FR2639704A1 - Mechanism with crossed movements - Google Patents

Abstract

The present invention relates to a mechanism with crossed movements, including a bed 1, a first moving member 2 capable of sliding parallel to a plane with respect to the said bed, a second moving member 3 capable of sliding parallel to the said plane, and first 12 and second 13 motor means for driving the said first and second moving members, respectively, the said first and second motor means being mounted at a fixed station on the said bed and being connected to the said first and second moving members by means of first 14 and second 15 transmission means. According to the invention, the said second transmission means consist of a bar 15 slidingly guided along its longitudinal axis YY' with respect to the said bed 1, and the said bar 15 is connected slidingly to one of the said moving members 3. The invention applies to the observation of objects, using a diascope (still projector), for example, as well as to precision machining.

Description

The present invention relates to a crossed movement mechanism. Although not exclusively, the mechanism of the invention is more particularly intended for use with a device for observing an object, for example by transmitted-light vision.

By documents US-A-2 792 953 and EP-O 076 268, mechanisms with crossed movements are already known, comprising a frame, a first movable member which can slide parallel to a plane relative to said frame, a second movable member which can slide parallel to said plane, and first and second motor means for driving said first and second movable members, respectively. These can be in the form of trolleys shaped into frames. In order to reduce the inertia of the movable members, the drive means are mounted on a fixed station on the frame, and are connected to the first and second movable members via first and second transmission means. More precisely, in these known mechanisms , said first movable member is guided in sliding, relative to the frame, along a first rectilinear direction, while said second movable member is guided in sliding, relative to said first movable member, along a second straight direction different from the first.

The object of the present invention is to improve such a known mechanism, in order to free as much as possible the overlap area of said movable members, occupied by said transmission means, and thus to obtain as wide a field of observation as possible, for an object moved by said mechanism in front of an observation device.

To this end, according to the invention, the mechanism with crossed movements, of the type comprising a frame, a first movable member that can slide parallel to a plane relative to said frame, a second movable member that can slide parallel to said plane, and first and second drive means for driving said first and second movable members, respectively, said first and second drive means being mounted on a fixed station on said frame and being connected to said first and second movable members via first and second transmission means, is remarkable in that said second transmission means consist of a bar guided in sliding along its longitudinal axis, relative to said frame, and in that said bar is slidably connected to one of said movable members.

Preferably, said first transmission means consist of a bar guided in sliding along its longitudinal axis relative to said frame and connected to said first movable member.

Thus, said transmission means consist only of two bars which intersect, so that maximum space is left free by said transmission means, in plan. In addition, these two bars can be arranged to be outside the field of observation.

According to a first embodiment in which, in known manner, said first movable member is guided in sliding, with respect to said frame, along a first rectilinear direction, while said second movable member is guided in sliding, with respect to said frame first movable member, along a second rectilinear direction different from the first, then said sliding bar of said second transmission means is slidably connected to said second movable member.

Advantageously, said first and second movable members each consist of a carriage in the form of a frame having four parallel crosspieces two by two.

On the other hand, in a second embodiment of the invention, said sliding bar of said second transmission means is intended to form said second movable member, said first movable member can move freely in sliding in all directions of its sliding plane , and the sliding bar of said second transmission means is slidably connected to said first movable member.

In this second embodiment, it is also advantageous, when said first transmission means are constituted by a bar guided in sliding along its longitudinal axis, that said bar is slidably connected to said first movable member.

Preferably, in this same embodiment, the bar of the second transmission means is rigid, and / or has a cross section of substantially rectangular shape.

Advantageously, said first movable member consists of a frame-shaped carriage having four cross members in pairs.

Preferably, said motor means intended for driving the sliding bar of the first and / or second transmission means comprise a rotary drive member, such as a roller or a pinion, pressed against said bar and associated with opposite sliding or rolling back pressure means.

It will be noted that, in the first embodiment described above, the bar of said first transmission means could theoretically be rigidly connected to said first movable member. However, in the case where said bar has a certain flexibility, especially if it is driven by the motor means with rotary drive member and back pressure means, as just mentioned, it is advantageous that the connection between the bar of said first transmission means and said first movable member is sliding, so as to avoid jamming.

Furthermore, conveniently, aerostatic pads allow the sliding of the first and second movable members and of the said bar or bars.

In addition, in the second embodiment, the four corners of the frame formed by said first movable member are each provided with an aerostatic pad, also suitable for playing the role of a suction cup.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 is a top view of a first embodiment of the cross-movement mechanism of the invention.

Figure 2 is a sectional view along the line II-II in Figure 1.

Figure 3 is a sectional view along line III-III of Figure 1.

Figure 4 is a top view of a second embodiment of the cross-movement mechanism of the invention.

Figure 5 shows an enlarged detail of the mechanism of Figure 4.

Figure 6 is a sectional view along line VI-VI of Figure 4.

Figure 7 is a sectional view along line Vil-Vil of Figure 4.

FIG. 8 is a sectional view along the line Vili-Vili of FIG. 4.

Figures 9a and 9b are sectional and bottom views, respectively, of an aerostatic pad.

Figures 10a and 10b are sectional and bottom views, respectively, of an aerostatic pad which can also act as a suction cup.

 Reference will firstly be made to FIGS. 1 to 3 illustrating a first embodiment of the invention.

The cross-movement mechanism comprises, in this case, a frame 1, a first carriage 2 shaped as a frame having four parallel crosspieces two by two 2a, 2b, 2c, 2d, which can slide parallel to a plane P relative to the frame 1, in a first rectilinear direction Ox, a second carriage 3 shaped as a frame having four parallel crosspieces two by two 3a, 3b, 3c, 3d, which can slide parallel to the plane P, relative to the first carriage 2, in a second rectilinear direction Oy perpendicular , in this example, to the first direction
Ox. The first carriage 2 is guided in sliding, relative to the frame 1, on aerostatic pads 4, provided at the four corners of the frame forming the carriage 2, and described in more detail below with reference to Figures 9a and 9b.

The pads LI are arranged in pairs and can slide on corresponding guide surfaces 1a and 1b of the frame 1, inclined relative to each other in the manner of a dovetail, as can best be seen. in FIG. 2. In addition, the second carriage 3 is also guided in sliding, relative to the first carriage 2, on aerostatic pads 5, of the same type as the pads 4. We can better see the arrangement of these pads 5 in FIG. 3. On the one hand, two series 6 spaced apart by four pads 5, each of which is applied to a corresponding face of the crosspiece 2b, parallel to the direction Oy, of the carriage 2, are arranged on the underside of the corresponding cross-member 3b of the carriage 3, a shoe 5, in each series 6, being directly mounted on the underside of the cross-member 3b, while the other three shoes 5 are mounted, each on a wing of a U-shaped section section 7 , secured at 8 to cross member 3b. On the other hand, two series 9 spaced two pads 5, each of which applies to the top face and the bottom face, respectively, of the cross member 2d, parallel to the direction Oy, of the carriage 2, are arranged on the underside of the corresponding 3d cross member of the carriage 3, a pad 5, in each series 9, being directly mounted on the underside of the 3d cross member, while the other pad is mounted on the wing, parallel to the underside of the 3d cross member, with an L-shaped section of section 10 , secured at 11 to the 3d crossbar.

Furthermore, first 12 and second 13 motor means are provided for driving the first 2 and second 3 carriages, respectively. The first 12 and second 13 motor means are mounted on a fixed station on the frame 1 and are connected to the first 2 and second 3 carriages via a first bar 14 and a second transmission bar 15, respectively.

The first bar 14 is guided in sliding along its longitudinal axis X, X ', relative to the frame 1, and is connected, in a sliding manner, to the first carriage 2. To do this, on the one hand, at one end of the bar 14, the motor means 12 comprise a rotary drive member 16, such as a roller or a pinion, actuated by a motor (not shown), and pressed against the bar 14 while being associated with counter means - opposite rolling pressure 17, such as rollers, and, on the other hand, at the other end of the bar 14, are mounted, on a U-shaped section 18, two aerostatic pads 19, of the same type as the pads 4 and 5, between which is taken the central branch 20a, parallel to the direction Oy, of a stirrup 20, as can best be seen in FIG. 3.

Similarly, the second bar 15 is guided in sliding along its longitudinal axis Y, Y ′, relative to the frame 1, and is connected, in a sliding manner, to the second carriage 3. To do this, on the one hand, at one end of the bar 15, the motor means 13 comprise, as for the motor means 12, a rotary drive member 16, such as a roller or a pinion, actuated by a motor (not shown), and pressed against the bar 15 by being associated with opposing rolling back-pressure means 17, such as rollers, and, on the other hand, at the other end of the bar 15, are mounted, on a U-shaped section section 21, two aerostatic pads 22, of the same type as the pads 4 and 5, arranged on either side of a slide 23 respectively, arranged on the underside of the cross member 3a of the carriage 3 and parallel to the direction Ox. (Of course, the management
X, X 'is parallel to the direction Ox, and the direction Y, Y' is parallel to the direction Oy).

We will now refer to Figures LI to 8 illustrating a second embodiment of the invention.

The mechanism with crossed movements comprises, in this case, a frame 101 constituting a sliding plane, in which can slide, in all directions, a first carriage 102 in the form of a frame consisting of four transverse beams 102a, 102b, 102c, 102d two by two. For this, the carriage 102 is mounted on four aerostatic pads 103, respectively, provided at the four corners of the frame formed by the carriage 102, and also suitable for playing the role of suction cups. These pads 103 will be described in more detail below with reference to Figures îOa and lOb. In addition, first motor means 104 are provided for entrain # ner the first carriage 102. The motor means 104 are mounted on a fixed post on the frame 101 and are connected to the first carriage 102 by means of a first bar 105 of transmission.

The bar 105 is guided in sliding along its longitudinal axis X, X ', relative to the frame 101, and is connected, in a sliding manner, to the first carriage 102. To do this, on the one hand, at one end of the bar 105, the motor means 104 comprise a rotary drive member 106, such as a roller or a pinion, actuated by a motor (not shown), and pressed against the bar 105 while being associated with means of opposite counterpressures 107, such as rollers, and, on the other hand, at the other end of the bar 105, are mounted two aerostatic pads 108, arranged, respectively, on the wings facing one of the 'another of a U-shaped section 109, so that the two pads 108 are arranged on either side of a slide 110, respectively, coming from the material below the cross member 102b of the carriage 102 (see more particularly Figure 7), and in contact with this slide.

Furthermore, in this exemplary embodiment, the second carriage 111 which can slide, relative to the frame 101, parallel to a direction Oy perpendicular to the longitudinal axis X, X 'of the bar 105, forms the second transmission bar (111 ) slidably connected to the first carriage 102, said bar 111 being rigid and of substantially rectangular cross section.

The sliding of the bar (or of the carriage) 111 along its longitudinal axis Y, Y ′ is obtained by means of the motor means 112 mounted on a fixed station on the frame 101. These motor means 112 comprise a rotary drive member 113, actuated by a motor (not shown), and pressed against the bar 111 while being associated with sliding counter-pressure means 114 opposite. The back pressure means 114 comprise two aerostatic pads 115 mounted on the frame 101, and two aerostatic pads 116, bearing against the face of the bar 111 opposite to that against which the rotary member 113 is pressed, mounted on a sole L-shaped cross section 117 fixed to the frame 101.

 In addition, the sliding of the bar 111 on the first carriage 102 parallel to the direction X, X 'is obtained by means similar to those used to slide the bar 105, parallel to the direction Y, Y', on the carriage 102. Thus, two first aerostatic pads 118 are directly mounted at the end of the bar 111 to bear against a first face 119a of a slide 119 made of material from below the cross member 102a of the carriage 102, and a third pad 118 is in abutment against the face 119b of the slide 119, opposite to said face 119a, while being mounted on a section of profile 120 connected to the bar 111 (see FIGS. 5 and 8).

The structure of the aerostatic sliding pads is illustrated in FIGS. 9a and 9b. In this embodiment, the shoe has a body 200 of substantially conical shape with a circular base 201. The body 200 is pierced through and through by a passage 202 for air (symbolized by the arrow 203), provided by an air supply, not shown, which creates a thin air cushion under the base 201 of the pad, thereby allowing the pad to slide on its support 204.

 The pad 103 shown in FIGS. 10a and 70b can play the role of a sliding pad as in the previous case, but also of a suction cup. For this, the pad 103 has not only an air duct 300 opening at its base 103a to form a thin air cushion there, but also an air duct 301 for creating a vacuum in the annular zone 302. The pad 103 can thus slide on its support 303 and remain attached to it by a suction cup effect.

As already indicated, thanks to the present invention, in particular the use of two crossing transmission bars, a maximum space is left free for the observation of an object, for example by transmitted-light, the two bars being able to elsewhere be arranged to be outside the field of observation.

Claims (11)

1 - Cross-movement mechanism, of the type comprising a frame, a first movable member that can slide parallel to a plane relative to said frame, a second movable member that can slide parallel to said plane, and first and second motor means for driving said first and second movable members, respectively, said first and second drive means being fixedly mounted on said frame and being connected to said first and second movable members by means of first and second transmission means, characterized in that said second transmission means consist of a bar (15,1 il) guided in sliding along its longitudinal axis (Y, Y '), relative to said frame (1,101), and in that said bar (15,111) is slidably connected to one of said movable members (3,102). 2 - Mechanism according to claim 1, characterized in that said first transmission means consist of a bar (14,105) slidingly guided along its longitudinal axis (X, X ') relative to said frame (1,101) and connected to said first movable member (2.102). 3 - Mechanism according to claim 1 or claim 2, wherein said first movable member is guided in sliding, relative to said frame, along a first straight direction, while said second movable member is guided in sliding, relative to said first movable member, along a second rectilinear direction different from the first, characterized in that said sliding bar (15) of said second transmission means is slidably connected to said second movable member (3). 4 - Mechanism according to any one of claims 1 to 3, characterized in that said first and second movable members each consist of a carriage (2,3) in the form of a frame having four parallel crosspieces two by two ( 2a-2d, 3a-3d). 5 - Mechanism according to claim 1 or claim 2, characterized in that said sliding bar (111) of said second transmission means is intended to form said second movable member, in that said first movable member (102) can move freely sliding in all directions of its sliding plane, and in that the sliding bar (111) of said second transmission means is slidably connected to said first movable member (102). 6 - Mechanism according to claim 5, characterized in that, when said first transmission means consist of a bar (105) guided in sliding along its longitudinal axis, said bar is slidably connected to said first movable member (102 ). 7 - Mechanism according to claim 5 or claim 6, characterized in that the bar (111) of the second transmission means is rigid. 8 - Mechanism according to any one of claims 5 to 7, characterized in that the bar (111) of the second transmission means has a cross section of substantially rectangular shape. 9 - Mechanism according to any one of claims 5 to B, characterized in that said first movable member consists of a carriage (102) in the form of a frame having four cross members in pairs (102a-102d). 10 - Mechanism according to any one of the preceding claims, characterized in that said motor means (72,13; 104, 112) intended for driving the sliding bar of the first and / or second transmission means comprise a rotary member entrainment, such as a roller or a pinion, pressed against said bar and associated with sliding or opposing counter pressure means.  it - Mechanism according to any one of the preceding claims, characterized in that aerostatic pads allow the sliding of the first and second movable members and of the said bar or bars. 12 - Mechanism according to claim 9, characterized in that the four corners of the frame (102) formed by said first movable member are each provided with an aerostatic pad (i03), also suitable for playing the role of a suction cup .