FR2589544A1 - SENSING INVERSION POSITIONING CONTROL MECHANISM HAVING HIGH CINEMATIC FLEXIBILITY - Google Patents

Abstract

THE INVENTION CONCERNS POSITIONING MECHANISMS GIVING IMPORTANT REST. IT RELATES TO A MECHANISM WHICH INCLUDES, AFTER A MOTOR 92 AND A REDUCER 88, A FIRST MECHANISM 30 OF AN ALREADY KNOWN TYPE, INCLUDING ONLY PINIONS AND CONNECTING RODS, AND A SECOND MECANISM OF THE TYPE WITH A 70 CONNECTING AND A CRANK 66. THE ADJUSTMENTS RELATING TO THE TWO MECHANISMS ARE SUCH THAT THE STROKE OF THE OUTPUT MOUNTED AT THE END OF THE ROD 70 MAY HAVE A LONG REST AT THE ENDS OF THE STROKE AND IN THE MIDDLE OF IT. APPLICATION TO PARTS POSITIONING MECHANISMS IN MACHINING MACHINES.

Description

The invention relates to a positioning control mechanism for

  reversal of meaning, having a great kinematic flexibility that allows the realization, from

  rotary input device at a constant speed, the

  extremely long rest periods and / or extremely diverse predetermined kinematic characteristics between

  ends of a race, with different characteristics

  in the race back and in the race in advance.

  In the field of mechanically controlled movements,

  There are many applications in

  which it is desirable that an alternating movement be created from a rotational movement. The necessary conditions are generally fulfilled by the well-known connecting rod and crank mechanism or

  cracked butt. However, these mechanisms have a relative rest

  quickly not suitable in some applications.

  tions. The invention relates to a mechanism which provides reciprocating movement from a rotational movement and wherein the output member remains substantially stationary, i.e. at rest, for a substantial fraction

  of the global cycle, at each end of the

alternative cement.

  Displacements of this type can also be created by cam mechanisms, but these are limited in practice to races of a few tens

  centimeters or less, because, beyond that, they are very costly

  expensive. The invention relates to a mechanism that can be achieved inexpensively by its own nature and

  who can give races of 2 m and more.

  The invention also relates to an inversion mechanism having a rest at each end of its stroke and having a

  additional rest at a predetermined location along.

  of its travel, in a direction of travel, and another additional rest at another predetermined location in the other direction of travel, the rest periods being instant stops or significant reductions

of speed.

  French Patent Application No. 86.12443 filed on September 4, 1986 under the title "Alternative Mechanism for

  long-range dragging "describes a mechanism

  also the aforementioned characteristics but whose kinematic flexibility, although it is very important, is not as great as that which can be obtained according to the invention. The latter gives much longer rest and / or a much greater kinematical flexibility between the ends of the race, than the object mechanism

of this patent application.

  Other features and benefits will emerge

  better of the description which follows, made with reference

in the accompanying drawings in which:

  Figure 1 is a partial side elevation

  schematically in a first embodiment described in U.S. Patent No. 4,075,911; Figure 2 is a plan view of the mechanism of Figure 1; Figure 3 is a schematic side elevation of a well known connecting rod and crank mechanism; Figure 4 is a section on line 4-4 of Figure 3; Figure 5 is a block diagram of the mechanism of Figure 3, useful for determining the equations of the movement of this mechanism;

  FIG. 6 is a diagram showing the definition of

  length and amplitude of rest; Figure 7 is a plan view of the mechanical combination according to the invention;

  Fig. 8 is a side elevation of the arrangement

  Figure 7; FIG. 9 is a graphical representation of

  resting characteristics of the connecting rod mechanism and

  velle, the mechanism of Figures 1 and 2 working in an arrangement with a second and a third harmonic, having very long rest, and the combined mechanism of Figures 7 and 8; Fig. 10 is a graph showing a generic curve of a quiescent characteristic indicative of the behavior of the mechanism of Figs. 1 and 2 when operating with a five-point-of-rest configuration; FIG. 11 is a graph showing a generic curve of a rest characteristic indicating the exit movement obtained according to the invention when the crank is disposed in the mechanism of FIGS. 1 and 2 in such a way that the crank is at its central dead center when the mechanism of Figures 1 and 2 is at the center of the rest, with a configuration to give a rest at five locations; FIG. 12 is a graph showing particular curves of rest characteristics according to the invention, intended to give a rest amplitude of 0.001, using the second and third harmonic; FIG. 13 is a graph showing the speed characteristics obtained according to the invention in the case of the configurations whose rest characteristics are indicated in FIGS. 9 and 12; Fig. 14 is a graph showing the displacement characteristics according to the invention when the crank is mounted on the mechanism of Figs. 1 and 2 with phase angles of 90 and 60; Fig. 15 is a graph showing the displacement characteristics according to the invention when the mechanism of Figs. 1 and 2 has a configuration giving a positioning angle of 90, with a phase angle equal to 0; FIG. 16 is a graph showing the displacement characteristics obtained according to the invention when the mechanism of FIGS. 1 and 2 has a configuration such that it gives a positioning angle of 360 with a phase angle equal to 0, and with use second and third harmonic; Fig. 17 is a graph showing a generic rest characteristic curve corresponding to the behavior of the mechanism of Figs. 1 and 2 when operating with a three-point-of-rest configuration; FIG. 18 is a generic curve of a rest characteristic obtained according to the invention when the crank is disposed in the mechanism of FIGS. 1 and 2 in such a way that it is at the center dead center when the mechanism Figures 1 and 2 are in the center of the rest, with a configuration for giving rest at three locations; FIG. 19 is a graph showing the quiescent characteristics according to the invention when the mechanism of FIGS. 1 and 2 is of a configuration such that it gives a rest at three locations and the phase angle is equal to 0, in the arrangements second and third harmonic; and Fig. 20 is a graph showing the speed characteristics obtained according to the invention with the configurations giving the characteristics

  resting places shown in Figure 19.

  U.S. Patent 4,075,911 discloses a family of mechanisms which can create an intermittent, straight or rotational movement from a spinning motion at a determined constant angular velocity. This document is considered to represent the prior art in the present specification and it is described in this document that it describes several embodiments, for example, those of FIGS. 51, 52, 53, FIGS. 54, 55, 56, FIGS. Figures 57, 58, 59, Figures 60, 61, 62, and Figures 63, 64, 65

  which all give a rotary output movement. More pre-

  Figures 51, 52 and 53 of this document indicate

  the output gear 332 rotates at an angle of 90

  during a determined positioning cycle. This is because the pinion 330 has a pitch diameter equal to one quarter

  332. In accordance with the present invention,

  As described later, the part of the mechanism taken from this document is initially used with a positioning angle of about 180. Such a mechanism is described with reference to Figures 1 and 2 herein. FIGS. 1 and 2 are simplified diagrams of this embodiment, intended to give an output movement of 180 for an accelerated and decelerated cycle of its output shaft. As indicated in FIGS. 1 and 2, this mechanism 30 comprises an input shaft 32 which rotates about an axis A 0, in fixed bearings placed in a housing which is not shown. An eccentric segment 34 mounted on the shaft 32 is concentric to an axis A1 offset by a small distance from the axis Ao. An input gear 36 mounted on the eccentric segment 34 is also concentric with the axis A1. Tangential connecting rods 38 are journalled on the eccentric segment 34. A driving pinion 40 is mounted on a shaft 42 which pivots in the tangential rods 38 and rotates about a movable axis A2; it is driven by the input gear 36 via an intermediate gear 34 which is also journalled on the tangential connecting rods 38. In this case, the ratio of the input gear 36 and the driving gear is exactly equal to 2 / 1, that is to say that the pinion

  input 36 rotates twice per revolution of the driving gear 40.

  An eccentric plate 46 is mounted on the shaft 42 and in turn supports an eccentric pinion 48 which is concentric with a movable axis A3. This eccentric pinion 48 is engaged with an output pinion 50 mounted on an output shaft 52 rotating on a fixed axis A4, in bearings mounted in the not shown casing. The eccentric gear 48 is shown to have half the pitch diameter of the output gear 50, providing a positioning cycle for each 180 rotation of the output gear 50, as described below. The eccentric pinion 48 is retained engaged with the output pinion 50 by a radial rod 54 which journalled on the output shaft 52 and on a straight shaft 56 mounted on

  the eccentric gear 48 which is concentric with the axis A3.

  The operation of the mechanism which is analyzed in the aforementioned document can be described qualitatively and quickly in the following manner. The total movement of the output gear is a superposition of a group

  individual elements, each being analyzed individually.

  as if it were the only element giving

  a movement of the output pinion 50.

  It is assumed temporarily that the axes Ao and A1 coincide and further that the axes A2 and A3 coincide, and it is noted that the mechanism 30 is in fact a simple gear reducer, the output gear 50 rotating at the

  quarter of the angular velocity of the input gear 36.

  The ratio between the output gear 50 and its "eccentric" drive gear 40 is equal to 2/1; this pinion 40 is coupled to the driving gear 48 and rotates with it, with a relative ratio to the input gear 36 which is also equal to 2/1 so that the overall ratio is equal to 4/1. Assuming that the input shaft 32 rotates with a constant angular velocity, the output shaft 52 also rotates with a constant angular velocity but equal to a quarter of

that of the input tree.

  If it is now assumed that the axes A2 and A3 are separated by a certain distance, it is noted that the pinions 40 and 48 rotate around each other, the central axis A3 of the pinion 48 oscillating around the axis A4 since the distance between the axes A3 and A4 is fixed by the connecting rod 54, the axis A2 oscillating axes in coincidence A0 and A1 since the distance between the axes A2 and A1 is fixed by the rods 38. The amplitude of these oscillations is determined by the distance between the axes A2 and A3 and causes an oscillation of the

  sprocket due to the oscillation of the A3 axis and the

  eccentric pin 48 around the axis A4.

  Similarly, when the axis A1 is shifted with respect to the axis Ao and always assuming that the input shaft 32 rotates at a constant angular velocity, we note that the axis A1 rotates around the axis axis A and creates a movement

  at the right end of the connecting rod 38. This is

  then raises another oscillation at the pinion 50, with an amplitude which is determined by the distance between the axes A1 and A0. In addition, this latter oscillation has a frequency equal to twice the oscillation frequency of the output gear due to the difference between the axes A3 and A2 since the input gear 36 rotates with an angular velocity equal to twice of the average angular speed of the driving pinion 40 given the

  ratio of their pitch diameter which is equal to 2/1.

  The final component of the movement of the output gear 50 is created by the oscillation. angular rods 38. When these rods move in space with their straight ends which describe the circular path determined by the axis A1 which rotates about the axis Ao, their left ends oscillate up and down around of the A1 axis being trained

  by the A2 and A3 axes which turn around each other.

  This complexed movement also creates a slight component transmitted to the output gear, this component becoming weaker and weaker as the length of the connecting rods 38 increases. The angular oscillation of the rods 38 causes a slight variation in the projected length of these rods on a basic line passing through the axis A and tangent to the output gear 50, and it is this change in projected length that creates the component As the elongation of the connecting rods 38 reduces their angular excursions for determined displacements of the axes A1 and A2, the variations in the projected length decrease rapidly as the length of the connecting rods increases. The total movement of the output gear 50 is therefore

  created by the superposition of the three

  The main characteristics are summarized as follows: 1. a constant speed determined by the gear ratios,

S89544

  2. a first oscillating component due to the

  axes A2 and A3 around one another, 3. a second oscillation component created

  by the rotation of the axis A1 around the axis A0.

  In addition, a fourth fortuitous component necessarily exists due to the angular excursion of the rods 38 which can be made very weak, when

the length of the connecting rod increases.

  The aforementioned four components give a cyclic variation of the movement of the output pinion 50 and a given cycle is repeated once per revolution of the eccentric pinion 40. Consequently, for a given cycle, the output pinion 50 rotates by an angle represented by the ratio of the pitch diameter of the eccentric gear 48 to that of the output gear 50. For example, for the scale indicated in FIGS. 1 and 2, according to which a pinion 48 has a dimension equal to half that of the pinion 50, the exit movement ends a cycle determined for a 180 movement of the output pinion. 50. If the pinion

  48 was the same size as the pinion 50, a cycle necessary for

  would obviously be a 360 rotation of the pinion

50 output.

  The distance between the axes Ao and A1 is called "eccentricity" E2 while the eccentricity of the axes A2 and A3 is called "eccentricity" E1. The addition of this second eccentricity E2, turning an integer multiple of times at each turn of the eccentricity E1, makes it possible to obtain very different kinematic effects on the rotation of the output shaft 52. The aforementioned patent of the

  United States of America No. 4,075,911 gives mathematical details.

  very advanced on these phenomena.

  The mechanism of Figures 1 and 2, bearing the reference 30, is intended to give a relatively long rest with respect to the rotation of the entry angle, the rest not being a true fixed condition of the output shaft but rather a low amplitude oscillation of the output shaft around the center of this oscillation

9 2589544

  which is determined to be the zero point or origin

  for the measurement of the exit angle.

  While the rotary output embodiment of the aforementioned patent shown in Figs. 51, 52, 53 gives an exit position angle of 90 given the proportions of the pinions 330 and 332, the angle

  the output position of the embodiment

  1 and 2 of the present specification gives an output position angle of 180 as previously described. In addition, in the aforementioned patent, the mechanism of FIGS. 51, 52, 53 represents a chain connection 322 between the member placed on the axis A1 (pinion 324) and the member placed on the axis A2 (pinion 321). ), whereas in the embodiment of FIGS. 1 and 2 of this specification, this connection is represented by an equivalent device comprising gears 36, 44 and 40. This small modification of structure is intended to increase

  the rigidity of the drive device.

  The second known mechanism used in the

  of the invention is a rod and crank mechanism de-

  written in many: books on the fundamentals of kinematics. It is also schematically represented

in Figures 3, 4 and 5.

  In Figures 3 and 4, a shaft 60 rotates an axis A5 and journalled in a frame 62, in a bearing 64, this shaft 60 can be driven by any suitable motor. A crank 66 is attached to the shaft 60 and

  supports, at its outer end, a pin 68 concentric

  than to an axis A6. A connecting rod 70 journalled, at one end, on the crank pin 68 and, at the other end, it is articulated on a slide 72 at a hinge axis 74, bearing the reference A7. The slider 72 is supported by the frame 62 in which it can slide freely along an axis A8 which intersects the axis A5 as

shown in Figure 3.

  FIG. 5 represents a useful diagram for analyzing

  lysis of the kinematic characteristics of the system. The dis-

  tance, measured on the crank 66 between the axes A5 and A6, is called R and the length of the connecting rod, between the axes 68 and 74, is called L. The mechanism is shown in two positions, a basic position shown in phantom solid (corresponding to the top dead center) and a dashed position, after rotation of the crank R from its basic position by an arbitrary angle f. It is easily noted in this diagram that the displacement distance of the slider 72 from its base position when the crank R rotates the angle% from its base position is given by the relation: D = R - L - R cos + L cosa (1) with a = sin-1 (R sin4) (2) L

  Assuming that L has a high value

  port to R and as a result that the angle is small, even

  when it has a maximum value, its cosine is very

  check of 1 so that we get: D a R - R cosR (1 - cos4) (3) This approximate equation corresponds to the displacement characteristics of a crank mechanism

and slide.

  The term "rest", in the accepted meaning in general

  in the kinematic domain and applied to some mechanism

  conque, indicates that the output of this mechanism

  is fixed when its input member continues to move.

  From a theoretical point of view, the output member has a zero motion. Movement of output member controlled by cams often include such a rest, in a known manner. However, there are many applications in practice in which a rest with a perfectly zero displacement is not essential and in which a very weak oscillating movement of the output member

  is acceptable. This situation is called "approximate rest".

  In this specification, it is characterized by a numerical value which gives the maximum amplitude between peaks of the output oscillation, expressed as a fraction of the total travel of the output member of the mechanism. For example, an approximate rest (0, 001) indicates that the output member oscillates, during the determined approximate rest, with a total amplitude equal to

  at 0.001 times the total stroke of the mechanism. This characteristic

  is shown diagrammatically in FIG.

  which also schematically gives the definition of the expres-

  "rest length". Assuming that a mechanism is driven by an input shaft that rotates at a constant angular velocity and that the time required for a given positioning cycle is divided into 360 units, each of these units is defined as being 1 degree

  clock angle. A rest length of a hori-

  For example, a box of 90 represents a cycle in which the output member is an approximate pendnat / 360 rest a quarter of the cycle. Obviously if the tree

  input rotates one turn during a position cycle

  nally, a degree of rotation of the input shaft is equal to one degree of the clock angle, or, when for example the input shaft rotates three revolutions during a positioning cycle, each elementary angle three degrees of rotation of the input shaft corresponds to a degree of the clock angle. In other words, the number of degrees of rotation of the input shaft equal to one degree of clock angle can be determined by dividing the total number of degrees of rotation of the shaft.

  input required for a 360 positioning cycle.

  The invention described herein is a combined or tandem mechanism employing two drive stages, the first stage consisting of a rotary output positioning mechanism of the type described in the aforementioned US Pat. United States No. 4,075,911 and with reference to Figures 1 and 2 herein, having an output position angle of 180 (initially), and the second stage consisting of a crank and crank mechanism of the type described previously. This combination of mechanisms is both original and useful and yields results that can only be determined by detailed analysis

  which must be carried out so that the many characteristics

  which can be obtained with the system are determined. In Figures 7 and 8, the mechanism 30 described above with reference to Figures 1 and 2 is housed in a housing 80 and is mounted on a base 82. His tree

  32 entrance is entrained, through a

  84, by the output shaft 86 of a gear reducer 88 which is also mounted on the base 82. The input shaft of this reducer is itself driven by

  a motor 92 via a coupling 94. Sui-

  Before the desired application, the motor can operate continuously or can be stopped during the rest of the mechanism, using limit switches and conventional electrical circuits. The crank 66 (FIGS. 3, 4 and 5) is directly mounted on the output shaft 52.

  of the mechanism 30, the axes A4 and A5 coinciding.

  Obviously, the shaft 60 and the frame 62 (FIGS. 3 and 4) can be retained and a coupling can be used for connecting the shafts 52 and 60, when this feature appears more convenient. The crankpin 68 of the crank 62 is used to drive the rod 70 during reciprocating movement. The other

  end of the connecting rod 70 is connected to an alternating

  native output which can be a slider as represented

  In FIG. 3, the load is entrained or the connecting rod 70 can be directly connected to the input member of the driven load. Such an input member may be a connecting rod, a bent lever or a slider. In all cases, the exit movement is given by the approximate equation (3) described previously,

  the angle% then being the exit angle of the mechanism 30.

  When comparing rest and others

  characteristics of the mechanism of Figures 1 and 2, the mechanism

  3 to 5 and the combined mechanism of FIGS. 7 and 8, it is convenient to change the scale of the output member of all these systems in such a way that

  that the positioning stroke is determined arbitrarily

  The angle of entry is defined by the clock angle that has a range of 360 when it gives the output stroke equal to 1. With these arbitrary operations scaling or normalization, equation (3) becomes: c DU 0.5 [1 - cos (- (4) in which Du represents the normalized motion of

output and kC the clock angle.

  This change of scale is based on the following reasoning in equation (3). The minimum position is observed when 0 = 0 and D = 0, independently of the value of R. The maximum position is obtained when $ = 180 and D is equal to 2R. Consequently, when R = 12 and = (T-), the maximum value reaches 1 when 4 = 360 and equation (4) is obtained when these values of R and% are carried

in equation (3).

  The output displacement given by equation (4), in the approximate rest region, is given in Table I and is schematically represented by the

REF A curve of Figure 9.

TABLE I

  Standardized movement of a simple crank mechanism close to rest Angle of clock Normalized movement

-20 0.007596

-15 0.004278

-10 0.001903

- 0.000476

0 0

0.000476

0.001903

0.004278

0.007596

  The operation of the mechanism 30, which is analyzed

  in the aforementioned patent, can be described qualitatively -

  and quickly as follows. The total movement of the output gear is a superposition of a group of individual components that are individually analyzed as if they were the only component

  causing the movement of the output gear 50.

  Reference is made to this aforementioned patent which gives the equa-

  generalization of the approximate displacement for the case where the axis A1 rotates around the axis Ao of two turns per revolution of the axes A2 and -A3 around each other, in the form: U = e - E1 sine + E2 sin 20 (5) with U = angular output displacement of the output shaft 52, having a range of 2i units regardless of the positioning angle, e = clock angle in radians, E1 = distance between the axes A2 and A3, expressed as a ratio to the radius of the eccentric pinion 48, E2 = distance between the axes A1 and Ao, also expressed as a ratio with respect to the radius

eccentric pinion 48.

  Likewise, when the axis A1 rotates around the axis Ao of three turns per revolution of the axes A2 and A3, the one around

  on the other hand, the generalized equation of the approximate

  tif, given by the aforementioned patent, is: U = - E1 sine + E2 sin 30 (6) It can be noted, with reference to equations (5) and (6) and mechanism 30 as well as to the aforementioned patent, that, when the axis A1 rotates about the axis Ao of N turns per revolution of the axes A2 and A3 around each other, this characteristic being determined by the ratio of the input gear 36 and the driving gear 40, the generalized equation of the approximate displacement of the output element of the mechanism becomes: U = 0 - E1 sine0 + E2 sin N (7) As indicated previously, the output variable U

  undergoes a change of scale so that it reaches 2w uni

  during a positioning cycle; in addition, the entry angle e is given in radians. The comparison of the output movement of the independent mechanism 30 with that of the connecting rod and crank mechanism, as indicated by the curve REF A of FIG. 9, requires the scaling of the equation (7) in standardized coordinates, the surgery

  being carried out by multiplying the totality of the equa-

  by 1 / 2w and by transforming e into a clock angle C expressed in degrees, using the formula: E =% C

  As a result, equation (7) becomes, in normal coordinates,

  mated: D = - [w1E + sinc + E2 sin NC] (8) DU = E-1 sin E21N41cl which simplifies in the form:

C E1 E2

  From the above-mentioned patent, it was stated that the longest rest without inversion, when N = 3, was obtained for F1 = 1.125 and F2 = 0. , 04167 (1/24). Using these values in equation (9) gives the values

  normalized displacement for the various clock angles.

TABLE II

  Clock angle Standard displacement

-60 -0.011605

-50-0.005045

-40-0.001763

-30-0.000440

-20-0.000060

-10 -0.000002

0 0

0.000002

0.000060

0.000440

0.001763

0.005045

60 0.011605

  Data is also represented graphically

  by the REF B curve in FIG. 9.

  The aforementioned patent also showed that the longest non-inverting rest, for N = 2, was obtained with F1 = 1.33 (4/3) and F2 = 0.167 (1X / 6). Using these values in equation (9) gives the normalized shift for various

clock angles.

TABLE III

  Clock angle Standard displacement

-60 -0,005862

-50-0.002452

-40-0.000830

-30-0.000202

-20-0.000027

-10 -0.000001

0 Q

0.000001

0.000027

0.000202

40 0.000830

0.002452

0.005862

  These results are also indicated graphically by the REF C curve in FIG.

  REF A, REF B and REF C curves show two essential points.

  First, when comparing the rest periods given by the dependent mechanisms, the rest of the mechanism 30 are significantly larger than the rest obtained at top dead center or at the bottom dead center of a crank and crank mechanism. The second observation concerns the directional behavior of the movement in the neighborhood of the rest. Compared to the connecting rod and crank mechanism, it is noted that the displacement on either side of the center of repose, at the point where the clock angle is equal to zero, constituting the position of the top dead center or the bottom dead center, is unidirectional as can be expected with a mechanism

  inversion such as a rod and crank mechanism. On au

  on the other hand, it can be noted that, with respect to the mechanism 30, the displacement on either side of the center of rest is

  bidirectional, what can still be expected for a

  such a positioning mechanism, that is, when the input shaft rotates in the same direction, the output member temporarily stops after a

  given positioning, but accelerates again as

  in the sense that it had before the judgment.

  The previous results concerning the characteristics

  Approximate rest rates of each of the independently working mechanisms constitute reference results for the results according to the invention indicated

in the following.

  In the combined mechanism of Figures 7 and 8 according to

  the invention, equation (7) must undergo a new change

  scale representation so that it represents the true exit angle of the shaft 52 of the mechanism 30. If the number of positioning cycles per revolution of the output shaft 52 is called M, the instantaneous position of the shaft 52 as a function of the clock angle can be represented by

  multiplication of equation (9) corresponding to the displacement

  standardized cement, by 360 / M which represents the number of degrees of rotation per positioning cycle of the shaft 52. Consequently, we obtain: y = 360 - 2 sinC + 2 sinNc] (10) The equation is simplified under the form: y C 360E1 360E1 (11) -M TwM sinC + 7-M-sinNc (11)

  In the combined mechanism of Figures 7 and 8, the

  output of the shaft 52 given by y of equation (11)

  is equal to the angle of entry of the connecting rod mechanism and

  Figure 5 as shown in equation (3) of

  approximate number. A new variable C1 representing the phase angle when connecting the two mechanisms, must be introduced. If the shaft 52 is arranged so that it is between the positioning cycles of the mechanism 30, that is to say if the clock angle qC is equal

  at zero, the angle of exceedance of the neutral point

  velle is given by the phase angle C1. As a consequence: = y + C1 (12) The combination of equations (12) and (3) gives: D = R [1 - cos (y + C1)] (13) When the output stroke is equal to 1, R = DU = 2 [1 - cos (y + C1)] (14)

  When the value of equation (11) is

  equation (14), the normal displacement equation

  of the mechanism according to the invention is obtained in the form: 1 - o C 360E1 360E1 Du = 7 [1 cos (2M-sinc + 2MT sinN C + C1)] (15) This equation contains five parameters M, N, C1 , E1

  and E2, each having its own influence on the characteristics

  ticks of the exit movement. The number of combinations

is obviously very important.

  Some -combinations are represented so

  that they illustrate the influence of these various parameters.

  On the illustrations, the various tables and curves were calculated using a computer. For example,

  velocity can be calculated by mathematical techniques

* classic ticks, but it is obviously less loing and tedious to use numerical differentiation

performed by computer.

  One of the important practical applications of the invention is the creation of significant rest at

  two ends of the race. For example, this characteristic

  tick allows the operation of other mechanisms when the mechanism according to the invention is at rest. The combination

  individual mechanisms so that

  cident, that is to say C1 = 0, and the arrangement of the mechanism 30 so that it has a position angle of 180, with M = 2 and with the factors F1 and F2 determined so that they give the rest "the flatter" possible, obtained according to the aforementioned patent of the United States of America,

  allow the calculation of the following cases.

Case 1

C1 = 0 M = 2 N = 3

E1 = 1.125 E2 = 1/24

  The results are given in Table IV.

Clock angle -80 -70 -60 -50 -40

-30 to +30

TABLE IV

Standardized displacement

0.003972

0.001291

0.000332

0.000063

0.000008

less than 0.000001

0.000008

0.000063

0.000332

0.001291

0.003972

  These results are also indicated by curve D in FIG. 9. It should be remembered that. rest curve represents the exit movement of the combined mechanism

  independent mechanisms whose characteristics are

  Resting ticks are presented by the REF A and REF B curves, and it is noted that the resting characteristics of the combined mechanism are much better than the simple addition of the rest of the individual mechanisms. It is furthermore clear that the movement of the mechanism

  combined, in a predictable manner, retains the characteristics

  inversion ticks of the connecting rod and crank mechanism,

  and that the displacement curve D of FIG. 9 is symmetrically

  compared to the O axis, as was the REF A curve. Case 2

  This case is comparable to Case 1, but with

  version of the mechanism 30 corresponding to the second harmonic, instead of the third given by the curve D. Consequently, we obtain:

C1 = 0 M = 2 N = 2

F1 = 1 1/3 F2 = 1/6

  The results are shown in Table V.

TABLE V

  Clock angle -90 -80 -70 -60 -500 -40o

-30 to +30

      9o0 Normalized displacement

0.003520

0.001228

0.000360

0.000085

0.000015

0.000002

less than 0.000001

0.000002

0.000015

0.000085

0.000360

0.001228

0.003520

  These results are also indicated by the curve E of Figure 9, the observations made with reference to the

curve D still applying.

  In the aforementioned United States patent, techniques have been developed for the determination of the values of E1 and E2 for both the second and third harmonic, N = 2 and N = 3, although that the displacement can be zero for four different cancellation angles which are predetermined values of the clock angle for which the output displacement is zero. The generic qualitative characteristics of such a condition are shown in Figure 10. It is noted that the output displacement of the mechanism

  shown in FIG. 10 passes through 0 at a predetermined angle

  minus clock defined as a compensation angle for - 0N2, slightly exceeds the reference curve and then returns to a zero value for a second angle

  predetermined cancellation -eN1. It then exceeds in the

  the direction of the reference line and returns to a zero output displacement for the clock angle 0. The behavior of the mechanism 30 for the positive clock angles is symmetrical, with respect to the center and not with respect to a

  plan, its behavior for the negative angles of hor-

  box. Accordingly, the exit movement of the mechanism 30 may be essentially determined so that it passes five times by 0 during a rest, and it is considered that

  This is a 5-place rest.

  As stated in the aforementioned patent, the amplitude

  movements on either side of the line of reference

  can be adjusted by judicious selection of the cancellation angles. Using a computer, it is possible to manipulate the angles of cancellation empirically, by approximations

  successive steps or by iteration so that the amplitudes pre-

  determined oscillation and associated factors E1 and

  E2 are obtained. In general, the four amplitudes dis-

  oscillation tincts are made equal, without

this is indispensable.

  The output displacement of the mechanism 30 designates the crank angle of the crank and crank mechanism and is thus indicated in FIG. 10. When the phase angle C1 is equal to 0, the resulting output signal of the combined mechanism has the generic form shown in Figure 11 following the oscillation of the crank

  shown in Figure 10. It should be noted that the oscilla-

  output of the combined mechanism is unidirectional given the inherent characteristics of the crank mechanism, the output movement being symmetrical with respect to the neutral point, ie for a given angle the output movement is the same, that the angle

  either in advance or behind the dead point.

  This is confirmed mathematically by equation (3)

that cos (e) = cos (-8).

  When a determined amplitude of rest (normal

  is determined for a particular application, the following technique is useful. Equation (3) is solved

  compared to 0 and R is made equal to 2, so we get

  holds: cos = 1 - 2 DU = arc cos (1 - 2 DU) (16) In the case of the combined mechanism and given the relation indicated in FIGS. 10 and 11, it is noted that equation (16) determines the permissible angle of oscillation of the crank intended to give a predetermined amplitude

  rest. Table VI shows the permitted angles of

  crank release as a function of the resting amplitude, for an output movement of 180 of the mechanism 30 (M = 2) giving a long rest at each end of the stroke.

TABLE VI

  Normalized amplitude Amplitude of oscillation Normalized oscillation qof permitted rest of crank crank predetermined actual degrees position 180

0.00001 + 0.36237 + 0.00201

0.00003 + 0.62765 + 0.00348

0.00010 + 1.14593 + 0.00636

0.00030 + 1.98488 + 0.01103

0.00100 + 3.62431 + 0.02014

0.00300 + 6.27958 + 0.03489

  For the allowable crank oscillation amplitude determined for a defined rest amplitude of the combined mechanism, as shown in equation (16) and as shown by the examples in Table VI, it is possible to use the amplitudes of crank oscillation for the determination of the angles of cancellation and the factors

  E1 and E2 which give them. As mentioned above, the operation

  ration is performed by approximation techniques

  successive using a computer.

  The values of the cancellation angles were determined from this procedure to give the allowable crank oscillation amplitudes that were shown in Table VI. These values are indicated in Table VIIA in the case of N = 3 and in Table VIIB in the case of N = 2 for positioning.

180 of the mechanism 30.

Amplitude of rest

0.00001

0.00003

0.00010

0.00030

0.00100

0.00300

Amplitude of rest

0.00001

0.00003

0.00010

0.00030

0.00100

0.00300

TABLE VIIA N =

  Angle of cancellation 1 degree clock

+ 36,884

+ 40,110

+ 43,661

+ 46,816

+ 50,040

+ 52,642

TABLE VIIB N =

  Angle of cancellation 1 degree clock

+ 44,909

+ 49,262

+ 54.273

+ 58,991

+ 64,206

+ 68,874

  Angle of cancellation 2 degrees clock

+ 62.047

+ 68.095

+ 75.045

+ 81.563

+ 88.710

+ 95.013

  Angle of cancellation 2 degrees clock

+ 74.615

+ 82.361

+ 91.502

100.389

110.624

120.266

-

  For the cancellation angles indicated in Tables VIIA and VIIB, the necessary factors E1 and E2 can be calculated by carrying out the process indicated in the aforementioned patent. When the operation is carried out

  with the particular values of the cancellation angle indi-

  In tables VIIA and VIIB, for the desired amplitudes of rest, the corresponding factors E1 'and E2 are

  listed in Tables VIIIA and VIIIB.

TABLE VIIIA N = 3

  Amplitude of rest Factor E1 Factor E2

0.00001 1.2149 0.0913

0.00003 1.2326 0.1090

0.00010 1.2545 0.1379

0.00030 1.2762 0.182

0.00100 1,3008 0.2483

0.00300 1.3227 0.3528

TABLE VIIIB N = 2

  Aplitude rest E1 factor E2 factor

0.00001 1.4947 0.2714

0.00003 1-, 5311 0.3037

0.00010 1.5791 0.3530

0.00030 1.6309 0.4170

0.00100 1.6969 0.5197

0.00300 1.7647 0.6603

  The aforementioned factors E1 and E2 can then be used in equation (15) for calculating the normalized output displacement of the combined mechanism. It will be remembered that the procedure for determining E1 and E2, in this case, was predicted from the mechanism 30 having an exit angle of 180, M = 2, and that

  the phase angle C1 was equal to 0, so that

  meters of two illustrative cases can be established.

Case 3

C1 = 0 M = 2 N = 3

E1 = 1,3008 E2 = 0.2483

  Factors E1 and E2 were chosen arbitrarily

  in Table VIIIA to illustrate a rest condition, at the ends of the stroke, having an amplitude of 0.001 of the total stroke using the third harmonic N = 3. The factors indicated previously have been reported in FIG. equation (15) and the displacement was calculated at suitably spaced clock angles. The results of these calculations are indicated by the curve F of FIG. 12 in which only the positive clock characteristics are shown. It should be noted that the behavior, at negative clock angles, is symmetrical with respect to the clock angle axis 0-as shown in the fundamental curve of FIG. 11. Curve F in FIG. the displacement oscillates in the predetermined amplitude, rest of 0.001 on

  a total angle of + 90 is a total rest of 190,

  190/360 or 52.7% of the total cycle time. It should also be noted that the displacement curve F is tangent to the displacement axis 0 for the clock angles

    and 80, in a manner that corresponds to the angles of annula-

  lation for rest amplitude 0.001 represented on the

table VIIA.

  The same objective of a very long rest at each end of the curve is now illustrated in the case where N = 2, as represented generically on the

Figures 1 and 2.

Case 4

C1 = 0 M = 2 N = 2

E1 = 1.6969 E2 = 0.5197

  E1 and E2 were derived from Table VIIIB for a rest range of 0.001 so that the

  behavior of rest for N = 2 can be compared direc-

  to the curve F. for which N = 3. Using these values given in equation (15), the results of the curve G of FIG. 12 were obtained. There is a significant increase in rest length of + 118, which is a total rest length of 236 per

  ratio to the clock angle of a total cycle of 360. The or-

  The output channel is therefore fixed, with an amplitude of rest

  0.001, during 236/360 or 65.5% of the total cycle.

  Although obtaining long rest periods is important in practice, the kinematic behavior of the system must

  also be examined while moving between these rest periods.

  As previously stated, speed calculations are done using a computer and by numerical differentiation rather than conventional differentiation and later calculation with much more elaborate equations

  than equation (15). The use of these techniques has

  put the calculation of speeds during the race for the four cases described previously as shown in Figure 13. The curve D 'represents the speed characteristics of the case 1 whose rest characteristics are

  indicated by curve D in Figure 9. These characteristics

  speed ticks are symmetrical with respect to the angle

  180 and the speeds at the lower clock angles

  60 are too weak to be of interest.

  the speeds are carried as the relative speed which is determined to be the ratio of the instantaneous speed for a given clock angle, divided by the average speed which is equal to the total stroke divided by the time required for the travel of a clock angle

from 360.

  Similarly, the speed curve E 'represents the conditions of case 2 and is the counterpart of the rest curve E of FIG. 9. The speed curve F' corresponds to case 3 and is the counterpart of the rest curve F of FIG. 12, and the speed curve G 'represents case 4 and is the counterpart of the rest curve G of FIG. 12. The maximum speeds, in a very general manner, in the cases where N = 2, as the curves E 'and G', are greater than those of the case in which N = 3 as indicated by the curves D 'and F' and as can be expected since the rest, in cases N = 2, are longer than those of cases in which N = 3. It is interesting to note that the curve F ', which represents a configuration which has a longer rest than the other curve D' of the third harmonic, has a reversal of speed near mid-race, which is a clean feature of using a component

  important of the third harmonic.

  In the previous four cases, it has been shown how the rest, at each end of the race, could be made very important, when expressed as a fraction of the total cycle time per stroke, and the speed characteristics. have been indicated between the ends of the race according to the chosen conditions. There are other applications in which it is desirable for rest to be obtained during the races, in addition to the reversal rest at the ends of the race. Three additional cases are used so that they indicate how this characteristic can be obtained. The first case uses a phase angle C1 intended to remove the rest of the mechanism 30 of the inversion rest of the connecting rod and crank mechanism. A value C1 = 90 is obtained by positioning the crank on the output shaft of the mechanism 30 in such a way that it is at 90 of its neutral position when the mechanism is at the center of its rest position. When the value N = 2 is further affected, so that the output positioning angle of the mechanism 30 is equal to 180, a rest is created in the middle of the race in one direction.

  and in the other. The angular oscillation rest amplitude

  crank arm during rest is arbitrarily adjusted

  at + 0.18 and the values of E1 and E2 are obtained by iteration using a computer. N has been set to 3 although, as previously indicated, N2 gives a slightly longer rest at the expense of higher speeds. As a result, the conditions of Case 5 have

  been established in the following manner.

Case 5

C1 = 90 M = 2 N = 2

E1 = 1.196 E2 = 0.0761

  The results obtained with these conditions then

  calculated at appropriate intervals of hori-

  and have been plotted on the curve H of FIG. 14. The normalized displacement is represented on an interval

  clock angle of 720 which represents two positions

  180 operations of the mechanism 30, necessary for the movement of the crank 360 total, so that the advance stroke and the return stroke are represented. It can be noted in Figure H that an important rest was created halfway to a normalized displacement equal to 0.5, while

  the rest of the ends of the race are very weak.

  In other applications, a long rest during the race is desirable, at a certain location during a race in advance and at another location during the return run. This is allowed, between certain limits, by modifying the phase angle C1 so that it takes a suitable value differing from 90 and used for the creation of the conditions of the curve H, the other parameters not being modified, arbitrarily . Case 6

C1 = 60 M = 2 N = 3

E1 = 1.196 E2 = 0.0761

  The results are indicated by the curve J of the

  Figure 14 in which the phase angle C1 is equal to 60.

  The long intermediate rest corresponds to a standard output displacement of 0.25 in the advance stroke and 0.75 in the return stroke, as can be expected by considering equation (14) and using y = 0 for the first rest position and y = 180 for the second rest position. Obviously, when M = 2, the two rest positions are always separated by the same distance from the previous inversion rest; in other words, the sum of the normalized displacements of the two intermediate rest positions is always equal

  This feature can be changed by

  intermediate linkage, before the location

final training.

  When using the parameters shown for cases 5 and 6, the rest of the ends of the strokes can be very short, as shown for

  a crank turning at a determined angular speed.

  However, there are applications in which it takes a long rest at the ends of the race as well as at the midpoints of the race. This feature can be achieved by selecting an output position angle of 90 for the mechanism 30, this characteristic

  being obtained by adjusting M to 4. A rest at five

  as shown in Figure 10 has been selected.

  tion, with a rest amplitude of +0.09 (normal value

  0.001) for the oscillation of the crank, and the final parameters, calculated as previously described, are

The following.

Case 7

C1 = 0 M = 4 N = 3

E1 = 1.196 E2 = 0.0761

  The results of the calculations are indicated by the curve K in FIG.

  total clock angle of 1440 C, which is necessary to

  that four cycles of the mechanism are needed per turn

  crank, each cycle requiring 3600 hori-

  box. It should be noted from curve K that, in addition to long rest at mid-stroke, the rest of the ends of the race are notably longer than those of

  cases 5 and 6 represented by the curves H and J of the

gure 14.

  There are certain applications in which it is desirable for a reversing mechanism to have a very long rest at one end of the stroke and a relatively short rest at the other end of the stroke. This characteristic can be obtained according to the invention by using an output positioning angle or

* cycle 360 for mechanism 30, with M = 1, and by position

  the crank angle so that the phase angle is 0, ie C1 = 0. Obviously, the crank is then at a dead point when the mechanism is at rest; at the opposite dead point of the crank, the mechanism 30 is in the middle position of its cycle and rotates at a relatively high angular velocity. This situation creates the system rest difference at the opposite ends of the race. Two particular examples are indicated, one with N = 2 and the other with N = 3. In each example, a five-slot rest with

  amplitude of 0.001 was chosen arbitrarily. These characteristics

  The tables give the following combinations of parameters.

Case 8

C1 = 0 M = 1 N = 3

E1 = 1,273 E2 = 0.1703

  The results of the calculations carried out with these parameters, carried in equation (15), are represented

by the curve L of FIG.

Case 9

C1 = 0 M = 1 N = 2

E1 = 1.622 E2 = 0.4048

  The results of the calculations made with these

  The parameters are represented by the curve M of FIG.

  The curve L was drawn using N = 2 and the curve M with the use of N = 3. In all cases, the parameters E1 and E2 were determined by successive approximation with the aid of the computer. so that the amplitude of rest of the whole system is 0.001 as indicated previously. The curves are only worn for 180 clock angle because they are symmetrical both around clock angles 0 and 180. As can be expected from FIGS. 9 and 12, rest at a first end of the stroke is more important for N = 2 than for N = 3. As a result, given the speed compensation angular

  halfway up the case N = 2, the rest at the other extreme

  the race is shorter for N = 2 than for N = 3 or, in other words, the inversion is faster in

the case N = 2 only in the case N = 3.

  In cases 3 to 9 above, the parameters E1 and E2 were determined by considering a rest at five locations as described with reference to Figures and 11. This feature has been described in more detail in the aforementioned patent. As also described in this patent, it is possible to realize the mechanism 30 so that its displacement characteristic, in the rest zone, goes to zero only three times and not five,

  the rest being then called "rest at three locations".

  The main purpose of reducing the number of resting points from 5 to 3 is that this operation makes it possible to determine combiners of E1 and E2 which allow a better adjustment of the kinematics characteristics of the

  movement between rest. In the case of the independent mechanism

  In numeral 30, numerous examples are presented in the aforementioned patent, in particular the kinematic curves of FIGS. 12, 13, 30 and 31 of this patent. The generic characteristics of displacement

  the output of the mechanism 30 in the three-position rest mode.

  ments, are shown in Figure 17.

  placement becomes the crank angle of the mechanism to

  crank and crank, we give it this name. Enjoyed-

  any of these methods may be used for creating a three-slot rest, as indicated hereinafter. It is assumed that the parameters E1 and E2 have been set to give a three-slot rest condition for the mechanism 30, and the output angular displacement of the mechanism or crank angle is generically represented by

  the curve in Figure 17. It can be noted that the "over-

  crankshaft position relative to its position 0 after cross-referencing: of the reference axis, are at a negative clock angle called the angle of cancellation - 1 The displacement of the crank angle then changes direction and goes through the position of 0 again for a clock angle equal to 0 and then passes the other side before changing direction and intersecting the zero displacement position for a positive clock angle determined as the angle 8N1 When the parameters E1 and E2

  are determined so that they create a rest at three locations.

  cements, the angular displacement output of the mechanism 30 undergoes a triple pass on the reference axis with two changes of direction whereas, when the parameters E1 and E are determined so that they give a rest at five locations as described above, the angular displacement output which is the crank angle, undergoes

  four inversion and cuts five times the reference axis.

  When the crank is placed on the output shaft of the mechanism 30 so that it is in neutral when the mechanism is in the center of its

  rest, the normalized output displacement according to the invention.

  can be as represented by the generic curve of Figure 18 which is drawn from Figure 17 by the

  same technique that has already been used for description

  of the curve of Figure 1 1 compared to that of the

  Figure 10. The normalized output displacement of the

  This is essentially equal to 0 for the angles -0N1 '0 and 0N1' the crank angle being equal to 0 or being very slightly positive while the crank angle is slightly positive or negative as described with reference

in Figure 11.

  The method of determining factors E1 and E2 in the case of a three-slot rest is comparable to that used for determining rest at five locations. The use of the techniques already used for the determination of the groups of solutions in the case of rest at three locations, in the aforementioned patent, makes it possible to calculate the total amplitude of the rest then the adjustment of E1 or E2 so that the desired amplitude of rest is obtained. The unused factor E1 or E2 (used for amplitude determination

  of rest) is then modified so that the objective

  The desired kinematic value is reached, but for each variation of the parameter (E1 or E2) used to search for the kinematic objective, the parameter (E1 or E2) which created the rest amplitude must be re-evaluated. It is still a successive approximation technique for

  which a computer is virtually indispensable.

  The values E1 and E2 can be found to the extent that they can be obtained mathematically,

  even without taking into account the teachings of the aforementioned patent.

  A value is arbitrarily assigned to E1 or E2 and the unassigned variable E2 or E1 is modified to give the desired amplitude of rest, using equation (15) as a fundamental basis for the calculations of the standardized displacement. The affected parameter E1 or E2 can then be modified by successive approximation so that it gives the desired kinematic characteristics to the movement during the race, two examples being now considered. Two cases are studied, in the context of the preceding conditions, one in which N is arbitrarily chosen as being equal to 2 and the second in which N is arbitrarily chosen at a value equal to 3. The use

  information obtained in the description of the cases

  cents allows the selection of the value 2 for M so that a long rest is created at both ends of the

  race. The amplitude of rest was again chosen arbitrarily

  at a value of 0.001, expressed in coordinates of

standardized displacement.

  With these conditions and parameters and when N was made equal to 2, E2 was set between -0.1 and -0.3, in steps of 0.01, using curve B in FIG. aforementioned patent. For each chosen value of E2, a

  corresponding value of E1 was determined by approxima-

  successive motion so that the displacement at rest equals 0.001. For the thus fixed values of and E2, the 1 E 2, speed characteristics during the stroke were calculated at suitable clock angles with equation (15) and by numerical differentiation. One result was selected from the many combinations of E1 and E2 as best meeting the above criteria, and these

The results are as follows.

Case 10

C1 0 M = 2 N = 2

E1 = 0.9190 E2 = 0.22

  The rest characteristics corresponding to this combination of parameters are indicated by the

  curve N of FIG. 19, these characteristics being symmetrically

  in relation to the clock angle 0 as indicated

  the generic rest curve of Figure 18.

  The speed characteristics of this combination are indicated by the curve N 'of FIG. 20 in which the speeds, below a clock angle of 50, are too small to be interesting and the speeds are symmetrical with respect to clock angle of 180. It should be noted that the rest and velocities for the "neighbor" solutions determined for E2 = -0.21 and -0.23 differ almost imperceptibly. These combinations are as follows:

E2 = - 0.21 E1 = 0.9361

E2 = - 0.23 E1 = 0.9018

  The following values of E1 and E2 were chosen according to the highest satisfaction of the criteria, by the same operations but with N = 3 instead

N = 2 in case 10.

Case 11

C1 = 0 M = 2 N = 3

E1 = 1.355 E2 = 0.11

  The quiescent characteristics of this combination of parameters are indicated by the curve P in FIG. 19 and the velocity characteristics are indicated by the curve P 'of FIG. 20, with the same symmetries as before, as described with reference to the curves N

and N'.

  Obviously, the number of character variants

  Kinematic data which can be obtained according to the invention is extremely large. The cases indicated are purely illustrative. Each of the cases implements a rest of one type or another, but the invention is not limited to cases where rest is necessary. In general, it can be implemented to obtain any desired kinematic characteristic which can be represented approximately by equation (15), this characteristic being itself determined to a large extent by knowledge, experience and the abilities of a designer implementing this

  equation and the mechanism it represents.

  All previous curves were obtained from Equation (15) which was drawn with some simplifications. However, when rigorously calculating the characteristics of these systems without approximation, during a computation performed on a computer (the mathematical calculations without approximation are much too complex), we see that we can determine a very high degree of correlation between the features described herein and the exact characteristics calculated numerically. These operations include the adjustment, by successive approximations, of the distances between the axes Ao and A4 and between the axes A1 and A2, as well as the distances mentioned above between the

  axes A2 and A3 (E1) and between axes Ao and A1 (E2).

Claims (15)

  1. Alternative drive mechanism, intended to give extremely varied kinematic characteristics, including very long rest at the ends of the race, unequal rest at the opposite ends of the race, intermediate rest between the ends of a race and an asymmetrical displacement during a displacement in a first direction relative to the displacement in the other direction, characterized in that it comprises:   at. a unidirectional rotary drive mechanism   device (30) having a cyclically variable output member, comprising: 1. a frame, 2. an output shaft (52) mounted to rotate in the frame, 3. an output member (50) mounted on the tree   output and intended to be trained   4. a first rotational pair supported by the frame and comprising: (i) a first rotatable member (32) mounted for rotation in the frame, and (ii) a first eccentric member (34) eccentrically mounted on the frame; first   rotating body but without the power to to him,   5. a second rotating pair mounted in position   fixed in space relative to the first rotary pair and comprising: (i) a second rotatable member (40), and (ii) a second eccentric member (48) eccentrically mounted on the second rotatable member to can not turn in relation to him,   6. a device (36, 38, 40) ensuring the connection   rotation of the first and second   second rotating pair so that they pre-   have a substantially integral ratio of angular velocities, 7. a device (54) connecting the output member to the second eccentric member (48) to drive each other, and 8. a motor device (92) connected to the one of the rotating pairs and intended to drive this pair in rotation,   b. an alternative drive mechanism for   tie, comprising: 1. a crank (66) mounted at its first end. on the output shaft (52), 2. a rod (70) journalling, at the first   end, on the other end of the   level, and 3. an alternative output device (72) mounted so that it moves in translation in the chassis and hinged to the other end of the connecting rod.   2. Mechanism according to claim 1, characterized   in that the driving device is connected to the first gear rotary shaft (32).   3. Mechanism according to claim 1, characterized in that the output member (50) has a pitch diameter which is twice that of the second eccentric member (48). 4. Mechanism according to claim 1, characterized in that the crank (66) is mounted on the shaft of   output (52) so that when the input mechanism -   rotation is also arranged between the two adjacent positioning cycles, the crank (66) and the   connecting rod (70) are substantially collinear.   5. Mechanism according to claim 1, characterized in that the pitch diameters of the output member (50)   and the second eccentric member (48) are equal.   6. Mechanism according to claim 1, characterized in that the output member (50) has a pitch diameter   which is four times that of the second tramp (48).   7. Mechanism according to claim 1, characterized in that the crank (66) is mounted on the output shaft (52) so that when the rotational drive mechanism is equidistantly spaced between two cycles adjacent positioning, the crank makes a predetermined phase angle with a reference position in which the crank (66) and the connecting rod (70) are substantially collinear.   8. Alternative drive mechanism, intended for   give extremely dynamic cinematic characteristics   verses, comprising very long rest at the ends of the race, unequal rest at the opposite ends of the race, intermediate rest between the ends   of a race, and an asymmetrical displacement during the   cement in a first direction relative to the displacement in the other direction, characterized in that it comprises:   at. a unidirectional rotary drive mechanism   having an output varying cyclically, comprising: 1. a frame, 2. an output shaft (52) mounted in the frame for rotation, 3. an output gear (50) mounted on the output shaft and 4. A first rotational pair supported by the frame and comprising: (i) a first rotatable member (32) mounted in the frame for rotation, and (ii) a first eccentric pinion (34). ) mounted eccentrically on the first rotatable member so that it does not rotate relative thereto,   5. a second rotating pair mounted in the   pace in a fixed position in relation to the first   a first rotary pair and comprising: (i) a second rotatable member (40), and (ii) a second eccentric pinion (48) eccentrically mounted on the second rotatable member and not rotatable relative thereto, 6. a device (36, 38, 40) connecting the first and second rotational pairs to rotate with a substantially integral ratio of angular velocities,   7. a device (54) for connecting the   output and the second outer gear   to engage, and 8. a motor device (92) connected to one of the rotating pairs and for rotating the pair, and   b. an alternative drive mechanism for   comprising: 1. a crank (66) mounted at its first end on the output shaft (52), 2. a crank (70) journalled at its one end on the other end of the crank, and 3. a reciprocating output device (72) mounted so that it moves in translation in the chassis and articulated on the other end of the connecting rod.   9. Mechanism according to claim 8, characterized in that the motor device is connected to the first rotary member (32).   10. Mechanism according to claim 8, characterized in that the output gear (50) has a pitch diameter which is equal to twice that of the second eccentric gear (48). 11. Mechanism according to claim 8, characterized in that the crank (66) is arranged on the shaft   the output device (52) so that when the   rotary drag is equidistant between two adjacent positioning cycles, the maniyelle (66) and the   connecting rod (70) are substantially collinear.   12. Mechanism according to claim 8, characterized   in that the pitch diameters of the output gear (50) and the second eccentric gear (48) are equal. Mechanism according to claim 8, characterized in that the output gear (50) has a pitch diameter   which is four times that of the second upper gear tramp (48).   14. Mechanism according to claim 8, characterized in that the crank (66) is mounted on the shaft of   output (52) so that when the training mechanism   The crank is at an equal distance between two adjacent positioning cycles, the crank has a predetermined phase angle with respect to a reference position in which the crank (66) and the connecting rod   (70) are substantially collinear.