FR2528929A1 - IMPROVEMENTS IN MECHANICAL DEVICES FOR SELECTIVE DRIVING OF AT LEAST TWO SHAFTS DRIVEN FROM A SINGLE DRIVING SHAFT, IN PARTICULAR FOR THE LONGITUDINAL MOVEMENT OF AN INK RIBBON IN A PRINTING MACHINE - Google Patents

Abstract

MECHANICAL DEVICE FOR SELECTIVE DRIVING OF AT LEAST TWO DRIVEN SHAFTS 6, 8 INCLUDING A SATELLITE WITH TWO COOPERATING WHEELS 2, 3 OF WHICH ONE 2 IS DRIVEN AND TWO WHEELS DRIVEN 5, 7 WEDDED ON SHAFTS 6, 8 AND AGENCY FOR SUBJECT LOCAL RADIAL ELASTIC DEFORMATIONS, THESE TWO WHEELS BEING SITUATED AT EQUAL DISTANCE FROM AXIS 1 OF THE DRIVING WHEEL, A DISTANCE WHICH IS LESS THAN THE SUM OF THE DIAMETER OF SATELLITE WHEEL 3 AND OF THE RADIUS OF DRIVING WHEEL 2.

Description

Improvements made to mechanical drive devices

  selective of at least two trees led to

  Start from a single leading tree, especially for moving

  Longitudinal cementing of an ink ribbon in a printing machine The present invention relates to improvements

  supplied to mechanical drive devices

  reading of at least two driven shafts, from a single driving shaft, comprising a driving shaft driving a driving wheel, a satellite wheel permanently driven by this driving wheel and mounted idly on a support which can rotate freely around the 'axis of the driving wheel,

  a first driven wheel, integral in rotation with the first

  mier driven shaft and with which the satellite wheel can come into gear,

  a second driven wheel, integral in rotation with the second-

  me driven shaft, and with which the satellite wheel can engage, 15 _ the axes of the driving wheel, the satellite wheel and

  two driven wheels being parallel.

  Devices of the kind under consideration find application

  particularly advantageous, but not exclusive, cation for longitudinally moving an ink ribbon in a printing machine such as for example a typewriter, teletype, computer printer, etc. In a known device, the driving wheel and the satellite wheel associated with it are carried by an independent support capable of moving elastically

  transversely to the driven wheels

  transverse support occurs during an increase

  tation of the resistant torque produced by the driven wheel (for example end of the ink ribbon or blocking of the ribbon) and the satellite wheel can then disengage from the driven wheel with which it previously cooperated, pivot around the axis

  of the driving wheel and come to cooperate with the other me-

  born, for example to reverse the direction of travel of the

ink ribbon.

  In this known device, the fact that the support of the driving wheel must be able to move transversely leads to positioning said support on the c 8 tee of the chassis supporting the driven wheels and the members associated therewith, thereby increasing the size. of the device It also follows that the escape strokes of the satellite wheel are not exactly the same depending on whether it passes from the first driven wheel to the second driven wheel or vice versa: this results in different response times which can be a disadvantage in

certain conditions of use.

  In addition, the transverse travel of the support does not

  Do not worry that the drive of the driving shaft can be done by a classic cable system and it is

  necessary to provide a specific geared motor.

  As a result, the weight of the device then becomes significant and the carriage of the printing machine which

  is thus equipped has too great an inertia.

  Finally, the cost of such a device is too

  high, in particular because of the presence of the motoreduc-

  tor which, before being reliable, is relatively expensive.

  The object of the invention is essentially to remedy

  to the above disadvantages and to realize a dis-

  positive compact, light, with few parts, reliable, able to be entered by cables in a conventional manner, and inexpensive so that it can be incorporated into

  Relative price wide circulation printing machines

moderately low.

  For these purposes, the device of the invention is characterized

  due to the fact that: these two driven wheels are arranged so as to be able to undergo local radial elastic deformations, and these two driven wheels are arranged at equal distance

  the axis of the driving wheel, this distance being less than

  less than the sum of the diameter of the satellite wheel and the

  radius of the driving wheel, with a corresponding value

  due to the possibility of radial deformation of each

of the above two driven wheels.

  Thanks to this arrangement, when one of the two driven shafts is blocked, the satellite wheel bears on the

  corresponding driven wheel, causes its elastic deformation

  that radial and, rolling on its circumference, manages to escape its contact, which then allows the support of this satellite wheel to move angularly until the satellite wheel comes into engagement with the other wheel driven for the drive in rotation and thus drive the other driven shaft, the whole of this process can then be

  repeat when this other driven shaft is itself blocked.

  As a result, the torque of the driving wheels and its

  tellite can be accommodated in the free space separating the two driven wheels, the axis of the driving wheel being able by

  example be aligned with the two shafts of the driven wheels.

  The mechanical structure thus formed is relatively compact, with no cantilevered parts or members, comprises a minimum number of component parts and is therefore of a

  weight and minimum inertia compatible with the

  gences required for certain applications such as

  the equipment of a printer machine cart.

  In a preferred embodiment, each wheel

  -near comprises a rigid or substantially rigid rim and hub joined together by connecting means

  radially elastically deformable.

  It is then possible to ensure that the means

  connecting means include several radially arranged springs

  slightly and angularly equidistant from each other,

  these springs can for example be helical springs

  coldaux or long bendable raises of

elastic way.

  However, for simpler mounting and less

  production cost, the aforesaid connecting means comprising

  advantageously a continuous annular web, interposed between hub and rim, made of a material having elastic deformation properties at least according to

radial directions.

  In either case, the wheel as well

  can be easily made in one piece

  this by using material molding techniques

synthetic res.

  The driving, satellite and driven wheels are toothed wheels and / or friction wheels. A particularly preferred, although not exclusive, application of the mechanical drive device

  the invention resides in a device for moving longi-

  tudinally an ink ribbon from a printing machine

  such as typewriter, teletype, computer printer

  teur, etc, the two driven wheels then cooperating respec-

  rotatably with two support plates for the

  inking rolls of the ink ribbon.

  An automatic reversing device is thus obtained.

  as the direction of travel of the ink ribbon, in particular at the end of the ribbon or in the event of jamming of the ribbon, also having the ability to skate (escape of the satellite wheel alternately on the two driven wheels) in the event of complete blocking (in the two scrolling directions

ribbon).

  This gives the device for moving the ru-

  ban the advantages of tape cassettes

  crying while keeping standardized rolls of tape

  to which many users wish to remain loyal

  them especially because of their lower price.

  In this context, it is possible to ensure that this device is disposed on the movable carriage of the printing machine and that the driving shaft cooperates with cable drive means known per se, comprising

  two freewheels mounted on the drive shaft and two

  parallel drive wheels coiled around respectively

of the two free wheels.

  This eliminates the previous solution, which is too expensive, of training using a geared motor, and it is

  possible to make a technologically simple device

  full and inexpensive, but particularly effective in

  its applications more specifically envisaged.

  The invention will be better understood on reading the

  description which follows of a preferred embodiment gives

  born only as an illustrative example; in this

  description, reference is made to the accompanying drawings in the-

  which s Figures 1 to 3 show a mechanical device

  drive arranged in accordance with the invention,

  pectively in three different functional positions

  FIG. 4 represents a device for driving an ink ribbon of a printing machine arranged in accordance with the invention,

  Figure 5 is a schematic side view of the device

  tif of Figure 4 with a drive by two parallel cables, and Figure 6 is a bottom view of part of the

figure 5.

  Referring firstly to FIG. 1, a driving shaft 1 drives a driving wheel 2: for example, as shown, the wheel 2 is wedged on the shaft 1 A satellite wheel 3 cooperates permanently with the driving wheel 2 and is driven in parmanence by it; the wheel 3 is mounted idly on a support 4 (constituted for example

  by two lateral flanges) which can rotate freely

driving wheel axle 2.

  Furthermore, there is provided a first driven wheel 5 integral in rotation with a first driven shaft 6 (the wheel 5

  can for example be wedged on the shaft 6) and with which

  the satellite wheel 3 can come into engagement A second driven wheel 7 is integral in rotation with a second driven shaft 8 (for example by being wedged on the shaft 8) and the satellite wheel 3 can come into engagement with the second wheel

conducted 7.

  It will be noted that the axes of the driving wheel 2, of the

  satellite wheel 3 and two driven wheels 5 and 7 are

  parallel to each other and substantially perpendicular to a support plate 9, all the wheels being substantially coplanar. The two driven wheels 5, 7 are arranged at equal distance from the axis of the driving wheel 2, this distance

  being less than the sum of the diameter of the satellite wheel

  lite 3 and the radius of the driving wheel 2.

  In addition, the two driven wheels 5 and 7 are arranged to be able to undergo local radial elastic deformations; in other words, they are arranged so

  that their respective axes remain fixed but that their

  ripheria can deform, or move, radially

locally.

  Advantageously, each wheel 5, 7 has a hub

  rigid respectively 10, 11, a rigid or sensitive rim

  rigidly respectively 12, 13, and connecting means respectively 14, 15 interposed between the rim and the hub, these connecting means being able to undergo radial elastic deformations, The elastic means 14, 15 can for example be constituted by radial helical springs, in particular three springs arranged at 1200 as shown It can

  they are also springs made up of masses of elas-

  tomère It can also be bent spokes curable longitudinally. However, in practical terms, the connecting means 14, 15 consist of a continuous web made of a material which is strong enough to ensure the connection

  mechanical from rim 12, 13 to hub 10, 11, but present

  both elastic deformation properties at least in radial directions For example, the wheel can be manufactured by double injection molding, the web being made of rubber, polyurethane, etc,

  and the plastic hub and rim.

  Of course, in the case where the material chosen will be a moldable synthetic material, the whole of the wheel (hub, rim and connection means) can be manufactured in one piece by molding, that the connection means are constituted by the above mentioned reasons or by a

continuous veil.

  Although the arrangement which has just been described seems to

  ble must be the most interesting both from the manufacturing point of view and from the use point of view, we do not however exclude other solutions such as

  example a locally deformable rim in a direction

  diale. The wheels used can be of any type suitable for the proper transmission of

  torques These can be cogwheels, overwheels

  smooth face having a large coefficient of friction, wheels with grooved surface or any combination of such wheels, The operation of the device of the invention is as follows,

  The driving shaft 1 drives the driving wheel 2 for example-

  ple in the dextrorotatory direction and itself drives the satellite wheel 3 in the senestrogyre direction, Under the action of the reaction torque, the support 4 tends to rotate in the dextrorotary dens around the axis of the wheel 2 on which it is articulated and therefore, in normal operation, the satellite wheel 3 remains applied in engagement against the driven wheel 5 Taking into account the previously mentioned distance ratios between the different wheels, and the fact that

  the reaction force now the satellite wheel 3 applied

  quée against the driven wheel 5 is less than the radial deformation force of the means 14, it follows that the device is in the stable position shown in the

  Figure 1, the wheel 5 being driven in the direction dextrogy-

  re. If the resisting torque increases for any reason (for example braking or blocking of the driven wheel 5), the reaction torque which keeps the satellite wheel 3 in abutment against the driven wheel 5 increases and,

  when the effort thus generated becomes greater than the ef-

  strong radial elastic connecting means 14, the wheel

  satellite 3 pushes the Rim 12 of the driven wheel 5 di-

  rection of the hub 10 against the elastic forces ra -

  dials exerted by the connecting means 14 In other words, the hub 10 retains the same axis of rotation (in this case, it remains wedged on the driven shaft 6), but the

  rim 12 is off-center (Figure 2).

  The satellite wheel 3 then escapes contact with the driven wheel 5, then, due to the rotation caused by the reaction torque, pivots around the driving shaft 1 to come into contact with the driven wheel 7 which it drives

  in senestrogyrous rotation (figure 3).

  If, for its part 8, the driven wheel 7 is also blocked

  quée, -the phenomenon of escape is renewed in the same way, and the satellite wheel 3 pivots around the shaft 1

  by alternately pushing the driven wheels 5 and 7.

  The device of the invention is likely to find

  ver many applications among which we retain-

  dra more particularly that relating to the entanglement of the ink ribbons in printing machines such as typewriters, teletypes, computer printers, etc. Such an application is shown diagrammatically in FIGS. 4 to 6 to which we now refer (and to which

  the elements identical to those of FIGS. 1 to 3 are de-

  signed by the same reference numbers).

  The assembly shown in Figures 1 to 3 is completed by an additional drive wheel 16 wedged on the first driven shaft 6 and which is engaged with a wheel 17

  of m 8 me diameter wedged on the shaft of rotation of a pre-

  mier tray 18 supporting one of the coils 19 of the ribbon

inkpad 20.

  On the second driven shaft 8 is wedged a second plate

  21 supporting the other coil 22 of the ribbon 20.

  Brakes 25, cooperating respectively with the

  driven wheels 5 and 7 ensure constant tensioning

aunt of the ribbon 20 (see Figure 4).

  Thanks to this arrangement, the two coils 19 and 22 are selectively driven by the satellite wheel 3,

  in the direct direction (arrow 23) in the case of a drive

  normal (wheel 3 shown in solid lines) or in the

  opposite direction (arrow 24) in the case where the ribbon is

  to move in the normal direction (wheel 3 shown

in dashed line).

  This assembly performs the automatic reversal of the direction of travel of the ribbon, for example at the end of the ribbon or in the event of the ribbon jamming in the normal direction (arrow 23).

  if the ribbon is completely blocked, the satellite wheel

  te 3 turns alone around the shaft 1 without driving the driven wheels 5 and 7.

  The assembly shown in Figures 4 to 6 is particularly

  particularly interesting insofar as it can be ins-

  easily mounted, due to its compactness, on a printing machine carriage In addition, since the drive shaft 1 does not undergo any transverse movement relative to the driven wheels and to the plate, it is not necessary to have recourse to an independent motor device, such as a gear motor; one can carry out the drive of the driving shaft 1 using a classic drive by double c Able and double freewheel, which is commonly used in

printing machines.

  As shown in Figures 5 and 6, two li-

  bres 26 and 27 (with the same drive direction) are set,

  one above the other, on the tree leading 1 A pre-

  mier target 28, connected to first drive means, is wound in the dextrorotatory direction around the free wheel 26 while a second cable 9 ble 29, connected to second drive means, is wound in the senestrogyre direction around the wheel free 27, so that the driving shaft 1 is rotated by one or the other of the wheels

  free 26, 27 while the carriage is moving.

  As goes without saying and as it moreover already follows from the above, the invention is in no way limited to those of its modes of application and embodiments which have been more especially envisaged; she embraces it, at

otherwise, all variants.

Claims (5)

  1 Mechanical device for selective entrainment of at least two driven shafts, from a single driving shaft, comprising: a driving shaft (1) driving a driving wheel (2), a satellite wheel (3) permanently driven by this   driving wheel (2) and idle mounted on a support (4) for   before turning freely around the axis of the drive wheel   te (2), a first driven wheel (5), integral in rotation with the   first driven shaft (6) and with which the satellite wheel   te (3) can engage, a second driven wheel (7) integral in rotation with the   second driven shaft (8), and with which the wheel satel-   lite (3) can engage, the axes of the driving wheel (2), the satellite wheel (3) and the two driven wheels being parallel, characterized in that: these two driven wheels (5, 7) are arranged to   ability to undergo local radial elastic deformations   the, and these two driven wheels (5, 7) are arranged at equal distance from the axis of the driving wheel (2), this distance   being less than the sum of the diameter of the wheel sa-   tellite (3) and the radius of the driving wheel (2), and this   of a value corresponding to the possibility of deformation   radial tion of each of the above two driven wheels (5, 7),   whereby, when one of the two driven shafts is blocked, the satellite wheel bears on the corresponding driven wheel, causes its radial elastic deformation and, by rolling around its circumference, manages to escape its contact, which allows then the support of this satellite wheel to move angularly until the satellite wheel comes into engagement with the other driven wheel to drive it in rotation and thus drive the other driven shaft, the whole of this process can then repeat   when this other driven tree is itself blocked.   2 Mechanical device according to claim 1, characterized in that each driven wheel (5, 7) comprises   a rigid or sensitive rim (12, 13) and a hub (10, 11)   rigidly joined together by means of bonding   sound (14, 15) radially elastically deformable. 3 Mechanical device according to claim 2, characterized in that the aforesaid connecting means (14,) comprise several springs arranged radially and   angularly equidistant from each other.   4 Mechanical device according to claim 2,   characterized in that the above-mentioned connecting means   take a continuous annular web, interposed between hub   and Rim, made of a material with properties   elastic deformation tees at least in directions radial.   Mechanical device according to any one of   claims 1 to 4, characterized in that the wheels   satellite and led nantet are cogwheels and / or friction wheels.   6 Device for longitudinally moving a ru-   ban inking of a printing machine, characterized in that it comprises a mechanical drive device according to   any one of claims 1 to 5, the two wheels   leads (5, 7) cooperating respectively in rotation with two plates (18, 21) for supporting the coils (19, 22) ink ribbon winding.   7 Device according to claim 6, characterized   in that it is arranged on the movable carriage of the machine   printer and in that the drive shaft (1) cooperates with target drive means (26 to 29) per se known, comprising two free wheels (26, 27) mounted on the drive shaft and two parallel targets training (28, 29)   coiled respectively around the two freewheels.