FR2881366A1 - AUTOMATIC STOP MACHINING MACHINE AT THE END OF THE CYCLE - Google Patents

Abstract

The machine comprises a pinion (6) axially connected to a piston (8), the assembly being subjected to the force of a spring (8b) maintaining, during the machining phase, the upper jaw teeth (6d) in triangular sawtooth form, in that corresponding to it (3d) of the input pinion (3), and closing by the upper face of the piston (8) the orifice of a channel (10a) connected to the pressure chamber maintaining the opening of a valve (20) supplying the pneumatic motor (1). At the end of the machining phase, the pinion (6) being locked in rotation, initiates an axial movement of declutching by the obliqueness of the faces of the support of the teeth (3d, 6d), the piston (8) then subjected to the pressure coming through the channel (10a), pulls the pinion (6) by interconnection, by its lower toothing (6c) in that corresponding to it (11d ) of the fixed plate (11) .The pressure on the piston (8) is led by a channel (13c) in a leakage sensor (13) which opens at the end of raising of the spindle (12) by its boss ( 12b), resulting in the closure of the valve (20) and the engine stop (1). The machine is intended for industry, especially aeronautics.

Description

The present invention relates to a machine of the type

comprising <

  a pneumatic motor, a pneumatic circuit for connecting the motor to a source of compressed air, and comprising an engine supply valve, a tool spindle, a drive mechanism mechanically connecting the motor to the pin for driving it, the mechanism comprising a selection member movable between a first selection position of a first drive mode of the spindle, and a second selection position of a second 1; 0 drive mode of the spindle different from the first driving mode, a device for controlling the operation of the machine for controlling the execution of a training cycle comprising at least one step of training the spindle according to the first training mode then a step of stripping the spindle according to the second drive mode, and then controlling the stopping of the air supply of the motor.

  The first step of the cycle is generally a step of simultaneous advance and rotation of the spindle, and the second step a step of simultaneous recoil and rotation of the spindle.

  The device for controlling the operation of the machine makes it possible to automatically stop the operation of such a machine after the execution of a cycle.

  Thus, when a user has installed several of these machines on a support grid and triggered their operations, the machines stop automatically without having to intervene specifically on each one of them. .

  In machines of the aforementioned type, the operation control device comprises elements of the pneumatic circuit dedicated to controlling the closure of the engine supply valve at the end of the step of retreating the spindle.

  These machines are mainly used for drilling and milling, especially in aeronautical construction.

  It can be seen that the structure of the control device is relatively complex and expensive, in particular because of these dedicated pneumatic elements.

  The object of the invention is to provide a machine of the aforementioned type which is lighter, less bulky, more simple structure and lower cost; A machining machine according to the invention comprises: - a pneumatic motor (1), - a pneumatic circuit for connecting the motor (1) to a source of compressed air via a valve (20) allowing its operating and stopping thereof, - a tool spindle (12), - a drive mechanism connecting the motor (1) to the spindle (12) to drive it, the mechanism comprising a selection assembly (6-8a) 8) movable between a first position defining a first mode of driving in rotation and in axial translation of the spindle (12) downwards corresponding to the step of machining the cycle, and a second mode of training in rotation and in axial translation of the spindle (12) upwards corresponding to the return step at the end of the cycle, - a pneumatic device for executing the cycle and controlling the stopping of the supply of compressed air to the engine (1 ) at the end of the cycle.

  The facing faces of the pinion-clutch (6) of the movable selection member (6-8a-8) and the input gear (3) of the mechanism, comprise, on the same ring, identical salient elements they are in the same number as cavities identical to each other and capable of receiving them. The section of the salient elements is zero at their extremity, and, of the salient element and the cavity, the section of at least one of them. The section of the projecting elements and that of the cavities at their respective bases leave on the annular surface of their interpenetration no flat surface providing support at the ends of the projecting elements. .The selector member (6-8a-8) is constantly biased towards the input gear (3) by a spring (8c) acting on the underside of a piston (8) and whose force maintains the interconnection gears (6 and 3) during the machining step. The pinion (3) being in rotation, the blo cage of the pinion-dog-clutch (6) causes its declutching by one oblique of the trajectory of the sliding supports of the elements projecting on the wall of the cavities from which they come out, this oblique trajectory prints to the selector member (6-8a-8) an axial movement.

  During the stop of the machine and the machining step, the piston (8) closes with a seal (8b) on its upper face, the orifice of a channel (10a) for supplying compressed air into the the upper wall of the chamber (9) of the piston (8), and the axial movement resulting from the disengagement of the pinion (6) of the inlet pinion (3), releases the compressed air flow arriving via the channel (10a ) which is exerted on the piston (8) by pulling the pinion (6) in interconnection on the fixed element (11) by the interpenetration of their jaw teeth (6c, 11d).

  The pressure prevailing above the piston (8) is driven by a passage (13c) coming from the upper part of the chamber (9) of the piston (8) and ending at the feed inlet of a pneumatic sensor acting in closing the valve (20) to stop the motor at the end of the cycle.

  The flow rate of the pressure arriving in the opening holding chamber (21) of the one-shot valve (20) closed by its spring (19) and that arriving in the channel (10a) is limited through a calibrated nozzle. (15) connected in stitching of the outlet flow of the valve (20) supplying the engine (1).

  The sensor (13) is a leakage sensor, the valve (13a) is pressed at the end of the axial translation step of the spindle (12) upwards, by its boss (12b), and empty at the bottom. atmosphere the holding chamber (21). in., opening of the valve (20) with a flow rate greater than that of the pressure passing through the calibrated nozzle (15), thus causing the closing of the valve (20) by the action of its spokes (19), and stopping the engine (1).

  According to an embodiment according to the invention, the projection (6d) of interconnection on the upper face of the pinion (6) and the toothing (3d) of interconnection on the underside of the pinion (3), are identical, and present a sawtooth appearance extending radially in a succession of prismatic teeth.

  According to another embodiment according to the invention, one of the facing faces of the pinions (6 and 3) comprises projecting elements of substantially semispherical shape, on the same ring and of the same number as substantially conical cavities. on the face of the other pinion, such as the circles of their base are tangent.

  According to another embodiment of the invention, each of the faces facing the pinions (6 and 3) comprises on the same ring, the same number of projecting elements whose surface of their section at their end is zero, alternating with cavities whose walls are oblique with respect to their piercing plane, the surface of the projecting elements and that of the cavities at their bases, leave no flat surface between them.

  In a machine according to the invention, the conical pinion gear (3a) of the mechanism meshing with the bevel gear (2) of the motor (1), the gear pinion with right teeth (3b) and the elements allowing the interconnection with the pinion -craboteur (6), constitute a monoblock manufacturing assembly.

  In a machine according to the invention, the stop (12a) adjustable along the upper part of the spindle (12) bears on the shoulder (4a) of the pinion (4) emerging outside the housing. (10) of the machine: the stop (12a) and its support (4a) rotating to: vesses.

  The invention will be better understood on reading the following descriptions, given solely as examples, and made with reference to the accompanying drawings, in which: FIGS. 1 to 4 are views detailing the drive mechanism and the device for controlling the operation of machines according to the invention. FIGS. 1 to 3 show, in section, the same machine in three different states. Figure 4 shows in section, a second machine con-form the invention in the off position.

  In the following descriptions, the terms "lower" and "upper", "horizontal" and "vertical", "right" and "left", "up" and "down", "above" and "below 15, s" mean in relation to the figures.

  According to Figure 1, the machine is stopped, it essentially comprises: - a conventional pneumatic motor 1, fixed to the casing 10 of the machine. a tool-holder pin 12 received in the casing 10 to be movable in rotation and in translation along its axis A with respect to the casing 10. conventionally, drilling tools can be mounted to be removable lower end 12c of the spindle 12.

  The mechanism includes; a gear gear 2 rotatably connected to the output shaft 25 of the engine 1, a first double gear 3 on the axis B having a first gear 3a meshing with the motor gear 2, and a second gear 3b meshing with a pinion 4 on the axis A causing rotation pin 12, said pin being slidable along its axis A relative to this pinion, the axes A and B being parallel.

  - A second pinion-double clutch 6 below the pinion 3 meshing with a pinion 5 with straight teeth on the axis A, below the pinion 4.1e pignce 5: is screwed on the threaded length of the pin 12, its rotation being independent that of the pinion 4 by a ball path 45, and all of the two pinions 4 and 5 is immobilized in the vertical direction in the housing 10.

  A tray 11 with jaws 11d fixed in the housing 10, centered on the axis B below the double gear / clutch 6.

  The first double pinion / dog 3 is rotatably mounted around the rod 7 fixed along the axis B in the housing 10.

  The second pinion / double clutch 6 is rotatably mounted around the end of the tubular portion 8b of the pneumatic piston 8 which can slide by their peripheral seals in a sealed manner in their respective cylindrical bores in the casing 10, the assembly 6, 8a, 8 sliding along the rod 7 is the selection member stages of the machine cycle.

  The gear teeth on the upper face of the pinion 6 have a serrated saw tooth appearance: sibly-angled, which are capable of engaging in the sharp-toothed 3d gear teeth on the lower face of the pinion 3; resting, the piston 8 equipped with an annular flat seal 8b mounted around 8a on its upper face, closes the orifice of a channel 10a opening into the upper surface of its cylindrical chamber 9, by the force of a spring ac acting on the underside of the piston 8 to maintain the selector 6-8a-8 in the up position.

  The machine also comprises a valve 20 of normally closed type monostable spring return closure by its spring 19 and able to maintain opening by a pneumatic pressure exerted on the face of its drawer opposite the spring 19 in its chamber 21 in: open.

  The valve 20 for supplying compressed air to the machine, comprises a manual control 22 mechanically connected to the drawer to allow its opening and the start of the machine.

  A pneumatic circuit comprising; a link 17 from the output of the valve 20 to the inlet 1a of the motor; a line 16 stitched onto the link 17 and connected to a calibrated flow restrictor nozzle; a first conduit 14a connecting the outlet of the the nozzle 15 at the inlet of the channel 10a in the casing 10, and a second muffler 14b also issuing from the outlet of the nozzle 15 and connected to the control chamber 21 of the valve 20.

  a channel 13c in the upper part of the cylindrical wall of the piston chamber 8, and opening into the chamber of a leakage sensor 13 behind its valve 13a urged into closure by a res-spell 13b.

  The machine still has; - An upper stop 12a adjustable along the pin 12 and bearing on a shoulder 4a of the pinion 4 and protruding outside the carter-ter 10, the abutment 12a and the bearing shoulder 4c rotating on speed.

  a boss 12b fixed on the lower part of the pin 12, able to depress the control 13a of the leakage sensor 13 at the end of the ascent of the pin 12, marking the end of the operating cycle.

  When the machine is stopped as shown in FIG. 1, the toothing 6d with triangular tooth profile is firmly held in engagement with its counterpart 3d of the pinion 3 by the upward pushing of the spring so that during the step machining of the machine, the pinion 6 is driven by the pinion 3 to resist the torque necessary for 1! machining; .thepoussée spring. during this first step ensures the closure of the orifice of the channel 10a.

  A pull on the manual control 22 of the valve 20 releases the passage of the operating pressure to the opening 1a of the engine 1 which starts, a small flow of air passing through the calibrated nozzle 15 fills the pipe 14a and the channel 10a , as well as the pipe 14b and the chamber 21 of the valve 20 which is kept open.

  According to FIG. 2, the arrival of the stop 12a of the pin 12 on the shoulder 4a of the pinion 4 marks the end of the machining step, the tool having reached the depth of cut determined by the adjustment of said stop 12a. The immobilization in translation of the spindle provokes, by the differential effect resulting from the ratio between the primitive diameters. sprockets 3-4 and 6-5, the locking in rotation of the pinion 6. The obliquity of the bearing faces of the teeth 3d and 6d causes a translational primer to the bottom of the assembly 6-8a-8; 1 ' orifice of the channel 10a thus open, the pressure flow is exerted on the active face of the piston 8 which pulls the pinion 6 downwards, and whose jaw clutch 6c engages in the teeth of interconnection 11d of the fixed plate 11 The pressure above the piston 8 fills, through the channel 13c, the sensor 13 at the rear of its valve 13a: still: .closed.

  FIG. 3 shows the machine in its step of raising the spindle 12 unscrewed in the thread of the pinion.5 locked in rotation by the immobilization of the pinion 6.The boss 12b of the pin 12 arriving at the height of the leakage sensor 13 presses its valve which empties, at a much higher flow rate than that which can pass through the nozzle 15, all the pressure above the piston 8 and in the chamber 21 for maintaining the opening of the valve 20 which closes automatically and stops the pneumatic motor 1.

  Figure 4 is a sectional representation of a mechanism of a ma-chine according to the invention.

  In this mechanism, the upper face of the drive gear 6 has a number of projecting elements 6d of substantially semispherical shape arranged in a ring, the lower face facing the pinion 3 is pierced with the same number of substantially conical cavities, arranged on the same circle as the crown of the projecting elements, such that the drilling circles they present are tangent and leave only sharp edges on this circle, in these conditions the projecting elements 6d do not meet, at their penetration in the 3d cavities adapted to receive them, no flat surface can oppose it, and the locking of the pinion 6, while turn-pinion 3, causes the clearance of the projecting elements 6d cavities 3d according to the oblique trajectory of their sliding support contacts, leading to an axial downward movement of the pinion 6-link 8a - piston 8.The compressed air supply channel 10a now open the supply valve a pneumatic motor, opens in the mechanism on a cylindrical chamber created by the greater play at this point between the link 8a and its sliding bore in the housing 10. The axial movement down the whole 6-8a 8, the effect of releasing the pressure flow from the channel 10a on the active face of the piston 8, by the loss of seal hitherto provided by the O-ring 8b on the face of the piston 8 surrounding the element of link 8a at its base.

  As previously explained, the pressure acting on the piston 8 leads to the interconnection of the cylindro-conical projecting elements 6b in the tronco-cylindrical holes 11d their corresponding in the fixed part 11, thus marking the end of the machining step of the cycle The pressure above the piston 8 extends through an opening 13c into a leakage sensor 13 behind its valve 13a.

  In another embodiment of a mechanism not shown according to the invention, each of the facing faces of the gears 6 and 3, comprise in equal number and on the same circle, an alternation of projecting elements whose surface of their section becomes none at their extremity, and cavities adapted to welcome them, whose surface of section which they present on the face of the gables, decreases progressively with their depth.

  The outline of the sections of the projecting elements at their base and that of the cavities touch on the circle of their implantation to leave no plane surface on which the end of the projecting elements can rest at the moment of their penetration into the cavities.

Claims (10)

  Machining machine of the type comprising: a pneumatic motor (1) a pneumatic circuit for connecting the motor (1) to a compressed air source 5 via a valve (20) allowing its operation and stopping thereof, a tool spindle (12), a drive mechanism connecting the motor (1) to the spindle (12) to drive it, the mechanism having a movable selection assembly (6-8a-8) between a first position determining a first mode of driving in rotation and in downward axial translation, the spindle (12) corresponds to the step of machining the cycle, and a second mode of driving in rotation and in axial translation. towards the top of the spindle (12) corresponding to the return step at the end of the cycle, a pneumatic device for the execution of the cycle and to control the stoppage of the compressed air supply of the engine (1) at the end cycle, characterized in that the faces opposite the. pinion gear (6) of the selectibnmobile member (6-8a-8) and the input pinion (3) of the mechanisme comprise, on the same ring, identical salient elements among them, in the same number as identical cavities between them and able to receive them, that the surface of section of the projecting elements is zero at their extremity, that, of the projecting element and of the cavity, the section of at least one of them is reduced progressively in relation to its section at its base, that the section of the salient elements and that of the cavities at their respective bases leave on the annular surface of their interpenetration no flat horizontal surface offering support to the ends of the projecting elements; and that the selection member (6-8a-8) is constantly biased towards the input gear (3) by a spring (8c) acting on the lower face of the piston (8) and whose force maintains the clutching of the gears (6,3) during the machining step, and that, the pinion (3) being rotated, the locking of the pinion gear (6) causes its declutching by the obliquity of the trajectory of the sliding supports of the projecting elements on the laparoid cavities from which they come out, and that this oblique trajectory prints to the selector (6-8a-8) -an axial movement.   2. Machine according to claim 1 characterized in that, during its stop and the machining step, the piston (8) closes with a seal (8b) on its upper side, the orifice of a channel (10a) supplying compressed air into the upper wall of the chamber (9) of the piston (8) and the axial movement resulting from the clutching of the pinion (6) of the input gear (3) releases the air flow rate compressed arriving through the channel (10a) which is exerted on the piston (8) eh pulling the pinion (6) in interconnection on the fixed element (11) by 1 interpenetration of their jaw teeth (6t, 11d).   3. Machine according to claims 1 and 2, characterized in that the pressure above the piston (8) is driven by a passage (13c) from the upper part of the chamber (9) of the piston (8) and the above the piston in its upper position, and leading to the inlet_a power of a pneumatic sensor acting to close the valve (20) to stop the engine at the end of the cycle.   4. Machine according to claims 1,2 and 3, characterized in that the flow rate of the pressure arriving in the chamber (21) holding the opening of the valve (20) monostable spring return by its spring (19) and the one arriving in the channel (10a) is limited through a calibrated nozzle (15) connected in tapping of the outlet flow of the valve (20) supplying the engine (1) 5. Machine according to claims 1 to 4, characterized in that the sensor (13) is a leakage sensor, whose valve (13a) is depressed at the end of the axial translation step of the pin (12) to the top, by its boss (12b), and emptying the chamber (21) for holding the valve (20) open at a higher flow rate than the pressure passing through the calibrated nozzle (15) , thus causing the valve (20) to close by the action of its spring (19), and the stopping of the motor (1).   6. Machine according to claim 1, characterized in that _la de riture (6d) of interconnection on the upper face of the pinion (6) and the toothing (3d) of interconnection on the underside of the pinion (3), are identical and have a sawtooth appearance extending radially in a succession of prismatic teeth.   7. Machine according to claim 1, characterized in that one of the facing faces of the pinions (6 and 3) comprises salient elements :: of substantially semi-spherical shape, on the same crowned and of the same number as cavities substantially conical on the face of the other pinion, and that the base circles of these conical cavities are tangent.   8.Machine according to claim 1, characterized in that each of the faces facing the pinions (6 and 3) comprises on the same ring, the same number of projecting elements whose surface of their section at their end is zero, alternating with cavities whose walls are oblique with respect to their piercing plane, and that the surface of the projecting elements and that of the cavities at their bases, leave no flat surface between them.   9. Machine according to any of the claims, characterized in that the bevel gear (3a) input mechanism meshing with the bevel pinion (2) of the motor (1), the gear tooth gear right (3b) and the elements allowing the clutch interconnection with the pinion-clutch (6) constitute - a: -en, monobloc manufacture (3).   10. Machine according to any claim characterized in that the stop (12a) adjustable along the upper portion of the pin (12) abuts on the shoulder (4a) of the pinion (4) emerging outside the housing (10) of the machine, the stop (12a) and its support (4a) rotating at the same speed.