Patent GB-936102-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B7/16
Filed: 1960-07-14
Abstract: 936,102. Photographic cameras. BELL & HOWELL CO. July 14, 1960 [Oct. 12, 1959], No. 24528/60. Class 98 (1). A photographic camera includes an objective, a diaphragm having a variable aperture, an automatic diaphragm control device for varying the diaphragm aperture, first manually movable means having an indicator member which cooperates with stationary indicia on the camera housing to indicate distance, second manually movable means having flash guide number indicia thereon, said second manually movable means being movable relative to the first manually movable means, said second manually movable means being movable between an operative range for manual over-ride of the diaphragm control device and an inoperative position disconnected from the diaphragm control device, said first and second manually movable means having interengaging means for selectively coupling said second manually movable means to said first manually movable means in any one of a number of relative positions in said operative range of said second manually movable means, and means on said second manually movable means adapted to engage a member mounted for movement with said diaphragm control device for driving said diaphragm control device when said second manually movable means is in its operative range. As shown (Fig. 2), an objective tube 24 has a pin-and-slot coupling 25, 24a with a support member 21b screwed to the front wall 21a of the camera for providing focusing movement of the objective 23 when said tube 24 is manually rotated. Connected to the tube 24 by means of a rack and pinion coupling 31, 24c is a slide 33 (said first manually movable means) which moves in a slot 21d in the wall 21a and carries an index mark 33b for indicating the focus setting against a distance scale on a cover panel 36. The diaphragm and automatic control device comprise two diaphragm discs 42, 43 (Figs. 2 and 4) which are respectively pivoted about pins 46, 47, have overlapping slit apertures 42a, 43a and have toothed portions 42b, 43b in mesh with a pinion 51 which rotates with the moving coil of an exposure meter, the photo-cell of which is mounted in the view-finder. The pinion 51 is biased in the anti-clockwise direction (Fig. 4) towards a position corresponding to maximum diaphragm aperture. A further slide 65 (said second manually movable means) is mounted in a slot 21k in the wall 21a, and, when it is desired to take flash photographs, said slide 65 may be selectively locked for common focusing movement with the slide 33 by means of a spring-urged detent member 67 which is pivotally mounted on the slide 65 and has teeth 67c engageable with corresponding teeth 33d in the slide 33. The slide 65 is also coupled by way of a pin and slot connection 61c, 63a (Fig. 6), with a cam lever 61 (cf. also Fig. 5, not shown) which is pivoted at 62 and has a cam portion 61a which is engaged by a pin 51a on the pinion 51 and thereby sets the diaphragm aperture according to the focus setting. Detent 67 bears a flash guide number scale 67e which may be set against the index mark 33b for taking account of type of flash bulb and film sensitivity. When it is not desired to take flash photographs the automatic diaphragm is allowed to operate freely by breaking the coupling between the slides 33 and 65, this being accomplished by manually pivoting the detent 67 out of engagement with the slide 33, sliding the detent 67 and member 65 to their end positions corresponding to maximum diaphragm aperture, and then allowing further wide teeth 67g (Fig. 8) in the detent 67 to engage with correspondingly wide teeth 21n provided in the wall 21a. Light and dust are prevented from entering the apertures in the front wall 21a by means of cover-plates 34 and 66 which are fixed respectively to the slides 33 and 65. The camera is provided with an attachment point 19 for a flash gun and two eletrical contact points 18. A transparent protective cover 71 (Fig. 9) may be pivotally mounted on the panel 36 by means of an overcentre spring connection. The lens mount 24 may be provided with indicia at 24b for further indicating the focus setting. The lower portion of the plate 67 may have an index for cooperation with an f-number scale on the panel 36 whereby manual setting of the diaphragm may be obtained.