FR2558567A1 - Device for the dual mechanical control of a switch, and machine comprising its application. - Google Patents

Abstract

This device comprises two triggers 18, 28 acting on two end portions A, 23 of a floating part 17 which is able to pivot about each of its ends, and driving, via an intermediate portion B, the actuation of a switch 16. Only the combined actuation of the two triggers 18, 28 allows a motor 6 to be put into operation, the release of any one of the two putting the machine in a braking position.

Description

 The invention relates to double mechanical safety control devices, and to machines, in particular hedge shears, with application thereof.

 Certain portable machines in which an electric motor. for example, drives a dangerous and / or delicate handling tool must be held with two hands to be controlled and so that the user cannot approach the moving tool with one hand while the machine is running. These machines therefore have two independent controls, one for each hand to keep the tool running.

 Releasing any of the controls should cause the tool to stop as quickly as possible, and preferably by a braking action.

A first object of the invention is therefore to provide a practical and economical dual control device for a machine, and in particular for a hedge shear,
This object is achieved thanks to a safety control device for a machine comprising an on-off control member associated with two actuating members provided at separate locations of the machine and having to be actuated by both hands at the same time. of a user characterized in that the two actuating members are mechanically connected to said on-off control member by means of a floating intermediate piece which is intended to cause the actuation of this control member in two separate half-strokes, the first of which can be obtained by one or other of the actuating members and the whole of which can only be obtained by the two actuating members at the same time.

 Another object of the invention is to provide a double safety control device for an electric motor machine which provides a braking action when any of the controls is released.

 This object is achieved by means of a device as described above, characterized in that the start-stop control member comprises an inverter mounted so as to short-circuit said electric motor in its position rest and to authorize the supply thereof in its active position which is obtained only after completion of the entire stroke of the floating part.

 In this way. the release of any of the controls stops the supply of the motor, and the latter being furthermore short-struc- tural, it is braked by electromagnetic auto-induction.

Other characteristics and advantages of the invention will appear better on reading the description which follows, given with reference to the appended drawings, given by way of example and in which:
- Fig.1 is a longitudinal section along line 1-1 of Fig.2, a hedge trimmer equipped with a device according to the invention;
- Fig.2 is a section along line 2-2 of Fig.t;
- Fig.3 shows in section a detail of the dual control device:
- Fig.4 shows in section along line 4-4 of Fig.1 a part of the dual control device;
- Fig.5 is an enlarged view of part of the device of Fig.1;
- Figs. 6, 7 and 8 show in section a part of the dual control device in different positions of use;
- Fig.S is a partial sectional view of a variant of the invention;
- Fig.10 is a diagram of the electrical wiring of the machine.

A hedge trimmer is partially shown in Figs. 1 and 2. It conventionally comprises two conjugate blades 1 and 2 adapted to slide longitudinally 1 one over the other between two counterblades 3 and 4, teeth la and 2a (FIG. 2) carried by the protruding blades on the edge of the counterblades,
The rear part of the blades 1 and 2 is slidably mounted at the front of a casing 5 containing a motor 6 connected to the blades by drive means.

 The casing 5 extends in the rear extension of the blades and its lower, flat wall is parallel to the plane of the blades and adjacent to this plane.

 The front part 5a of the casing is long and narrow, and its upper face, inclined, supports a front handle 7 and a transparent protective plate 8 interposed between the blades and the front handle.

 The wider middle part 5b contains the drive means which include an electric motor 6 mounted vertically and a reduction gear 9 rotatably mounted on a fixed shaft 10. The wheel 11 of the gear 9 carries two crank pins 12 connected to the blades by connecting rods 13.

 The rear part 5c includes an oval opening 14 delimiting another handle of the machine.

A passage is provided on the rear end wall of the casing 5 for a power cord 15 connected to the motor 6 via an inverter 16 located at the front of the rear part 5c and which may be of the SR type 302 manufactured by the KAUT Company and
BUX, Federal Germany,
The reverser 16 comprises a box 16a fixed to the casing 5 and a slide 16b biased towards the outside by a not shown return spring which is located in the case of the reverser.

 The electrical wiring of 1 inverter 16 is shown schematically in Fig.tO. In the rest position of this inverter, that is to say when the slide 16b is pushed out of the housing 16é as shown in this Figure, the armature 61 of the motor 6 is short-circuited with an inductor 8t, of so that the rotation of the armature generates counter-electromotive braking forces. Preferably, only one inductor is used for this, so as to avoid too sudden braking. Conversely, in the active position of the inverter 16, the slide 16b being pressed into the housing, the movable contactors 16c move together so that the armature 6 is connected in series between the inductors 6q and Sc connected to the sector, which therefore causes the motor to rotate.

 The slide 169. of rectangular section.

is in contact by its rear face with a floating piece 17 extending vertically and received in a U-shaped groove delimited by a first actuating member or rear trigger 18.

 The trigger 18 comprises a first branch 18a penetrating approximately orthogonally into the handle 5c, and slightly inclined towards the rear of the machine, and a second branch 18b projecting into the opening 14 and extending approximately horizontally in a slot 5d provided on the underside of the rear part 5c.

 The branch 18a is articulated around a pin 19 fixed transversely in the rear part 5c. and passing through two legs 20 projecting forward at the upper end of the trigger 18, while its lower branch 18b is adapted to move in the slot 5e of the handle, and abuts at rest against the rear edge of this slot . A lug 21 projecting rearward and centered on the axis of the pin 19 tangents the rear edge of this slot in order to ensure constant closing. On the other hand, when the branch 18a pivots forward, the wings of the branch 18b overlap the switch 16.

 The floating part 17 is in contact with the trigger 18 by an edge A close to its lower end, the rest of its rear edge being, as shown in FIG. 1, spaced from the core of the branch 18a.

Preferably, in the vicinity of edge A, the part 17 is rounded, in order to facilitate the relative sliding and pivoting of the two parts.

 The rear face of the slide 16b is in contact with another edge B formed on the front face of the part 17.

 A pin 19 passes through a slot 22 in the form of a buttonhole formed in the upper part of the floating part 17.

 In front of the light 22. the floating part comprises a tab 23 to which the rear end of a rod or rod 24 is articulated extending towards the front of the machine bypassing the motor 6, as shown in FIG .2 The front end of the link 24 is bent and has a transverse arm 25 located in the vicinity of the front handle 7.

 The rod 24 is supported by longitudinal guide means (not shown) provided on the casing of the machine, and its transverse parts 241 and 24b (Fig. 2) are slightly spaced from the walls of the casing and from the members it contains, in order to allow forward translational movements.

 The arm 25 is actuated by a bent element 26 which comprises a finger 26ê extending obliquely backwards and upwards, and a connecting part 26k having a threaded orifice whose axis forms with the finger 26a an acute angle .

 The finger 26a is adapted to slide on the rear face of the arm 25, oriented parallel to it.

Part 26b is connected by a screw 27 to a second actuating member 28 in the general shape of a trapezoid housed in the front handle 7 in a manner described below.

 An opening 29 provided at the base of the handle 7 allows the element 26 to move in translation along the axis of the handle, and to partially penetrate it.

 Referring to Figs. 1 and A, it can be seen that the handle 7 has a hollow outer frame 7e of roughly square cross section and which on its two lateral sides and its upper side is provided with a slot 7t formed in the corresponding interior walls of this frame. In the latter is slidably mounted, the second actuating member or second trigger 28 of the machine.

 This is also in the form of a frame and has a roughly rectangular cross section, which is full and of dimensions such that a comfortable sliding in the frame 7a can take place. We can see in Fig.4 that in the areas of the sides of the frame 7a, the trigger extends beyond the slot 7b inward to provide a grip in the hand of a user.

 The lower wall of the frame 7a is provided with a passage 29 through which the bent element 26 which is fixed at this location to the lower side of the trigger 28 by means of the screw 27.

 The axis of the opening 29 is situated approximately in the vertical plane of symmetry of the handle 7, and a cavity 30 centered on the opening 29 is formed in the lower side of the trigger 28. This cavity is intended mounting a spring 31 whose opposite end bears on the upper wall of the corresponding side of the frame 7a. In this way, the bent element 26 is permanently biased downwards by the spring 31.

 The trigger 28 has, outside its lower angles, two respective rounded recesses 32 forming a bearing surface against articulation pivots 33. In other words, the trigger, apart from being able to move in translation relative to the plane of symmetry of the handle 7, can also tilt relative to this same plane in both directions by oscillating on one or the other of the pivots 33. Thanks to this arrangement, the trigger can be actuated by the user on three sides of the frame 7 a while moving the element 26 in the direction of the axis of the handle 7.

 When taking the rear handle 5 with one hand, inserting the fingers into the opening 14, finger pressure on the branch 18k of the rear trigger makes it pivot around the spindle 19. The consecutive rotation of the branch 18 moves edge A forward. and therefore edge B and the slide. However, the action of the return spring of the inverter biasing the latter backwards, the upper part of the floating part 17 remains in the rear position, with the front edge of the light 22 pressed against the pin 19 (Fig. 6).

 In other words, the action of the rear trigger alone has the effect of pivoting the floating clamp 17 around its upper part, the displacement of its intermediate part being reduced relative to the displacement of its lower part.

 Similarly, when taking the front handle 7 with the other hand, either by one of the lateral branches of the frame 7a, or by its upper branch, the pressure of the fingers on the trigger 28 has the effect of drive element 26 upwards, finger 26â slides on arm 25, driving it forward, and with it rod 24, as shown in phantom in Fig.l.

 The latter then drives the tab 23 and therefore the part 17 forwards, until the rear edge of the buttonhole 22 abuts against the pin 19.

As the inverter spring 16 pushes piece 17 backwards at 8, it pivots around the point
A, the displacement of point B is therefore reduced compared to that of the upper part and the slide 16b is only partially depressed (Fig. 7).

If now, the machine is held with two hands each taking a handle, the combined action of the rear 18 and front triggers 26 causes the lower and upper parts of the floating part 17 forward and the displacement of the intermediate part covers the entire possible stroke of the slide 16b (Fig, 8)
The loosening of any of the handles brings back to the situations of Figs. 6 and 7, due to the action of the return spring of 1 inverter 16.

 This inverter 16 has two positions, one, the "on" position, is obtained when the slide 16k is fully depressed and supplies the motor 6. The other, or "braking" position, short-circuits the motor 6 and inducing electromagnetic braking, is obtained in all the other positions of the slide 16b.

In this way, the machine is only in operation when the two triggers are actuated, so when it is held in both hands, As soon as one hand is released, the controls switch in the braking position,
This type of operation therefore entails the use of an inverter provided with a slide having a relatively long stroke. with a movable contact capable of ensuring the short-circuiting of the motor during part of its travel and of producing an inversion only at the end of the travel.

 This complication can be avoided very simply, and use a short-type inverter of the current type such as that mentioned previously.

thanks to the particular arrangement of the alternative embodiment shown in Fig. 9. on which the constituent elements identical to those of the embodiment described above are designated by the same references.

 In this variant, the inverter 16 is slightly moved away from the floating part 17, while a trigger spring 34 is fixed to the handle 5c and biases the trigger 18 towards its relaxed position via the lug 21 for example, provided with a teton 35 for this purpose.

 The first half-stroke of the floating part 17, due to the actuation of one or the other of the control triggers 18 or 28 has here the effect of bringing the edge B into contact with the slide 16q, without the move. Only the second half-stroke allows the slide to be pushed in and thus actuates the reverser 16. The wiring being as described in connection with FIG. 10, a double safety command with automatic braking is therefore obtained by using a short stroke reverser.

 It is clear that one can easily imagine a large number of other variants of arrangement of the inverter 16 allowing a double start-up command with automatic electric braking, adapted to the mechanical dual control device of the invention. . For example, the trigger spring 34 can be disposed between the trigger 18 and the inverter 16, or it can be placed between the edge B and the slide 16b.

Claims (15)

 1. Safety control device for a machine comprising an on-off control member (16) associated with two actuating members 118, 28) provided at separate places of the machine and having to be actuated by both hands both of a user, characterized in that the two actuating members (18.28) are mechanically connected to said on-off control member (16) by means of a floating intermediate part S17) which is intended to cause the actuation of this control member <16) in two separate half-courses, the first of which can be obtained by one or other of the actuating members and all of which can only be obtained by the two actuation at a time.  2. Device according to claim 1. characterized in that said floating part <17) is mounted articulated about an axis (19) fixed to the machine while being able to move in translation relative to this axis.  3. Device according to any one of claims 1 and 2 wherein said on-off control member is an on-off electric switch (16) comprising a control slide (16b) movable between an on position and a stop position at against the action of an elastic member characterized in that said floating part (17) has on the one hand an edge (B) intended to cooperate with said slide (16b) and on the other hand portions (A, 23) of cooperation with said actuating members (18,28).  4. Device according to claim 3. characterized in that the edge (B) is supported pe manent with the slide (16b), so that the floating part (17) transmits to the actuating members (18,28) the restoring force of said elastic member.  5. Device according to claim 3, characterized in that the edge (B) of cooperation of the floating part (17) is in contact with the slide (16b) only when it has performed at least half a stroke under the action of any of the actuating members (18,28), trigger springs (31,34) being provided for the return of the actuating members to their rest positions.  6. Device according to one of claims 3 to 5, characterized in that a first of said cooperating portions of said control part (17) is a corner portion (A) in direct abutment against a first of said members actuation (18) and in that a second of said cooperation portions is formed by an articulation tab 123) of a rod (24> by means of which the articulation tab (23) is connected remotely to the second actuator (28).  7. Device according to claim 2 taken together with any one of claims 3 to 6, characterized in that the first actuating organ is in the form of a trigger 1183 articulated on said fixed axis (19) on which said floating is mounted floating part (17).  8. Device according to claim 7, characterized in that said trigger (18) has the shape of an L with a cross section in gutter in which is guided laterally said floating part (17), one of the branches of trigger l18b ) projecting from the housing (5) of the machine in an opening (14) delimiting in this housing a first handle (5s), said fixed axis (19) passing through the free end of the other branch (19a) passing in an elongated lumen (22) formed in said floating part (17) and the length of one of its half-courses.  9. Device according to any one of claims 2 to 8 wherein said other actuating member (28) is housed in a holding handle (7) of the machine, characterized in that said handle (7) comprises a frame fixed (7a) and a movable frame (28) slidably mounted against an elastic return member (31) in the fixed frame (7a) and being able to move in the general plane thereof, said movable frame (28) comprising normally projecting portions of the frame (7a) to allow its control by a user.  10. Device according to claim 9, taken together with any one of claims 6 to 8, characterized in that said movable frame (28) is connected to said floating part (17) via said rod (24) .  11. Device according to any one of claims 9 and 10, characterized in that said handle (7) in the form of a frame also comprises means (33) intended to allow tilting of the movable frame in the fixed frame (7) in the general plan of it.  12. Device according to claim t1, characterized in that said tilting means comprise, arranged in two contiguous angles of the fixed frame, cylindrical pivots (33) cooperating with recesses with cylindrical surface (32) bearing respectively against these pivots.  13. Device according to any one of the preceding claims, characterized in that it is incorporated in a hedge shear comprising an electric drive motor (6) controlled by said on-off control member (16)  14. Device according to claim 13, characterized in that said on-off control member (16) comprises an inverter mounted so as to short-circuit said electric motor (16) in its rest position and to authorize the power supply. - Action of the latter in its active position which is only obtained after completion of the entire stroke of the floating part (17).  15. Portable machine driven by an electric motor and comprising two handles, ca ractêrisée in that it comprises a safety control device according to any one of claims 1 to 10.