US2313001A - Driving mechanism - Google Patents

Description

March 2, 1943. MATHlEU I 2,313,001

DRIVING MECHANISM Filed Jan. 20, 1940 3 Sheets-Sheet l 2 fig? IFREDERIC HBTHIEU March 2, 1943.

F. MATHIEU 7 2,313,001 DRIVING MECHANISM Filed Jan. 20, 1940 3 Sheets-Sheet 2 mvEnToR= FREDERK: nmmsu BY: 551i (2 March 2, 1943. MATHlEU 2,313,001

DRIVING MECHANISM Filed Jan. 20, 1940 3 Sheets-Sheet 3 FRE'oEmc manna: yuan, fi 6;-

Patented Mar. 2, 1943 DREVING MECHANISM Frederic Mathieu, Paris, France; vested in the Alien Property Custodian Application January 20, 1940, Serial No. 314,811 In France February 18, 1939 8 Claims.

This invention is for improvements in or relating to driving mechanism for cinematograph Maltese cross projectors and has for its principal object to improve the luminosity of Maltese cross projectors by accelerating the change of the film between two images without increasing excessively the strains to which the film is subjected, nor the stresses which are applied to the different parts of the mechanism.

t is known to accelerate the change of the film by increasing and reducing periodically the speed of rotation of the Maltese cross, either by means of elliptical gears or by means of a finger-carrying plate driven eccentrically for example by means of a slide and a sliding piece.

It has also been proposed to apply force to the Maltese cross in a non-tangential manner or to use a Maltese cross with three arms.

These different devices have met with many mechanical difiiculties (vibrations, noise, rapid wear, and the like) and they have not hitherto been capable of practical employment.

Among these devices, some comprise three rotating members, the parallel axes of which are disposed in the same plane.

According to the present invention, such a mechanism is considerably improved by shifting one of the axes of rotation out of the plane of the other two.

The invention will be more particularly described with reference to the accompanying drawings, in which:

Figures 1, 2, and 3 illustrate in section the arrangement of the essential members of the driving mechanism of a Maltese cross, the first with a finger-carrying plate rotating at constant speed (ordinary Maltese cross) and the other two with a finger-carrying plate alternately accelerated and retarded by an eccentric driving device by sliding piece and slide. The Figure 2 represents a known arrangement of these members and Figure 3 an arrangement having the axis displaced according to the invention.

Figures 4 and 5 are diagrams illustrating the advantages derived by the present invention and Figures 6 and '7 illustrate a modified form of the present invention.

Referring to the drawings, a Maltese cross I is indicated as being rotated by a stud 3 about an axis 2 in the direction of the arrow F.

The stud 3 is carried by a plate 4 which in accordance with Figure 1 of the drawings is intended to be driven about the axis 5 at constant speed in the direction of the arrow F, whilst in the case of Figures 2 and 3 the plate 4 is intended to be driven at a variable speed. To this end in accordance with Figures 2 and 3 the stud 3 extends through the plate 4 and the rear extremity thereof extends with a friction fit into a cylindrical hole in a sliding'piece B. The piece 6 slides with slight friction in a diametrically arranged groove formed in a plate keyed to a spindle 8 which rotates at constant speed in the direction of the arrow F". The spindle 3 is itself driven by a train of gears, not shown on the drawings.

In Figure 2, which represents a known arrangement of these members, it will be seen that the three parallel axes 2, 5 and 8 are arranged in the plane X, Y, for example in a vertical plane.

Figure 3 shows, on the contrary, according to the present invention, one of the three axes, for example 8, displaced by a certain angle A with respect to the other two.

The advantage of the arrangement illustrated in Figure'3 will be apparent from the diagrams which are given in Figures 4 and 5.

Figure 4 represents as a function of the time (or what is the same thing, as a function of the angular position of the primary constant speed driving spindle) and for the three devices represented in Figures 1, 2 and 3, the speeds V1, V2, V3, and the respective accelerations A1, A2, A3 of the film during the rotation of the Maltese cross.

In Figure 4, V1 and A1 therefore represent the speed and the acceleration of the film in the case of Figure 1, that is to say, for a normal Maltese cross without accelerator device.

In the same figure, V2 and A2 represent the speed and the acceleration of the film in the case of the arrangement illustrated in Figure 2, that is to say, with a Maltese cross accelerated but without the axis'being'displaced. It will be seen that the speeds and the accelerations, that is to say, the forces exerted on the film, have considerably increased, which is highly injurious for this latter,

In the same figure, V3 and A3 represent the speed and the acceleration of the film with an arrangement made in accordance with the present invention (Figure 3) that is, with Maltese cross accelerated and with displacement of the driving axes.

It will be noted from the diagrams:

1. That each starting with an arrangement made in accordance with the present invention is not so sudden, not only as compared with an ordinary accelerated Maltese cross but even with an ordinary Maltese cross. This fact is indicated by the inclination of the curves of speed and of accelerations corresponding to the starting point, that is to say, at 0.

2. That the maxima positive speeds and accelerations are much less with an arrangement made in accordance with the present invention than with an ordinary accelerating Maltese cross and are scarcely greater than with the normal Maltese cross.

3. That the maximum of negative acceleration becomes, on the contrary, much more marked with an arrangement made in accordance with the present invention. But it should be pointed out that this negative acceleration corresponds to the stoppage of the film, which is helped by all the frictional forces acting on the film, in particular in the projection passage Way, in such a manner that no fatigue results from the latter. It can also be noted in this respect that a device with a'displaced aXis in accordance with the resent invention makes the curves V3 and A3 unsymmetrical, that is, reducing the positive maximum of acceleration (which corresponds to a weaker tractive effort on the film) whilst increasing to a corresponding extent the negative maximum which is not at all injurious.

This result will appear still more clearly on examining the three curves E1, E2 and E3 of Figure 5 and representing respectively the efforts which the film actually undergoes with the devices illustrated in Figures 1, 2 and 3, taking into account its friction assumed to be constant and equal to C, in the projection aperture.

As for the speeds on the preceding curves, it will be seen that the efforts E3 according to the proposed device are hardly greater than with an ordinary Maltese cross (E1) but that they are much less than with a Maltese cross accelerated without displacement (E2).

Actually the advantage due to the present invention is probably still greater than is shown on these curves owing to the fact that the friction of the film in the projection aperture is not constant but undoubtedly a little greater at the moment of detachment produced at each start, that is about the point 0. The smoother start of. the curves V1, A1 which has been pointed out abovehas therefore in reality a very great significance.

Figures 6 and '7 finally show by way of nonrestrictive example, one embodiment of a Maltese cross mechanism, accelerated and with displaced axis according to the present invention. The description of these figures will indicate certain details of construction which have proved to be very important in the operationof such an apparatus.

Figure 6 illustrates in partial longitudinal section on two parallel planes a Maltese cross mechanism, accelerated and having a displaced axis in accordance with the present invention, that is, according to the diagrammatic illustration in Figure 3.

The greater part of Figure 6 is drawn in a vertical plane containing the axis of the fingercarrying plate and the axis 8 of the slide plate. The part of the Figure 6 at the top and to the left is drawn in a plane parallel to the former but extending through the displaced axis of the Maltese cross. It is quite evident, in fact, that in practiceany desired axis could be displaced with respect to the plane of the other two.

The reference numerals employed in Figure 6 indicate corresponding members in Figures 1, 2 and 3. Thus, i represents the Maltese cross which is driven by the finger or stud 3 mounted on the plate 4 of the variable speed spindle 5. The plate i is driven by the sliding piece 6 and preferably by the extremity of the stud 3 which extends through the plate 4 or by an extension of the stud 3 from the other side of the plate. It is advisable, in fact, in order to reduce the stresses and the vibrations, to bring together as closely as possible the points of application of the driving and resisting efforts which are applied to this intermediate part. The sliding piece 6 into which the extremity of the stud 3 extends is driven by the plate 9 having a diametrically arranged slide groove, on the driving spindle 8. Owing to the fact that the axes 5 and 3 are not in line, a uniform movement of the spindle 8 results in a movement of the spindle 5 which is alternately accelerated and retarded.

A pinion H drives the spindle 8 but the remainder of the driving mechanism is not shown.

A flywheel l is rigidly fixed on to the plate of the spindle 8 and the shape and particular arrangement thereof in the interior of the mechanism will be noted. The applicant has, in fact found that in order to obtain the maximum efliciency and to achieve the greatest possible smoothness in running of the whole system, the flywheel I must be so arranged that its moment of inertia acts appreciably in the mean plane of the plate 4, which plane is shown diagrammatically by ZZ on Figure 6.

The axis 5 of the plate 4 is then preferably arranged on the same side as the Maltese cross with respect to this plate, which arrangement is somewhat important.

A frame I2 which supports the mechanism will preferably be sufficiently robust in order to offer a sufiiciently great inertia against vibrations.

The flywheel 7 is preferably made of bronze in order to have a large mass in a reduced volume.

The groove plate 9, like the spindle 8, the stud 3, and the majority of the parts of the mechanism, are made in steels of suitable kind and temper. The locking slope lil of. the Maltese cross is, as usual, of cast iron.

The sliding piece 6 is preferably of celeron a material often used for high speed gears, or of some similar material which has both the property of being very resistant to wear and of dampening in a very efiicient manner vibrations, in consequence of great internal dampening.

Finally, it will be noted that there are shown on Figures 6 and 7 certain particular lubricating devices which have been found very efficient for the good operation of the mechanism forming the object of the invention.

Thus, the spindle 5 is hollow over a portion of its length in order to bring the oil under pressure directly on to the locking slope of the Maltese cross through the medium of a radial conduit made in the core of this slope.

The oil under pressure delivered at l! to the frame of the apparatus, collects first of all in a collecting chamber l3 from whence it penetrates into the hollow axis 5 through the holes I4. It thus passes at [5 to the locking slope of the Maltese cross and at It opposite the sliding piece 6.

Figure 7 shows in particular the delivery of oil under pressure at IE on to the locking slope. The presence of this oil under pressure at the moment when the two surfaces come into contact forms a dampening cushion which greatly improves the smoothness of running.

It must be understood that the mechanical arrangements which are shown with reference to Figures 6 and 7, are applicable not only to accelerated Maltese cross arrangements, with displacement of the driving axes (according to Figure 3), but also to Maltese cross devices simply accelerated but without displacement of axis (Figure 2), and even as the greater part of them, to ordinary Maltese cross devices (Figure 1).

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a locking slope, the combination of a slide groove plate of relatively greater diameter than that of said finger-carrying plate and the latter plate being at least for the most part disposed within the area or outline of the slide groove plate, an elongated sliding piece in the slide groove of the plate engaging the finger of the finger-carrying plate, a driving spindle of the slide groove plate operable at constant speed, one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

2. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a locking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plate of relatively greater diameter than that of said finger-carrying plate and the latter plate being at least for the most part disposed within the area or outline of the slide groove plate, and elongated sliding piece in the slide groove of the plate engaging the finger oi the finger-carrying plate, a driving spindle of the slide groove plate operable at constant speed, one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes, and the fingercarrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

3. In a film conveying device for cinematograph projectors, having a Maltese cross, a driving finger, a finger-carrying plate having a locking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plate of relatively greater diameter than that of said finger-carrying plate and the latter plate being at least for the most part disposed Within the area or out- 1ine of the slide groove plate, an elongated sliding piece in the said slide groove carrying the axis of the finger-carrying plate, a driving spindle of the slide groove plate operable at constant speed, one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes, and the axis of the fingercarrying plate being arranged on the same side of the said plate as the axis of the Maltese cross, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

4. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a looking slope, the said finger carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of th said finger-carrying plate, the combination of a slide groove plate and an elongated movable slide piece, said finger also extending into said movable slide piece in a diametrical slide groove of said slide groove plate integral with the driving spindle of constant speed of the whole system, said slide groove plate being of relatively greater diameter than that of said finger-carrying plate and the latter plate being disposed at least for the most part within the area or outline of said slide groove plate, and one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes, and the fingercarrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

5. In a film conveying device for cinematograph projectors, having a Maltese cross, a driving finger, a finger-carrying plate having a locking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plate and an elongated movable slide piece, said finger also extending into said movable slide piece in a diametrical slide groove of said slide groove plate integral with the driving spindle of constant speed of the whole system, said slide groove plate being of relatively greater diameter than that of said finger-carrying plate and the latter plate being disposed at least for the most part Within the area or outline of said slide groove plate, and one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes and a flywheel integral with the slide groove plate and having the driving spindle arranged about the finger-carrying plate, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

6. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a locking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plateand an elongated movable slide piece, said finger also extending into said movable slide piece in a diametrical slide groove of said slide groove plate integral with the driving spindle of constant speed of the whole system, said slide groove plate being of relatively greater diameter than that of said finger-carrying plate and the latter plate being disposed at least for the most part within the area or outline of said slide groove plate, and one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes and a flywheel integral with the slide groove plate and having the driving spindle arranged about the fingercarrying plate, the finger, the spindles and the slide groove being formed of steel, the flywheel of bronze and the sliding piece of celeron or similar material, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

'7. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a looking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plate and an elongated movable slide piece, said finger also extending into said movable slide piece in a diametrical slide groove of said slide groove plate integral with the driving spindle of constant speed of the whole system, said slide groove plate being of relatively greater diameter than that of said finger-carrying plate and the latter plate being disposed at least for the most part within the area or outline of said slide groove plate, and one of the three axes of the Maltese cross, of the finger-carrying plate and of the slide groove plate being disposed externally of the plane of the other two axes and a flywheel integral with the slide groove plate and having the driving spindle arranged about the fingercarrying plate, the finger, the spindles and the slide groove being formed of steel, the flywheel of bronze and the slide piece of celeron or similar material and there being means for applying lubrication under pressure to the mechanism in particular to the locking slope of the Maltese cross, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

8. In a film conveying device for cinematograph projectors having a Maltese cross, a driving finger, a finger-carrying plate having a looking slope, the said finger-carrying plate being driven directly by the extremity of the finger of the Maltese cross which is extended to the other side of the said finger-carrying plate, the combination of a slide groove plate and an elongated movable slide piece, said finger also extending into a movable slide piece in a diametrical slide groove of said slide groove plate integral with the driving spindle of constant speed of the whole system and said slide groove plate being of relatively greater diameter than that of said finger-carrying plate and the latter plate being disposed at least for the most part within the area or outline of said slide groove plate, and a flywheel integral with the slide groove plate and with the driving spindle being arranged about the finger-carrying plate, the finger, the spindles and the slide groove being formed of steel, the flywheel of bronze, and the sliding piece of celeron or similar material, and the finger-carrying plate being distinct from the Maltese cross and the elongated slide piece and disposed in a plane intermediate said Maltese cross and slide piece.

FREDERIG MATHIEU.

Images