FR2627869A1 - LIGHT BOX FOR PROJECTION APPARATUS, AND PROJECTION APPARATUS COMPRISING SUCH A LIGHT BOX - Google Patents

Abstract

This is a light box of the kind comprising a sole 10 on which is movably mounted a carriage 11 carrying a lamp support 12, with, for a positive definition of the position of the latter, two stops, one for which a first of the lamps 14A, 14B is in service, the other for which the other of these is in turn. According to the invention, these two stops are each individually mounted and adjustable in position with respect to the support sole 10, under the control of separate commands 22A, 22B available to the operator at the rear of the light box. Application to projection apparatus for slides.

Description

"Light box for projection apparatus, and projection apparatus

  The present invention generally relates to projection apparatuses of the type used for projection onto a screen of fixed views, commonly referred to as slides, and more particularly to the part of these projection devices, commonly called light box, specific to the emission of the light beam

  necessary for such a projection.

  In the usual way, this light box comprises, generally, a support sole on which is mounted movably, transversely to the projection axis, a carriage carrying a lamp holder having at a distance one of the another two lamp locations each adapted to receive a projection lamp, with, for a positive definition of the position of said carriage, two stops, namely a first stop, here referred to simply as a service stop convenience, for which a first of said locations lamp is perpendicular to said projection axis, and, at a distance from this first stop, a second abutment, here referred to simply as a relief abutment convenience, for which the second of said

  lamp is in turn in line with this axis of projection.

  Thus, the service stop being retractable for this purpose while the carriage carrying the lamp holder is permanently solicited, by elastic means, in the direction of the abutment stop, it is possible, in case of failure in progress of projection, to immediately substitute one lamp for another, which limits at best

  the interruption of projection due to such a failure.

  Various problems arise, however, with

light boxes of this type.

  The first relates to the need to ensure, both for the service lamp and the emergency lamp, precise position

the projection axis.

  To date, this position adjustment is most often on the lamp holder itself, it being for this purpose made mobile and adjustable in position on the

carriage that carries it.

  It follows firstly that, by construction, this position adjustment jointly affects the one and the other of the two lamp locations that has such a lamp holder, since they are jointly integral with it. However, in view of the inevitable manufacturing tolerances, a correct position adjustment for the service lamp is not necessarily suitable for the emergency lamp, this position adjustment having to take into account the

filament of these lamps.

  It also results from a position adjustment occurring on the lamp holder, that, to perform such a position adjustment, it is necessary to have access to this lamp support, and thus to open, on top of it, the device projection, at the risk of being dazzled by the lamp in use, since, taking into account its filament, the position adjustment of such a lamp can only be done while

it is illuminated.

  Such a position adjustment is therefore both unsatisfactory, since it can only really wear on one of the lamps, and inconvenient, since it must be done

over and in full light.

  According to a first aspect, the subject of the present invention is a provision making it possible to avoid these disadvantages. In this regard, the light box according to the invention, which is of the kind comprising a support sole on which is mounted movable, transversely, relative to a projection axis, a carriage carrying a lamp holder having remote from each other two lamp locations, each of which is adapted to receive a projection lamp, with, for a positive definition of the position of said carriage, two stops, namely a first stop, referred to as a service stop, for which a first of said lamp locations is in line with said projection axis, and, at a distance from this first stop, a second, so-called backup, for which the second of said lamp locations is in turn vertically in line with this axis of projection , is generally characterized in that said stops are each individually mounted adjustable in position relative to the support sole, under the control of separate commands at the disposal of

the operator.

  Thus, by intervening, according to the invention, no longer on the support of lamps, but on the stops which ensure the positioning, it is advantageously possible to adjust, independently of one another, the two positions, the one of service, the other of relief, of this

lamp support.

  In addition, it is advantageously possible to make accessible from the outside, at the back of the box to

  light, one and the other of the corresponding commands.

  Thus, according to this first aspect of the invention, the lamps are adjustable in position independently of one another, and the corresponding settings can very easily and quickly be made from the outside of the same.

  the projection apparatus, sanris opening of it.

  A second problem with the light boxes is that, the lamp holder being pivotally mounted on the carriage that carries it, it must be able to tilt outward, which presupposes beforehand

  unlocking with respect to this cart.

  According to a second aspect, the present invention also relates to a provision making it possible to facilitate

the corresponding operations.

  According to this aspect, the light box according to the invention is, in general, characterized in that the emergency stop belongs to a pivotally mounted lever, and in that said lever comprises, at a distance from this emergency stop , a third stop, specific to the positive definition of a third position for the carriage

carrier of the lamp holder.

  For this third position of the carriage which

  door, the lamp holder is unlocked.

  In practice, for cooperation with these stops, this carriage comprises an arm, and, for the passage from its second position to its third, it is slidably mounted on this arm, against elastic return means, a pull, who is at the disposal of the operator, and who

  has a cam adapted to the retraction of the lever concerned.

  Thus, a simple pull on this zipper ensures the unlocking of the lamp holder, and this unlocking however advantageously requires a voluntary maneuver on the part of the operator, which eliminates any risk of

  unlocking accidentally or inadvertently.

  A third problem with light boxes is that, in case of failure of one of its components,

  it must usually be changed in its entirety.

  The maintenance of such a box-light is found

weighed down so much.

  According to a third aspect, the present invention also provides a provision for minimizing

this disadvantage.

  According to this aspect, the light box according to the invention is further characterized in that, on its support sole is reported, separately, in elevation relative to the carrier carriage of the lamp holder, an optical box grouping all his

optical components.

  Thus, in the event of a defect, only the support sole can be advantageously changed without any joint change in the optical components, even though this support sole, which together with the constituents it carries, forms the functional part of the box. light, is also the most sensitive part of such defects. The cost of maintaining the following light box

  the invention is minimized accordingly.

  The present invention of course still relates to any projection apparatus comprising such a box

to light.

  The features and advantages of the invention

  from the following description,

  for example, with reference to the accompanying schematic drawings in which: Figure 1 is an elevational view of the light box according to the invention, along the arrow F1 of Figure 2; Figure 2 is a general view, in exploded perspective, of this light box, which, however, have been eliminated some of the optical components; 3 is, according to the arrow F3 of FIG. 2, a fragmentary exploded perspective view of some of the constituents of this light box; FIG. 4 is, on an upper scale, an elevational view along the arrow '; F4 of Figure 3, one of the eccentrics implemented in this light box; Figure 5 is, along the arrow F5 of Figure 1, a partial view, in perspective, of other components of the light box according to the invention; Figures 6, 7 and 8 are elevational views, which, similar to that of the figure, each illustrate respectively the various possible positions for the

  lamp holder in this light box.

  As illustrated in these figures, and as is best seen in Figure 2, the light box according to the invention comprises a support sole 10 on which is movably mounted, transversely to a projection axis A, a carriage 11 carrying a lamp holder 12 having at a distance one from the other two lamp locations 13A, 13B each adapted to receive a projection lamp 14A, 14B, and on which is jointly reported , distinctly, according to one aspect of the invention, in elevation with respect to the carriage 11 above, and according to the modes described in more detail later, an optical box 15 grouping all the

optical components needed.

  The carriage 11 extends, in practice, in the median zone of the support sole 10. At the rear, the orientation being taken along the axis of projection A, this support sole 10 comprises, perpendicular to it same, a flange 16, which, at its base, is perforated by a slot 17, and which, along its free edge, is bordered parallel to the support sole, and in the same direction as this one, by a back in

square 18.

  For a positive definition of the position of the carriage 11 with respect to the support flange 10, at least two abutments are provided, namely a first abutment A, here referred to simply as a service abutment convenience, for which, as shown in FIG. 1, a first, 13A, of the lamp locations 13A, 13B, is in line with the projection axis A, and, at a distance from this first stop 20A, a second abutment 20B, referred to here as a simple Convenience abutment relief, for which, as shown in Figure 6, the second, 13B, of these lamp locations 13A, 13B, in turn is in line with this axis of projection A. According to the invention, the stops 20A, 20B, which are visible in FIG. 3, are each mounted individually adjustable in position relative to the support soleplate 10, under the control of distinct commands 22A, 22B, which, at the disposal of the operator, are accessible from outside the light box, at the back era of

it.

  In practice, the service stop 20A and the emergency abutment 20B are each individually carried by two separate plates 23A, 23B, which, mounted parallel to themselves on the support sole 10, under the control of the controls 22A , 22B associated, are superimposed on each other, in contact with the inner face of the flange 16 of the support plate 10, the plate 23A

  intervening between it and the plate 23B.

  At its base, cfiacune of these plates 23A, 23B has, in its median zone, a notch 24 by which it is able to envelop the slot 17 of the flange 16 of the

support sole 10.

  At the edge of this notch 24, the plate 23A has, on the one hand, in the median position, a notch, and, on the other hand, in a lateral position, a tab 26, which, for example resulting from a burst, makes protruding forward. On the edge of its notch.24, the plate 23B has, in lateral position, for the passage of the leg

  26 previous, an indentation 28.

  At its upper part, each of the plates 23A, 23B presents, aligned parallel to the support soleplate 10,

three openings.

  First, in the central position, for the passage of a gun 29 carried, parallel to the support sole 10, by the flange 16 thereof, a central opening 30, which, identical for the one and the other of the plates 23A, 23B is lengthened in parallel buttonhole

said support sole 10.

  There is then, in lateral position, for the intervention of the corresponding control 22A, 22B, a

  lateral opening 32, circular contour.

  From plate 23A to plate 23B, the position of

this opening 32 is reversed.

  Finally, in the lateral position, opposite the previous opening 32, an opening 33, which is identical for both of the plates 23A, 23B, being, for each of them , substantially disposed at the right of the opening 32 of the other, is lengthened in buttonhole

  perpendicular to the support sole 10.

  The service stop 20A belongs, in practice, to a lever 35A, which, pivotally mounted on the corresponding plate 23A, is under the control of a control electromagnet 36 carried by the right angle return 18 of the flange 16

of the support sole 10.

  This lever 35A is disposed on the other side of the plates 23A, 23B with respect to this flange 16, and it comprises, generally at right angles to one another, two arms, namely, on the one hand, an arm 37, which, on one side, is articulated, thanks to the notch 28 of the plate 23B, to the tab 26 of the plate 23A, by an axis 38A provided for this purpose, and which, of the on the other hand, has a notch forming the service stop 20A, and, on the other hand, an arm 40, which, by means of a cut-out 41 of the angular return 18 of said flange 16, extends to the right of the nqyau diver 42 from

the control electromagnet 36.

  The emergency stop 20B belongs, for its part, to a lever 35B, which also extends on the other side of the plates 23A, 23B relative to the flange 16 of the support soleplate 10, being pivotally mounted, by an axis 38B provided for this purpose, on the plate 23B, and which has a notch

forming the abutment 20B.

  As it is easy to understand, the notch

  platinum 23A prevents the axis 38B as well.

  carried by the plate 23B interferes inadvertently

with this turntable 23A.

  According to one aspect of the invention, the lever 35B comprises, at a distance from the emergency abutment 20B, and in the form, like this one, a notch, a third abutment 20C, also specific to the definition positive of a third

  position for the carriage 11 carrying the lamp holder 12.

  In practice, the notch of the lever 35B forming this stop 20C has a height much greater than that of the notch

forming the abutment 20B.

  The levers 35A and 35B, whose notches forming an abutment extend on the same side relative to their hinge axis, are jointly subjected to resilient return means of a nature to permanently solicit

  these notches towards the support sole 10.

  In the embodiment shown, these elastic return means are constituted by a torsion spring 45, whose central portion of torsion 46 is engaged on the barrel 29, and whose lateral wings 47A, 47B bear, respectively, respectively on expected returns to

this effect on the levers 35A, 35B.

  The controls 22A, 22B controlling the position of the stops 20A, 20B are in the general form of studs which, beyond a head 48 by which they bear on the plate 23B, the side thereof opposite the flange 16 of the support plate 10, comprise, successively, and as it is better visible for one of them in Figure 4, firstly, an eccentric 49, by which they are adapted to act on the platinum 23A, 23B corresponding, through the opening 32 thereof, bearing on the edge of this opening 32, and a barrel, by which they project on the outer face of said

flask 16.

  On its end edge, this barrel 50 has, diametrically, in the manner of a screw head, a groove specific to the control in rotation of the controls 22A, 22B

thus constituted.

  A slotted washer 51, engaged with it, ensures the

maintenance of these.

  As is easily understood, a rotation, in one direction or the other, of any one of the controls 22A, 22B causes a linear displacement, in one direction or the other, parallel to it. - Same, and parallel to the support plate 10, according to the double arrow F6 of Figure 3, the plate 23A, 23B concerned, and therefore by it, the stop 20A, 20B which is secured by lever 35A, 35B

corresponding.

  For cooperation with the stops 20A, 20B, 20C, the carriage 11 comprises, in the direction of the flange 16 of the support soleplate 10, an arm 52, FIGS. 3 and 5, and on this arm 52 is slidably mounted, against elastic return means constituted by a spring 53, a pull tab 54, which is at the disposal of the operator, and which comprises a cam 55 suitable for the retraction of the lever 35B

  to which belongs the emergency abutment 20B.

  In practice, the pull tab 54, which protrudes out of the light box thanks to the slot 17 provided for it at the base of the flange 16 of the support soleplate 10, has, laterally, two flanges 56, through which it frames the arm 52 of the carriage 11, and on the section of the one

  of which is formed the corresponding cam 55.

  As for the spring 53, it is coupled between, on the one hand, a tab 57 coming from this arm 52, and, on the other hand, a tab 58, which, coming from the pull tab 54, passes through this arm 52 to

  the favor of a buttonhole 59 thereof.

  As best seen in FIG. 5, the carriage 11 has, on the one hand, a sole 60, by which it is slidably mounted on the support sole, this sole 60 having projecting downwards, as shown in FIG. visible in Figure 2 for one of them, pins 62 engaged with a buttonhole 63 of the support sole 10, and, secondly, articulated by an axis 64 on this sole

  , a flip-flop 65 carrying the lamp holder 12.

  It's from. the sole 60 that the arm 52 comes from.

  Opposite this arm 52, and therefore opposite the abutments 20A, 20B, the carriage 11 has, also coming from its sole 60, an arm 66 through which, as diagrammatically shown in broken lines in FIG. he is fit to

  actuating at least one microswitch 67.

  In the embodiment shown, two microswitches 67 are thus provided on the path of this arm 66, each being respectively arranged on each side.

  other than a point-shaped return 68 thereof.

  According to arrangements which, not falling within the scope of the present invention, will not be described in detail here, these microswitches 67 may for example be used at various internal controls to the projection apparatus concerned. The lever 65 is secured to a lever 70, which is intended to allow the control tilt, and which has, laterally, projecting a pin 71 to engage, for locking.de all, under a back to square 72 of the support plate 10 when the carriage 11 is in one or other of its positions defined by the service stop 20A and the emergency stop B. By a spring 74, visible, in particular, to 2, to which it is coupled, and which, at its other end, is coupled to a lug 75 secured to the support sole 10, the carriage 11 is permanently biased towards the

stops 20A, 20B, 20C.

  The lamp holder 12 that carries the carriage 11 is well known per se, and not part of the present invention, it will not be described here otherwise than to indicate that, as already mentioned above, it present, spaced apart from one another, two lamp locations 13A, 13B. The preceding constituents form, taken as a whole, an active part of which is advantageously differentiated, according to an aspect of

  the invention, the part, more passive, that forms the box.

associated optics

  In the embodiment shown, this optical box 15 is spaced apart from the support soleplate 10 by tubular spacers 76, and it is attached to it by means of threaded rods 77 which, passing through these tubular spacers 76, cooperate with each other. , beyond the

  support sole 10, with nuts 78.

  In the embodiment shown, the optics box 15 has, internally, a corridor 79, in which the carriage 11 carrying the lamp support 12 runs, with, on a first side of this corridor 79, in this case the side-rear thereof, a wall 80 carrying, facing forwards, a mirror 81, in this case a spherical mirror, and on the other side, and therefore on the front side, a compartment 82 containing all the other optical components -needed. In practice, the mirror 81 is carried by a flange 83, which, mounted on the rear face of the partition 80, is mounted height-adjustable thereon under the control of an eccentric control 84 whose barrel 85 is disposed in the alignment of the barrel 29, so that, like the controls 22A, 22B, this eccentric control 84 is thus accessible from the outside of the light box, to

the back of it.

  The compartment 82 extends between two partitions 86, which, parallel to the previous partition 80, are each

perforated with a recess 87.

  Between these two partitions 86 extend, in the manner of drawers, in favor of flat 90 provided for this purpose both on the floor 91 of the compartment 82 and on its roof 92, intermediate partitions, not shown in the figures, carriers each of an optical component, such as condenser, filter, or lens, also not visible on

the figures.

  Preferably, the corresponding drawers are associated ratchets adapted to ensure blocking in position in the compartment, 82, to avoid the fall

  during manipulation of the optical box 15.

  In use, and under the stress of the spring 74, the carriage 11 carrying the lamp holder 12 is normally supported, by its arm 52, and, more specifically,

  by the edge thereof, against the service stop 20A.

  It is therefore normally the lamp 14A which, then arranged along the projection axis A, between the mirror 81 and the compartment 82 of the optical boot 15 is in use. If this lamp 14A is to fail, an excitation of the control electromagnet 36 suffices, by the actuation of the lever 35A which results, to cause the release of the carriage 11, which then escaping the stop by this lever 35A, is itself applied against the stop 20B carried by the lever 35B, the latter being

interposed on its way.

  For the position occupied by the carriage 11, FIG. 6, it is the lamp 14B which is in turn disposed along the projection axis A, and this lamp 14B

  thus substitutes itself for the lamp 14A failed.

  As explained above, the precise adjustment of the corresponding positions of the carriage 11, and therefore of the lamps 14A, 14B with respect to the projection axis A, is advantageously made from the back of the light box, at the

  favor of the corresponding commands 22A, 22B.

  For change of the defective lamp 14A, it

  it suffices for the operator to act in traction on the pull tab 54.

  By its cam 55 it then causes the lifting of the lever 35B in an amount sufficient for that escaping

  at the stop 20B that it carries, the carriage 11 comes from -

  itself, under the solicitation of its return spring 74, apply on the abutment 20C that this lever 35B carries to the

  T5 following the previous stop 20B.

  For the new position, Figure 7, which is that of the carriage 11, the lug 71 of the lever 70. carried by it escapes the return 72 of the support plate 10, so that, as shown in FIG. 8, the lever 65 of this carriage 11 can, with the aid of this lever 70, which is then projecting out of the optical box 15, be tilted

  vertically, giving access to the lamp support.

  12, and therefore to each of the lamps 14A, 14B.

  After changing the defective lamp, simply reset the scale 65, then, using the pull tab 54, but without acting in tension on it, to

  return to its initial position the carriage 11.

  Of course, the present invention is not limited to the embodiment described and shown, but

  encompasses any variant of execution.

Claims (12)

  1. A light box for projection apparatus, of the kind comprising a support base (10) on which is mounted movably, transversely with respect to a projection axis (A), a carriage (11) carrying a lamp support. (12) having at a distance from each other two lamp locations (13A, 13B) each adapted to receive a projection lamp (14A, 14B), with, for positive definition of the position of said carriage (11) , two stops (20A, 20B), namely a first stop (20A), said service, for which a first of said lamp locations (13A) is in line with said projection axis (A), and remotely of this first stop (20A), a second abutment (20B), called relief, for which the second of said lamp locations (13B) is in turn vertically above this projection axis (A), characterized in that that said stops (20A, 20B) are each individually mounted adjustable in position relative to the sole of sup port (10), under the control of. separate orders (22A, 22B) the layout of the operator.   2. A light box according to claim 1, characterized in that the service stop (20A) and the emergency stop (20B) are each individually carried by two separate plates (23A, 23B) mounted parallel to themselves on the support sole (10)   under the control of the associated commands (22A, 22B).   3. A light box according to claim 2, characterized in that the two plates (23A, 23B) are superimposed on each other.   4. Light box according to any one of   Claims 2, 3, characterized in that the controls   (22A, 22B) comprise an eccentric (49) by which they are adapted to act on the corresponding plate (23A, 23B)   in favor of an opening (32) thereof.   5. Light box according to any one of   Claims 1 to 4, characterized in that the commands   (22A, 22B) of the one and the other stops (20A, 20B) are accessible from the outside, at the rear of the light box. 6. Light box according to any one of   Claims 1 to 5, characterized in that the stop of   device (20B) belongs to a lever (35B) pivotally mounted, and said lever (35B) comprises, at a distance from this abutment (20B), a third abutment (20C) suitable for the positive definition of a third position for the trolley   (11) carrier of the lamp holder (12).   Light box according to Claim 6, characterized in that the carriage (11) carrying the lamp holder (12) has, for cooperation with the stops (20A, 20B), an arm (52), it is mounted sliding, on this arm (52), against elastic return means (53), a pull (54), which is available to the operator, and which comprises a cam (55) specific to the retraction of the   lever (35B) to which the emergency stop (20B) belongs.   8. Light box according to any one of   Claims 1 to 7, characterized in that the stop of   service (20A) belongs to a lever (35A) which, pivotally mounted, is under the control of an electromagnet of control (36).   9. Light box according to any one of   Claims 1 to 8, characterized in that, unlike   stops (20A, 20B, -20C) able to positively define the position, the carriage (11) carrying the lamp support (12) has an arm (66) by which it is adapted to actuate from minus a microswitch (67) carried by the support sole (10).   10. Light box according to any one of   Claims 1 to 9, characterized in that on the sole   of support (10) is distinctly raised in relation to the carriage (11) carrying the lamp support (12), an optical box (15) gathering all its optical components.   11. A light box according to claim 10, characterized in that the optical box (15) comprises, 16- internally, a corridor (79) in which the carriage (11) carrying the lamp holder (12) circulates, with on one side of said corridor (79), a partition (80) carrying a mirror (81), and on the other side a compartment (82) containing all the other optical components. 12. Projection apparatus characterized in that it comprises a light box according to any one of claims I & 11.