinion 14 is immobile in rotation relative to the casing and is not linked in rotation with the third pinion 13.

[0130] The fourth pinion 14 can also take an intermediate position. In In this intermediate position, it is interposed between the third pinion 13 and the immobilizing dogs 17. The first dogs 140 of the fourth pinion 14 are then located outside the clutch housings 130 of the third pinion 13 so that the fourth pinion 14 is not linked in rotation with the third pinion 13. In addition, the second dogs 141 do not cooperate with the immobilizing dogs 17 of the casing so that the fourth pinion 14 is also not linked in rotation with the casing. In other words, in this intermediate position, the fourth pinion 14 is free to rotate relative to the third pinion 13 and to the casing.

[0131] To move the fourth pinion 14 from its engaged position to its immobilized position, the side facing the fourth pinion 14 of the chamber 162 of the jack 16 is supplied with compressed air so as to move the fourth pinion 14 away from the third pinion 13 against the effect of the spring 163. To do this, the drill comprises a distributor (not shown) provided with a slide, this distributor being connected to a source of compressed air (not shown), and being able to take a supply state in which it is capable of supplying compressed air to the chamber 162 of the jack 16 to induce this movement of the fourth pinion 14.

[0132] The drill comprises a mechanism for acting on the distributor to place it in its supply state for the chamber 16 when, under the effect of the translational blocking of the spindle 10 by the arrival of the end-of-deployment stop 18 bearing against the end-of-deployment stop 11, the fourth pinion 14 rotates relative to the third pinion 13 and moves away from the third pinion 13 towards its immobilized position. This mechanism transforms such a movement of the fourth pinion 14 into a movement of the distributor slide placing it in a position in which the distributor is in its supply state and consequently supplies compressed air to the chamber 162 of the jack 16. A mechanism of this type is known per se to those skilled in the art and is for example described in patent documents FR 2 881 366 and FR 2 918 592.

[0133] To move the fourth pinion 14 from its immobilized position to its engaged position, the distributor slide is moved so as to put the distributor in a venting state in which it is able to vent the chamber 162 of the cylinder 16 so as to bring the fourth pinion 14 closer to the third pinion 13 under the effect of the spring 163.

[0134] The rod 160 of the cylinder 16 comprises a first end connected to the piston 161. Starting from the piston 161, the rod 160 comprises a first zone having a first diameter 1600 extended by a second zone having a second diameter 1601. The first diameter is greater than the second diameter. A shoulder 1602 is provided between the zones of large 1600 and small 1601 diameters.

[0135] The drill comprises a locking element. This locking element is in the form of a latch 23 having the shape of a portion of a ring. This latch 23 is mounted to move in rotation about an axis 24 parallel to the axis of the spindle 10 between:

[0136] - a passing position in which it is distant from the rod 160 of the jack 16 so well that the shoulder 1602 can freely pass the latch 23 when the rod 161 of the jack 16 moves the fourth pinion to its engaged position;

[0137] - a blocking position in which it is supported against the rod 160 of the jack 16 if although the shoulder 1602 may come into contact with the latch 23 when the rod 161 of the cylinder 16 moves the fourth gear towards its engaged position.

[0138] A spring acts on the latch 23 to tend to keep it in its locking position.

[0139] The drill comprises a second monostable (i.e. single-acting) cylinder 25 provided with a rod 250 which acts, when it deploys against the effect of the spring, on the latch 23 to move it into its passing position.

[0140] The shoulder 1602 is located along the rod 160 of the first jack 16 in such a way that when the latch 23 is in its locking position, bearing against the small diameter portion 1601 of the rod 160 and abutting against the shoulder 1602, the fourth pinion 14 is in the intermediate position.

[0141] The drill comprises means for actuating the distributor capable of placing it in its state of venting the chamber 162 of the first cylinder 16. These actuating means comprise: - an actuator 21 comprising a finger 22 movable in a chamber 23 against the effect of a spring 24, and - an actuating element 26 of the finger 22 of the actuator 21.

[0142] This actuating element 26 has the shape of a sleeve which is mounted to be able to rotate around the distal end of the spindle, i.e. the end intended to be connected to a cutting tool. It is also mounted to be able to move in translation along the distal end of the spindle. Elastic return means, such as elastic washers 27, are interposed between the actuating element 26 and the second pinion 12. These washers 27 tend to oppose the approach of the actuating element 26 to the second pinion 12. The actuating element 26 has on its external peripheral contour a hollow portion 260 of small diameter and a projecting portion 261 of large diameter. These portions define a cam profile capable of acting on the finger 22 of the actuator 21 to move it from one to the other of its positions.

[0143] The actuating element 26 is mounted to move in translation along the spindle 10 between:

[0144] - an inactive position in which it is kept away from the second pinion 12, bearing against a stop 200 formed in the casing, in such a way that the end of the finger 22 is located in the hollow portion 260 so that the finger 22 is in its supply position in which the distributor is in its state of supplying compressed air to the chamber 162 of the cylinder 16, and

[0145] - a venting position in which it is brought closer to the second pinion 12, against the effect of the elastic washers 27, in such a way that the end of the finger 22 is against the projecting portion 261 so that the finger 22 is in its venting position in which the distributor is in its venting state of the chamber 162 of the cylinder 16. This venting position of the actuating element 26 is reached when the retracted pin 10 compresses the elastic washers 27 between the second pinion 12 and the actuating element 26 via the end of retraction stop 19.

[0146] As long as the end of retraction stop 19 is not bearing against the end of retraction stopper 12 via the actuating element 26, the elastic washers 27 act on the actuating element 26 to move it away from the second pinion 12 and keep it in its inactive position in which the end of the finger 22 is against the hollow portion 260 so that the distributor is in its state of supplying the chamber 162 of the jack 16. At the end of retraction of the spindle 10, the end of retraction stop 19 comes to bear against the actuating element 26 and moves the latter in translation along the spindle 10 in the direction of the second pinion 12 against the effect of the elastic washers 27. When the end of retraction stop 19, the actuating element 26 and the second pinion 12 are in contact with each other, the retraction is completed and the actuating element 26 is in its venting position.The rod of the finger 22 is in abutment against the projecting portion 261 of the actuating element 26 so that the distributor is in its state of venting the chamber 162 of the cylinder 16.

[0147] The drill comprises an actuating trigger. This actuating trigger is movable between: - a released position; - an initialization position allowing the latch 23 to move into its passing position; - a power supply position of the motor to perform a drilling cycle.

[0148] The drill comprises control means 300 comprising pneumatic logic components, in particular the distributor, which conventionally make it possible to control the operation of the pneumatic functions of the drill.

[0149] In the present embodiment, these control means are designed to: - when the trigger is in the initialization position, actuate the second cylinder 25 so as to place and maintain, as long as the trigger is pressed by a operator, the locking element 26 in its unlocked position, to allow the fourth pinion to move from its intermediate position to its engaged position; - when the trigger is in the motor supply position, control the opening of the motor supply valve which remains open after the trigger is released until the end of the drilling cycle or the activation of an emergency stop, so as to: - rotating the third 13 and fourth 14 pinions relative to each other to allow the first dogs 140 of the fourth pinion 14 to synchronize with the clutch housings 130 of the third pinion 13 and to gradually fit therein; - drive the spindle in movements to carry out a drilling cycle.

[0150] The engine is started after the fourth pinion has come into contact with the third pinion, so that the synchronization of the first dogs 140 with the clutch housings 130 takes place at a moderate rotation frequency of the third pinion and thus avoids shocks detrimental to the first dogs and the clutch housings. This time shift is obtained by two means: - pressing the trigger in two stages, i.e. initialization position then engine supply position. The opening of the engine supply valve is therefore caused after the release of the fourth pinion. - a small-section pneumatic conduit between the trigger and the motor supply valve opening control. This small section induces a pressure drop on the air flow controlling the valve opening and therefore a slight delay in opening.

[0151] The trigger is held in the motor feed position for a short time to initiate the drilling cycle which continues to run until completion after the operator releases the trigger which returns to the released position. 6.2. Operation

[0152] This type of drill can also be used to make holes with or without countersinking at the hole entry.

[0153] The flowchart placed in [Fig.18] illustrates the operation of the device as described below.

[0154] 6.2.1. Drill stopped before starting: fourth gear in position in intermediate

[0155] Before starting the drill to perform a drilling operation, the spindle 10 is fully retracted so that the end of retraction stop 19 bears against the actuating element 26 and compresses the elastic washers 27 between the latter and the second pinion 12 which constitutes the end of retraction stop.

[0156] The actuating element 26 is in its venting position in which the finger 22 is in its venting position.

[0157] The distributor is in its state of venting the chamber 162 of the first cylinder 16.

[0158] The spring 163 acts on the piston 161 so as to tend to bring the fourth pinion 14 closer to the third pinion 13.

[0159] The control means do not supply the second cylinder 25 in such a way that the spring maintains the locking element 23 in its blocking position in which it is in abutment against the small diameter zone 1601 of the rod of the cylinder 16 and against the shoulder 1602.

[0160] The fourth pinion 14 is thus held in an intermediate position. 6.2.2. Starting the drill

[0161] i. Initialization phase: passage of the fourth gear from the intermediate position to the engaged position

[0162] To start the drill, an operator actuates the trigger so as to place it momentarily in the initialization position and then in its motor supply position.

[0163] The control means actuate the second cylinder 25 to place the locking element 23 in its passing position, against the effect of the spring. This has the effect of moving the locking element 23 away from the rod 160 of the cylinder 16 in such a way that it extends beyond the large diameter zone 1600.

[0164] This releases the movement of the piston 161 which, under the effect of the spring 163, tends to move the fourth pinion 14 from its intermediate position to its engaged position.

[0165] Then after a short time the engine starts causing the finalization of the movement of the fourth pinion into its clutch position in which it is linked in rotation with the third pinion.

[0166] The operator releases the trigger which returns to its released position.

[0167] When the operator releases the trigger, the control means cuts off the power supply to the second cylinder 25 so that the locking element 23 comes to bear against the large diameter zone 1600 of the rod 160 of the first cylinder 16 under the effect of the spring, while the motor power supply valve remains in the open position. ii. Drilling phase

[0168] The fourth pinion 14, which is rotatably connected with the third pinion 13 and the motor rotates at its nominal rotation frequency.

[0169] The first pinion 11 is rotated by the third pinion 13 so that spindle 10 is rotated along its longitudinal axis.

[0170] The second pinion 12 is driven in rotation by the fourth pinion 14.

[0171] The reduction ratio between the first 11 and the third pinion 12 is different from the reduction ratio between the second pinion 12 and the fourth pinion 14. Thus, taking into account the helical connection between the second pinion 2 and the spindle, the spindle is driven in translation along its axis and deploys outside the casing until the end of deployment stop 18 is in abutment against the first pinion 11 which constitutes the end of deployment stop.

[0172] During this period the drill is driven along a helical trajectory with an adequate cutting and feed speed, thus achieving the expected drilling.

[0173] iii. End of deployment of the spindle: passage of the pinion into the immobilized position

[0174] When the end of deployment stop 18 is in abutment against the end of deployment stopper, the deployment of the spindle 10 is stopped. The third 13 and the fourth 14 pinions therefore tend to rotate at different speeds. Thus, taking into account the ogive shape of the first dogs 140 of the fourth pinion 14, these dogs 140 tend to come out of the clutch housings 130 of the third pinion 13 so that the fourth pinion 14 moves away from the third pinion 13 towards its immobilized position.

[0175] This relative distance of the fourth pinion 14 from the third pinion 13 induces the passage of the distributor into its supply state of the chamber 162 of the cylinder 16 so that the side oriented towards the fourth pinion 14 of the chamber 162 of the cylinder 16 is supplied with compressed air. As a result, the piston 162 of the cylinder 16 drives, against the effect of the spring 163, the fourth pinion 14 into its immobilized position in which its second dogs 141 cooperate with the immobilization dogs 17. The fourth pinion 14 is then immobile in rotation relative to the casing without being linked in rotation to the third pinion 13.

[0176] During this movement, the locking element 23 (i.e. the latch), which is held in abutment against the rod 160 of the first jack by the spring, slides first against the large diameter zone 1600 then against the small diameter zone 1601 of the rod 160. Thus, when the fourth pinion 14 is in the immobilized position, the locking element 23 is in abutment against the small diameter zone 1601 of the rod 160 while being distant from the shoulder 1602.

[0177] In the variant according to which the immobilizing dogs 17 are movable against the effect of the elastomer springs 170, the engagement of the second dogs 141 with the immobilizing dogs 17 is damped.

[0178] Given that the fourth pinion 14 is immobilized in rotation, the second pinion 12 is also immobilized in rotation. Thus, the spindle continuing to be driven in rotation by the third 13 and the first pinion 11, moves in translation along its axis in the direction of retraction inside the casing.

[0179] iv. End of spindle retraction: passage of the fourth pinion into intermediate position

[0180] The retraction of the spindle 10 is carried out until the end of retraction stop 19 moves the actuating element 26 into its venting position by compressing against each other the end of travel stop 19, the actuating element 26 and the second pinion 12 which constitutes the end of retraction stop.

[0181] The pin 10 is then completely retracted and the actuating element 26 places the finger 22 in its venting position, in which the distributor is in its venting state of the chamber 162 of the cylinder 16, while the control means cut off the power supply to the motor.

[0182] The chamber 162 of the first cylinder 16 empties while the piston 161 moves in the chamber 162 under the effect of the spring 163 inducing a movement of the fourth pinion 14 from its immobilized position towards its engaged position.

[0183] During this movement of the piston 162, the shoulder 1602 comes into abutment against the locking element 23, thus blocking the fourth pinion 14 in its intermediate position in which it is free to rotate with respect to the third pinion 13 and the casing.

[0184] Although the power supply to the motor is cut off, the rotor of the motor can continue to rotate in the working direction under the effect of its inertia. This is particularly the case for high-speed motors, for example of the order of 60,000 revolutions per minute, and having little internal friction. However, since the fourth pinion 14 is in its intermediate position in which it is free to rotate, the rotational drive of the third pinion 13 under the effect of the dissipation of the kinetic energy of the rotor, induces a rotation of the spindle 10 but no translational movement thereof.

[0185] In this way, the invention makes it possible to guarantee that at the end of the retraction phase of a drilling cycle, and the complete stopping of the motor after dissipation of its kinetic energy, the spindle is systematically completely retracted so that at the start of the following drilling cycle the available travel for deployment of the spindle is total. Thus, at the start of each drilling cycle, the available travel for deployment of the spindle is total.

[0186] The drill is then in the state it was in before it was started so that a new cycle can be started by actuating the trigger. 6.3. Terminology

[0187] The means for holding the fourth pinion 14 in the intermediate position at the end of the retraction stroke of the spindle include in particular the shoulder 1602, the locking element 23 (or latch) and the spring which tends to hold it against the rod 160 of the first cylinder 16.

[0188] The means for driving the fourth pinion 14 into the intermediate position include in particular the spring 163 which acts on the piston 161.

[0189] The means for holding the fourth pinion 14 in the engaged position include in particular the spring 163 which acts on the piston 161.

[0190] The means for holding the fourth pinion 14 in the immobilized position comprise in particular the first jack 16 and its supply distributor. 6.4. Integration of a vibrator

[0191] An example of an embodiment of a drill according to the invention equipped with a vibrator is presented in relation to figures 16 and 17. 6.4.1. Function of the vibrator

[0192] The vibrator is a mechanical device which, when used on a drilling device, allows an alternating component to be added to the feed movement of the spindle. This component allows the lips of the drill bit connected to the spindle to come out of the material several times per revolution and thus fragment the chips. This makes the chips easier to extract from the hole during drilling and this limits the risk of jamming or damage to the hole wall.

[0193] Some drillings require to be finished, in the same operation by a countersink. This countersink is intended to contain the conical head of a rivet and a perfect complementarity must exist between the cones of the rivet and the countersink, this to ensure a perfect seal of the pierced structure. It is therefore important that the surface of the countersink is free of waves which would result from the alternating feed component. Also the vibrator must be deactivated at the end of the countersinking to obtain a perfect conicity. 6.4.2. Composition of the vibrator

[0194] The vibrator is presented as a roller thrust bearing, one of the tracks of which has undulations, so when the tracks rotate relative to each other, the thickness of the vibrator varies between minimum and maximum values, several times per revolution.

[0195] This is achieved by the design shown [Fig. 16].

[0196] The first pinion 11 is guided in rotation relative to the casing 20 by means of a bearing 30. The second pinion 12 is guided in rotation relative to the casing 20 by a bearing 31. The first 11 and second 12 pinions are guided in rotation relative to each other by means of a ball thrust bearing 32.

[0197] The vibrator comprises a first track 33, without surface undulation, coming to bear against the bearing 30. It also comprises rollers 34 which come in pressing against the first track 33. The vibrator further comprises a second track 35 having surface undulations.

[0198] The drill comprises a ball thrust bearing 37 which acts as the end-of-deployment stop. This ball thrust bearing 37 is mounted on a ring 39 fixed relative to the casing 20. This ring 39 comprises, oriented in the direction of the bearing 30, a surface 390 against which one end of a compression spring 40, called the countersinking finalization spring, bears. The other end of the spring 40 is housed in a ring 41 which bears against the bearing 30.

[0199] A spring 36 is arranged between the bearing 31 and the second pinion 12 to tend to press the elements constituting the vibrator against each other and against the bearing 30. 6.4.3. Operation of the vibrator i. In drilling action

[0200] In drilling action, the stacking of the following parts is used to generate the reciprocating feed component (vibrating feed), from left to right in [Fig.16]: - the outer ring of the bearing 30, itself linked to the casing 20 of the drilling device. - the first track 33 of the vibrant - the rollers 34 of the vibrating - the second track 35 of the vibrant - the first pinion 11 generating the rotation of the spindle 10 - the second pinion 12 generating the rotation of the spindle 10, this pinion 12 is separated from the first pinion 11 by a row of balls 320 acting as a stop. - the return spring 36

[0201] In drilling action, due to the rotation of the first pinion 11 relative to the casing 20, the tracks 33, 35 of the vibrator rotate relative to each other, this inducing an alternating axial movement of the first pinion 11. This movement is transmitted to the second pinion 12 then to the spindle 10, this inducing the alternating feed component at the lips of the drill. ii. In the process of finalizing the milling

[0202] In the action of finalizing the countersinking, the end of deployment stop 18 comes into contact with the end of deployment stop, i.e. in this variant the ball thrust bearing 37. The axial movement of the spindle 10 is interrupted while the spindle 10 continues to rotate through an angle of the order of one turn. This makes it possible to finalize the surface of the countersinking without undulation.

[0203] Meanwhile, the second pinion 12 continues to rotate. Since the spindle 10 is axially immobile, the second pinion 12 moves under the action of the thread of the spindle 10 in the direction of the deployment end stop 18. To allow this movement, the milling completion spring 40 collapses, giving time for the milling to be completed. When the milling completion spring 40 can no longer collapse, the second pinion 12 stops moving axially and starts to rotate at the same rotation frequency as the first pinion 11, this triggering the retraction of the spindle 10 as explained above.

[0204] The stiffness of the countersinking finalization spring 40 is also sufficiently strong so that it does not collapse during the drilling action and does not disturb the generation of the alternating feed component.

Claims

Claims

1. A drilling device comprising a housing housing: - a motor comprising a rotor capable of rotating in a working direction; - a transmission; - a drilling spindle capable of being driven in rotation and / or translation along a longitudinal axis of said spindle via said motor and said transmission; said transmission comprising: - a first pinion linked in rotation with said spindle and mounted to move in translation along said spindle following said longitudinal axis of said spindle; - a second pinion linked to said spindle by a helical connection along said longitudinal axis of said spindle; - a third pinion, meshing with said first pinion, and capable of being driven in rotation by said motor; - a fourth pinion, meshing with said second pinion, said fourth pinion being movable between: - an engaged position in which it is linked in rotation with said third gear by connecting means, the rotational driving of said third pinion by said motor in said working direction inducing deployment of said spindle over a predetermined deployment stroke; - an immobilized position in which it is linked in rotation with said casing and it is free in rotation with respect to said third pinion, a rotation of said third pinion by said motor in said working direction inducing a retraction of said spindle following a predetermined retraction stroke, characterized in that said fourth pinion is capable of taking an intermediate position in which it is free in rotation with respect to said casing and said third pinion in such a way that it does not exert substantially any torque on said second pinion so that a rotational drive of said third pinion by said motor induces a rotation of said second pinion at the same rotational frequency as that of said spindle.

2. A drilling device according to claim 1 comprising means for holding said fourth pinion in said intermediate position at the end of said retraction stroke of said spindle.

3. A drilling device according to claim 1 or 2 comprising: - an end-of-deployment stop carried by said spindle and capable of coming to bear against an end-of-deployment stopper, said end-of-deployment stopper being axially fixed relative to said casing; - an end-of-retraction stop carried by said spindle and capable of coming to bear against an end-of-retraction stopper, said end-of-retraction stopper being axially fixed relative to said casing; - a first cylinder comprising a rod capable of axially moving said fourth pinion between said engaged and immobilized positions, - means for controlling said first cylinder configured to: - move said rod in a first direction inducing a movement of said fourth pinion from said engaged position to said immobilized position when said end-of-deployment stop touches said end-of-deployment stopper;- moving said rod in a second direction inducing a movement of said fourth pinion from said immobilized position to said engaged position when said end of retraction stop touches said end of retraction stopper.;

4. A drilling device according to claim 3 wherein said first cylinder is a single-acting cylinder comprising a chamber in which said first rod is capable of sliding against the effect of elastic return means, said control means being capable of: - supplying compressed air to said chamber of said cylinder to induce said movement in said first direction, said control means of said first cylinder acting on said distribution means to trigger said supply when said end-of-deployment stop touches said end-of-deployment stop; - exposing said chamber to the atmosphere, when said end-of-retraction stop touches said end-of-retraction stop, so as to induce said movement in said second direction under the effect of a relaxation of said elastic return means of said first cylinder.

5. Device according to any one of claims 2 to 4 wherein said means for holding said fourth pinion in said intermediate position comprise: - a shoulder provided on said rod of said first jack, said shoulder separating two zones of said rod: - a first zone having a first diameter extending on the side of said piston of said first cylinder; - a second zone having a second diameter extending on the side of said fourth pinion, said second diameter being less than said first diameter; - a latch capable of occupying: - a blocking position in which said shoulder can come into contact with said latch when said rod is moved in said second direction, the fourth pinion occupying said intermediate position when said shoulder is in contact with said latch; - a passing position in which said shoulder can freely pass over said latch when said rod is moved in said second direction.

6. Device according to claim 5 wherein said latch is: - linked in rotation at one of its ends around an axis parallel to said rod of said first cylinder and fixed in said casing; - connected at the other of its ends to a second single-acting cylinder, said device comprising means for controlling said second cylinder configured to activate said second cylinder in order to move said latch towards one or other of the blocking or passing positions.

7. Device according to any one of claims 1 to 6 wherein said fourth pinion comprises first dogs and said casing comprises second dogs, said first and second dogs being configured to connect in rotation said fourth pinion and said casing in said immobilized position, said second dogs being mounted mobile in rotation along the axis of rotation of said fourth pinion over a predetermined angular range against the effect of third elastic return means.

8. A method of drilling an element during a drilling operation by means of a drilling device according to any one of claims 1 to 7, said method comprising a step of positioning and holding said fourth pinion in said intermediate position in which it is free to rotate relative to said housing and said third pinion in such a way that it exerts substantially no torque on said second pinion so that rotational driving of said third pinion by said motor induces rotation of said second pinion at the same rotational frequency as that of said spindle.

9. A method according to claim 7 comprising, following a contact of said end-of-deployment stop with said end-of-deployment stopper: - a step of retracting said spindle until said end of retraction stop is in contact with said end of retraction stopper; - a step of stopping the power supply to said motor; - said step of moving and maintaining said fourth pinion in said intermediate position; - a step of residual rotation of said rotor, under the effect of its kinetic energy, until immobilization of said rotor after said kinetic energy is absorbed, said rotor driving in rotation, during said step of residual rotation, said third pinion, and said fourth pinion during this rotation exerting substantially no torque on said second pinion so that said spindle is immobile in translation.

10. A method according to claim 8 comprising: - a step of starting said drilling device in order to carry out said drilling operation, - a step of positioning said fourth pinion in said engaged position at the end of said step of starting the device and prior to carrying out said drilling operation.

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