FR2755892A1 - IMPROVED PNEUMATIC SCREWDRIVER - Google Patents

Abstract

Pneumatic screwdriver characterized in that it comprises means for controlling the reversal of the direction of rotation of the pneumatic motor (12) comprising a pallet (30) cooperating with a compressed air distribution wall (36) and connected to a pusher (6) movable against the action of elastic means (24) and located outside the body (1) so that, when not stressed, the motor (12) rotates in the normal direction, while when it is pushed against the action of the elastic means (24), it controls the reversal of the direction of rotation of the motor.

Description

Improved pneumatic screwdriver The present invention relates to a

  pneumatic screwdriver. The present invention relates to

  screwdrivers having an elongated body with, at one end

  mite, a compressed air inlet and, at the other end, a head intended to receive a screwing tool, the

  body with an articulated trigger intended to

  switch on the compressed air intake to control a

pneumatic motor.

  When the trigger is pressed, the compressed air being admitted, the motor drives the head to allow screwing. It has happened that this is not carried out correctly and it is necessary, in

  in this case, unscrew. The screwdrivers include

  generally try to control reversal

  the direction of rotation of the motor, but this is relatively

tively complex.

  One of the aims of the present invention is to provide a practical, reliable reversing system

  and less complex than those of the prior art.

  The screwdriver, according to the invention, is of the type comprising a body with, at one end, means for the connection of a compressed air inlet pipe, a pneumatic motor driving, by a kinematic connection, a tool located at the other end, a movable trigger on the body and controlling, through an intake opening of a wall for distributing compressed air, the intake to the engine, said wall comprising an exhaust opening connected by leads to an exhaust of the screwdriver and of means for controlling the reversal of the direction of rotation of the pneumatic motor, said screw driver being characterized in that said means for controlling the reversal of the direction of rotation of the pneumatic motor comprise a cooperating pallet with the wall for distributing compressed air and connected to a movable pusher against the action of elastic means and situated outside the body in the vicinity of the trigger so that, when it is not so llicity, the engine rotates in the normal sense, while when it is pushed against the action of elastic means, it controls the reversal of the direction of rotation of the engine, the distribution wall comprising a second intake opening for reversing the direction of rotation of the engine, the pallet being pierced with a conduit in communication with the compressed air inlet and opening on the distribution wall opposite the intake opening, while when the pusher is urged against the action of the elastic means, the pallet is moved so that its duct is disposed opposite the second opening, said intake openings being in communication with the exhaust ducts so that, when one

  is in communication with the compressed air, the other cons-

tituates a secondary exhaust.

  According to a constructive characteristic, the pusher is integral with a rod mounted to slide in a bore of the body against the action of a compression spring inserted in said bore, said rod comprising a notch with which cooperates a stud solid with the pallet which is guided, on the one hand, on a shoulder of the distribution wall and, on the other

  hand, in a throat of an element of the body.

  The invention will now be described.

  in more detail by referring to a mode of realization

  particular position given by way of example only and shown in the accompanying drawings, in which: Figure 1 is an elevational view of a

screwdriver according to the invention.

  Figure 2 is an enlarged sectional view of the rear end of the screwdriver of the

figure 1.

  Figure 3 is a sectional view along the

line 3-3 of figure 2.

  Figure 4 is a sectional view similar to Figure 3, the screwdriver being controlled for a

left rotation.

  Figure 5 is a schematic view of the

  command to change the direction of rotation of the motor.

  Figure 6 is a sectional view along the

line 6-6 of Figure 5.

  Figure 7 is a sectional view along the

line 7-7 of figure 5.

  Figure 8 is a schematic view of the control of the change of direction of rotation of the motor, it occupying a position for rotation at

left of said engine.

  Figure 9 is a sectional view along the

line 9-9 of figure 8.

  The screwdriver shown in the figures comprises a body 1 with, at one end, means 3 for receiving a tool and, at the other end, a nozzle 2

  intended to receive a compressed air inlet pipe.

  On the body 1 is articulated, on an axis 4,

control trigger 5.

  Movable on the body 1 is a push-button 6 for controlling the change in the direction of rotation of a

air motor 12.

  The end piece 2 is pierced with a conduit 7 in which is wedged a ring 10 on which is supported

  one end of a spring 8, the other end of which

  moth cooperates with ball 9 of a valve bearing on

  a seat 14. The body 1 is provided with a trans-

  versal 17 in which a finger 16 slides, one end of which is capable of pushing the ball 9 for opening the valve, while the other end bears against the trigger 5, a seal 18

  being mounted on the finger and being held by a shoulder

19.

  Behind the seat 14, there is provided a channel 20 formed in an element 32 of the body 1 and

  which opens into an opening 33 of a pallet 30.

  The pusher 6 (see Figures 3 and 4) comprises a rod 22 slidably mounted in a bore 23 of the element 32 against the action of a compression spring 24 bearing on the bottom of said bore and said rod 22 is provided with 'a throat 25 in

which is inserted a seal 26.

  The rod 22, at an intermediate point of its length, comprises a notch 28 in which is engaged a stud 29 integral with the pallet 30 which, at one end, is guided on a shoulder 31 of a wall 36 for distribution and exhaust and to the next

  end, in a groove 45 of the element 32.

  The pallet 30 is pierced with a channel 34

  opening at one end, on the one hand, and into the

verture 33, on the other hand.

  In the wall 36 is made an exhaust opening 41 and, diametrically opposite, two openings 39 and 40 which allow, the first, the admission for the rotation of the motor 12 in the normal direction (rotation to the right), while the other generates admission for the opposite direction of rotation (rotation

to the left).

  The two openings 39 and 40 open

  on a conduit 44 formed in element 32 and common

  connecting with a conduit 43 opening onto a rear end of the body 1 provided with exhaust openings 15

  with interposition of noise reducing washers 21.

  The element 32 is pierced with a conduit 42

  in communication with the opening 41 and the conduit 43.

  As seen in Figures 5 and 8, the pallet 30 is capable of selectively communicating the opening 40 with the admission of compressed air through the channel 20, the opening 33 and the channel 34

  or opening 39 through the same elements.

  In normal operation, the trigger 5 is pressed so that the finger 16 releases the ball 9 from its seat 14, the compressed air supplying the engine 12 through the opening 40, while the main exhaust is effected by the opening 41, the conduit 42, the conduit 43, through the washers 21 and the openings 15, and the secondary exhaust through the opening 39, the

  conduit 44, conduit 43 and the openings 15.

  If the user needs to do one. unscrewing, it presses the pusher 6 which, by its notch 28, drives the stud 29 so that the pallet 30 (see FIGS. 8 and 9) pivots, the opening 39 then being fed through the channel 34; the main exhaust takes place in the same way as when the engine is supplied for the normal direction of rotation, while the secondary exhaust takes place through the opening 40, the duct 44,

the conduit 43 and the openings 15.

  As soon as the pusher 6 is released, the

  lette 30, with the action of spring 24, returns in

its initial position.

  Of course, the invention is not limited

  to the embodiment which has just been described and represented

  smelled. We can make many modifications

  detail without departing from the scope of the invention.

Claims (2)

R E V E N D I C A T I 0 N S   1. Pneumatic screwdriver of the type comprising a body (1) with, at one end, means (2) for the connection of a compressed air inlet pipe, a pneumatic motor (12) driving, by a kinematic connection, a tool located at the other end, a trigger (5) movable on the body (1) and controlling, through an inlet opening (40) of a compressed air distribution wall (36) , admission to   motor, said wall comprising an exhaust opening   pement (41) connected by conduits (42, 43) to an exhaust   pement (15) of the screwdriver and means for controlling the reversal of the direction of rotation of the pneumatic motor, characterized in that said means for controlling the reversal of the direction of rotation of the pneumatic motor (12) comprise a pallet ( 30) cooperating with the compressed air distribution wall (36) and connected to a pusher (6) movable against the action of elastic means (24) and located outside the body (1) in the vicinity of the trigger (5) so that, when it is not stressed, the motor (12) rotates in the normal direction, while when it is pushed against   the action of the elastic means (24), it controls the inversion   direction of rotation of the motor (12), the distribution wall (36) comprising a second intake opening (40) for reversing the direction of rotation of the motor (12), the pallet (30) being pierced with 'a conduit (34) in communication with the compressed air inlet and opening on the distribution wall opposite the intake opening (40), while when the pusher (6) is pressed against the action of the elastic means (24), the pallet (30) is moved so that its duct (34) is disposed opposite the second opening (39), said intake openings (39, 40) being in communication with the exhaust ducts (42, 43) so that, when one is in communication with the compressed air, the other   is a secondary exhaust.   2. Pneumatic screwdriver, according to claim 1, characterized in that the plunger (6) is integral with a rod (22) slidably mounted in a bore (23) of the body against the action of a compression spring (24 ) inserted into said bore, said rod comprising a notch (28) with which cooperates a stud (29) integral with the pallet (30) which is guided, on the one hand, on a shoulder (31) of the distribution wall ( 36) and, on the other hand, in a   groove (45) of an element (32) of the body (1).