EP0191702B1 - Rotatable drawing table with automatic positioning - Google Patents

Description

The present invention relates generally to drawing boards, and more particularly to a drawing board of the type comprising a first fixed part and a second part rotating relative to the first and intended to receive a document to be processed, for example sheet of drawing, this set of fixed part and rotating part taking the place of a drawing device in association for example with a so-called "parallel" displacement ruler or of a drawing device.

Already known from French patent n ° 1 442 551 a drawing board whose part on which the drawing sheet is fixed is rotatably mounted around its center on a support and has a graduation on its external peripheral edge associated with a reference on the support, or vice versa. In this patent, the rotating part of the board is turned by hand and oriented at any angle, then possibly locked in place by means not otherwise described in this patent. These operations, especially if they have to be carried out repeatedly, are long and tedious. In addition, the location of the chosen angle being done visually with respect to the reference line, the precision remains very relative, which is a major drawback for this type of device.

Also known from French Patent No. 2 155 092 is a drawing board which also includes a first fixed part and a second rotating part receiving the drawing sheet. This patent mainly characterizes the automatic positioning of the turntable precisely at predetermined angles, for example using a roller biased by a spring and associated notches provided at the periphery of the rotating part.

However, again in this patent, the operations of rotating the rotating part at any angles are tedious when they have to be repeated often and when these any angles are different from said predetermined angles defined by the notches. Furthermore, no means for blocking the movable part is provided for the angular positions other than those which are predetermined.

We also know tables to draw fixed part and rotating part whose rotating part is rotated by a motor. These tables are equipped with a mechanized tracing device, One and / or the other are controlled by a computer in a conventional manner. The movements of the platter and the tracing tool are intended either for mechanized tracing of pre-established drawings, or for retransmitting in the form of a drawing information pre-defined by other computers. The drawing is carried out by successive calculations from an initial initialization, there is neither free rotation of the plate, nor firm holding in any position (see FR-A2 460 025).

An advantage of the present invention is to offer manual draughtsmen a flexible, simple, fast and complete working tool for the development or manual realization of drawing, painting, illustration, engraving, tracing work (tables, plans, etc. .) cutting, assembling, gluing, coloring or other, rapid and precise movement in the free position or blocking on an angle of the document to be processed (fixed to the turntable by different known or new means in combination) compared to a rule so-called parallel or a drawing device that makes drawing gestures in general as easy as possible, including disabled designers.

To this end, the present invention relates to a drawing board, of the type comprising a fixed support on which is mounted for rotation about an axis by means of an electric motor, a movable part intended to receive a drawing sheet; said board being defined by the features of the claims below.

• la figure 1 est une vue en coupè latérale de la planche à dessiner selon l'invention,
• la figure 2 est une vue schématique d'un clavier de commande associé à la planche à dessiner de la figure 1,
• la figure 3 est une vue de dessus d'une partie de la planche à dessiner de la figure 1,
• la figure 4 est une vue en coupe latérale d'une variante de réalisation d'une planche à dessiner selon l'invention, et
• la figure 5 est une vue de dessous d'un plateau conforme à la variante de la figure 4.

The present invention will be better understood on reading the following detailed description of a preferred embodiment thereof, given by way of example and made with reference to the appended drawing, in which:

• FIG. 1 is a side sectional view of the drawing board according to the invention,
• FIG. 2 is a schematic view of a control keyboard associated with the drawing board of FIG. 1,
• FIG. 3 is a top view of part of the drawing board of FIG. 1,
• FIG. 4 is a side section view of an alternative embodiment of a drawing board according to the invention, and
• FIG. 5 is a bottom view of a tray according to the variant of FIG. 4.

Referring to Figures 2 and 3, a drawing board of the invention is in the form of a box 10. The box 10 has on its upper surface a circular opening 12 in which is received in pivoting a rotary assembly on its axis comprising a circular plate 14, on which must be fixed, by any conventional removable means, the support of the document to be processed 16. The rotary assembly further comprises a rigid ring 18 serving to support the plate 14, and supporting part of the elements necessary for the transmission of the rotary movement. The crown 18 is supported in rotation by a plurality of idle rollers 20 which are received in an uninterrupted groove 22 formed in the outer peripheral surface of the crown 18.

In addition, in the outer peripheral surface of the crown 18, below the groove 22 is also formed a continuous gear 24. The gear 24 cooperates with a toothed wheel 26 which is mounted integral with the end of the shaft of output 28 of an electric motor 30. Preferably, the motor 30 consists either of a stepping motor or of a direct current motor, and is fixed on a tilting axis 29, itself fixed to the box 10 through an appropriate support member 32.

The means for controlling the disengaging and clutch movements of the motor 30 comprise a rotary operating handle 31 which is mounted outside the box 10, being integral with a pin 72 mounted free in rotation on said box. At the end of the axis 72 opposite to the handle 31 is provided an eccentric 74 whose external surface forming a cam is capable of exerting a thrust on the motor 30 in order to separate it from the crown 18 or from the plate 14. A spring 76 allows the engine to be re-engaged.

Furthermore, the drawing board according to the present mode of embodiment of the invention comprises, with reference to FIG. 2, an electronic control unit, generally indicated at 34, which may be either integrated into the drawing board, or independent. The housing 34 has a keyboard 36 which has a number of keys 38, for purposes explained below.

Referring to Figure 3 is shown a top view of a locking mechanism of the rotary table 14, 18 of the drawing board of the present invention. This mechanism comprises a member forming a double lever 40 which is pivotally mounted about an axis 42 integral with the box 10. On one end of the lever 40 is pivotally mounted a roller 44 of automatic latching capable of cooperating by engagement with one of several notches triangular 46 formed in the outer peripheral surface of the crown 18. The lever 40 also has, adjacent to said outer peripheral surface of the crown 18, and a curvature substantially complementary thereto, a braking plate 48. lever 40 is also permanently biased, clockwise in FIG. 3, by a tension spring 50 which is mounted between fastening members 52, 54 provided respectively on the lever 40 and on the box 10. In addition, means for controlling the movements of the double lever 40 comprise a rotary operating handle 56 which is mounted outside the box 10 while being integral e of an axis 58 mounted free in rotation on said box. At the end of the axis 58 opposite the handle 56 is provided an eccentric 60 whose outer surface forming a cam is capable of urging a roller 62 integral with the double lever 40 on the same side as the point of attachment of the spring 50 by relative to the pivot axis 42 of said lever.

The operation of the drawing board as described above is as follows. The user first blocks the turntable in a desired angular position by an appropriate action on the locking mechanism using the associated handle 56. It can be noted here that this blocking can be carried out either using roller 44 cooperating with one of the notches 46, in the case of a predetermined angular position, either by means of the braking plate 48 applied against the outer periphery of the ring 18, in the case of a position any angle. The purpose of this first blocking operation is to bring the turntable into a given angular reference position, chosen for example according to the design attached to it. Then the user presses an initialization key 38d of the keyboard 36, which has the effect of zeroing an angular position memory unit contained in the electronic unit 34, a polar zero of angular reference called here "initialization" being thus created. The rotation of the rotary table is then released by an appropriate operation of the handle 56, so that neither the brake plate 48 nor the roller 44 act to block said table (intermediate position of the double lever 40).

Then the user strikes on the keyboard 36 one or more numeric keys 38e corresponding to a desired angular displacement of the table, then if necessary a validation key. The electronic unit contained in the housing 34 then acts, by means not described here as well known to those skilled in the art, to generate an electric signal for controlling the motor 30 described above from the angular information. entered using keys 38.

By first pressing the 0 key (indicated 38g) the requested angular displacement will be calculated relative to the polar zero of angular reference (initialization). Then pressing one of the + or - keys (referenced 38a and 38b respectively) the plate will be driven in one direction (38a) or in the other (38b) in rotation by the motor 30, via the toothed wheel 26 and the gear 24 in accordance with the requested angular information, from the angular position of reference 0 ° as mentioned above "initialization", then locked in this new angular position.

During work, other reference axes may be necessary. In this case one or more memorizable secondary initializations can be carried out, without losing the initial polar zero. To do this, the user types on the keyboard 36 one of the keys 38h corresponding to the desired secondary initialization. By hitting one of the keys 38i he can erase this secondary initialization.

The housing 34 will also suitably include means for effecting any relative angular rotation relative to the current angular position. For this purpose it will suffice, after a numerical value of desired angle has been entered on said keyboard (36), to directly press one of the + or - keys (without using the 0 key as previously) to thus carry out the corresponding relative angular displacement in the desired direction, from the last arbitrary positioning of the tray.

The keyboard 36 of the electronic unit may also include an erase key, in order to be able to cancel an incorrect choice of angle, as well as keys for the rapid choice of predetermined angles, such as 15 °, 30 °, 45 °. , 60 °, 75 °, 90 °, etc ... indicated at 38c in Figure 2. A step-by-step key (38f) can also be provided to refine the positioning accuracy of the turntable, each pulse corresponding to one step of the electric motor.

Means may also be provided on the electronic unit for displaying the current angular position of the table relative to the chosen angular reference position. This display, in the form of light-emitting diodes of the type with seven segments, or again with liquid crystals, is schematically indicated at 64 in FIG. 2.

It should be noted that such a current or instantaneous angular position of the table can be obtained in a simple manner either from the electrical displacement signal applied to the motor, or from the signed angle values entered by the keyboard 36, or still, for maximum precision, by means of a position sensor device of any type (opto-electronic, electromechanical, and etc.) associated with the turntable and the fixed box.

Furthermore, it is possible during use to remove the motorized control of the rotary table and to keep only the free rotation of the table without losing the memorization of the last positioning. Such an alternative embodiment is illustrated on the left-hand side of FIG. 1 and in FIG. 3. The operation of the alternative as described above is as follows: The user places the rotary operating handle 56 in the position of mechanical snap-in and brings the turntable into one of the notches 46, called here "X", by pressing one of the keys 38c. Then it disengages the motor by actuating the handle 31, then it replaces the control lever 40 in the intermediate position by an appropriate operation of the handle 56 so that the notch is released and the braking is without effect. The platform is then free of any constraints and can be operated in all the directions by simple horizontal push on the turntable. To find the motorized control, simply reverse these different operations, taking care to put yourself in the same notch called "X" before re-engaging the engine. This notch "X" can be identified at the time of choice by any mechanical, sound, light, or other means.

Furthermore, the locking mechanism may be used, in addition to the purpose of determining a desired angular reference position, each time it is necessary to block the table, that is to say in the case where mechanical forces exerted on the tray by the user may accidentally move it, to distort the accuracy of the indication of the angle and subsequent movements, that is to say in the case where the user wishes to return with maximum precision to a predetermined angular position corresponding to the 'engagement of the roller 44 of the lever 40 in one of the associated notches 46. To this end, the notches 46 may be angularly separated by 15 °, 30 °, 45 °, 60 °, 90 °, etc. as required.

With reference to FIGS. 4 and 5, another variant of a drawing table is shown, in which the rotary plate no longer remains integral with the board but can be removed, and replaced by a system of plates exactly adapted to the types of work in progress. , made of any flexible or composite material (wood, plastics, altuglass, steel, glass, etc.), which can be printed with lines, grids, templates, marks of degrees or angles, or other, which can require additional accessories for example for fixing films by nipples and which can be designed as a vacuum box for the maintenance of the working document.

This variant will be better understood on reading the following detailed description of a preferred embodiment thereof, given by way of example and made with reference to the accompanying drawings 4 and 5.

According to these figures, a drawing board according to the invention comprises a box 10, having at its upper surface a circular opening 12 in which is pivotally received a circular plate 14 rotating on its axis and on which must be fixed, by any conventional removable means, the support of the document to be processed 16. The plate 14 is shaped so as to support the elements necessary for the transmission of the rotary movement as well as the notches 46. This plate 14 is rotatably supported by a plurality of idler rollers 70 and 80. The rollers 70 located on the outer periphery of the plate 14 rotate said plate 14 on its axis while the rollers located under said plate 14 hold the latter at the upper horizontal level of the box 10.

To put on or take off the plate 14, the user places the double lever 40 in the intermediate position by action on the rotary operating handle 56, then disengages the motor 30 by action on the lever 31. Holes 82, located near the outer edge of the plate 14, allow to grasp the plate to assist in its exit. Other methods of extracting the plate can be envisaged, such as, for example, the use of an internal lever with an external handle exerting an upward thrust.

Finally, the present invention is in no way limited to the embodiment described and shown, but includes within its scope any variant or modification that may be made by those skilled in the art. In particular, the rotary table can be translucent, and the box can then advantageously include, below said table, a light source. Furthermore, it will be possible to use in the drawing board of the present invention a clearance compensation mechanism similar to that which is described and represented in French patent No. 2 155 092 by the same applicant.

We can also place on the periphery of the rotary table (crown 18 or table 14) a magnetic reading scale with the aim, via an appropriate decoder, to transmit the angle calculations to the motor, the transmission of the movement between the motor and the plate then being made by a simple roller or any gear.

In the case of use with a ruler with parallel movement, in order to overcome certain drawbacks related to the rotation of the plate (tearing off of paper, scratches, burrs, etc.) and allowing the use of documents to be treated of different thicknesses without friction between said rule and said documents, it is advantageously possible to provide an adjustable heightening of the parallel rule, for example by providing at each end of the rule bearing on the box 10, a large diameter screw, with a flat bottom to maintain the ruler parallel to the work plan, with a step such that a slight rotation causes a rapid displacement in height and whose head serving as a control button has a mark allowing to verify the identity of elevation on both sides.

Claims (2)

1. Drawing board, of type comprising a fixed holder (10) on which is mounted rotating around an axis a movable part (14) aimed to receive a drawing-sheet, a mechanical locking of this movable part being made with at least a movable roller (44) able to fit into the one of the associated notches (46) provided in the rotating part, characterized in that :

   a) the mechanical locking is accomplished by means of a mechanism with driving-haft (56) and cam (60,62)

   b) the mechanical locking is combined with a braking plate (48) designed to cooperate with the outer surface of the rotating part (18)

   c) the movable part (14) is driven in rotation by way an electric motor (30) which is equipped with a disengaging mechanism (31,72,74,76) to permit the free rotation of the rotating part (18)

   d) the rotary control of the rotating part is made by way of electronic means comprising a memory unit (34), a keyboard (36) fitted with initialization keys (38 d) and storable auxiliary initialization keys (38 h) which permit for the user to determine a rotation angle of the rotating part by means the electric motor.
2. Drawing board according the claim 1, wherein the rotating part (18) is supported in rotation by idle rollers (70,80) arranged to provide for the interchangeability of this rotating board.

Images