US1716512A - Photographic shutter - Google Patents

Description

Juhell, 1929. w. IAUERSFELD ET AL 1.716.512

PHOTOGRAPHI'C SHUTTER Filed larch 30, 1928 e7 n 2 t:::::;::::: I 2 i v a I \M u pluL L Fig. 4 b Jwentons:

' The shutter shown contains 45 worm i,

- Patented June 11', 1929.

wALTmm BAUEBSFELD AND FRANKLIN PFEIFFEB, or TO THE FIRM CARL ZEISS, or JENA,

JENA, GERMANY, ASSIGNORS GERMANY.

V PHOTOGRAPHIC SHUTTER.

Application ma March-30, 1928, Serial No.

' The present invention relates to photographic shutters, which are to be disposed at the locus of't'he camera objective and wlnch contaih a plurality of rotatable shutter 5 blades, partly overlapping each other. The invention corisists in this that with these shutters :the blades are. constructed as spherical bowls,and not, as heretofore, as plane discs. Thereby-one attains in the first lacea great rigidity of the blades, so as to able to render them particularly thin; moreover, a very compact structure of the shutter is thereby attained.

The annexed drawing shows as an example a shutter according to the invention.

Fig. 1 represents a section through the shutter along the objective axis. Fig.- 2 a perspective view of the shutter with the casing removed, looking in the direction of the arrow shown in Fig. 1, Fig. 3 a front view of one of the shutter blades and Fig. 4 a section on theline 4-4 of Fig. 1.

four blades a, recessed according to Fig. 3 and constructed as spherical bowls, which are rotatably supported on'a spherical casing b with axes c. On the latter are fixed driving wheels (1, engaging in a gears of 'a'bevel wheel erotatable about the casing b. The bevel wheel has also a second gear a, coacting with a curved wheel f, which is rotatably supported on the casing by means of an axis g. On the wheel f there are fixed two ratchet wheels f and f. By means of two ratchets h and b engagin these wheels, the latter and also the eel f are coupled to a spring casing 2' on which the ratchets are fixed rotatable about an axis h, The spring casing is likewise rotatable about the axis 9 and within'the same 40 there is so ported a spirial spring 2'. The

one end o this spring is fastened in the spring casing z', whilst the other is rigidly connected to a worm wheel 1', rotatable about the axis g. The worm wheel meshes with a which is supported .on a standard fixed on the base I) of the casing and provided with a milled head i. The spring casing carries in addition a handle 2', two noses i and iand a stop 2', which during clock- 7 wise rotations'of the spring casing strikes against a plate 7', fixed on the standardj. Between the worm wheel 2' and the spring casing i there is disposed a spur wheel k, which is rigidly connected to the worm wheel provided a spherical body 12-, to receive a part of the 266,072, and in Germany February 8, 1926.

2' and engages in a wheel 70 The latter is supported on a standard [a fixed on the base plate 6 and engages in a toothed sector Z, which is rotatable about a bolt Z fixed on the spherical part of the casing b. On the bolt is fixed a spring casing Z in which is disposed a spiral spring Z the one end of which is fixed on the nave of the toothed sector I. The other end of the spring is free and extends below the nose 2" of the spring casing 2'. To the casing b of the shutter there is also rigidly connected a pin m which serves for releasing the ratchet 1L Besides there is which is destined photographic objective, whilst the other part of the objective'is to be fixed on the casing itself. In addition, there is provided a disengaging friction brake for the wheel f whose friction disc is formed by the wheel i. As a brake shoe serves the head 0 of a rod 0, which is guided in a sleeve 0 fixed on the base plate I), and which rod is under the action of a spring 0 The sleeve 0 has a slot 0. through which passes a pin 0", fixed on the rod 0 The pin 0 extends behind a pawl 12 to be released by hand and being under the action ofa spring p, which is supported on the base plate I) at a standard p All actuating parts of the shutter are covered by a lid N.

The operation of the shutter takes place in the following we The shutter is to be wound up by rotating clockwise the spring casing Thereby the latter is rotated by means of the handle i until the stop i strikes against the plate 7' in which case the pawl facts behind the nose 2'", so as to prevent the spring casing from turning back. On rotating the spring casing the ratchet k slips along the pin m, viz, in the first place with a part concentric with the axis of rotation g of the spring casing, so that the position of the ratchet it does not undergo a change. Consequently, the ratchet remains in mesh with the ratchet Wheel 7, and the latter with the wheel 7 as well as the bevel wheel e, the driving wheels d and the blades a are turned backwards together with the spring casing. The arrangement is such that the blades a are thus rotated in a backward direction through 60. After the rotation of the spring casing 2', corresponding to the aforesaid angle, the ratchet It comes to lie under the pin m with a part projecting beyond that part of it which is concentric with its axis of roleases the wheel 7. At the same time there is released the nose 2' and the spring casing i jerks back into its original position. Thereby the ratchet if rotates the ratchet wheel f and the blades a; these latter are rotated through 420. so that they resume that position which they held prior to the winding-upot'thc shutter. During the rotation of the blades a through 420 all. recesses of the blades come to lie simultaneously in front of the lenses ot-the objective. whereby the shutter is at full aperture. However, the opening does not begin simultaneously with the jerking back of the spring casing but only after the latter and all parts to be moved have been moved somewhat. Thereby it is attained that during the proper opening-period the blades (0 move at a uniform speed and need not first be accelerated during this period. At the end of the opening period the nose '5 strikes against the free end of thespiral spring Z" by which-a shock atthe end of the motion of the blades is prevented. In order that sufiic-ient ranges for the initial acceleration for the opening-period and for the gradual standstill ot the masses are available, one. has chosen the comlniratively large angle of rotation of the blades of l-lfl which necessitates a backward movement of the blades by the amount surpassing 360 at the beginning of the winding-up of the shutter.

The variation of theelasticity of the act-uating spring 71 and of the duration of the opening-period is eflI'ected by rotating the milled head i Thereby one also-attains a variation of the elasticity of the spring Z so that to the amount of the force actuating the blades a, there always corresponds the amount of the force lessening the motion of the blades at the finish.

e claim:

1. Photographic shutter, comprising a plurality of shutter blades rotatably disposed, these blades having the shape of spherical bowls a spring for actuating the shutter blades, means for winding up this spring, coupling means adapted to impart tothe shutter blades, on the said spring'being wound up,

a rotation through over 360, and means for releasing the spring.

2. Photographic shutter, comprising a plurality of shutter blades rotatably disposed, these blades having the shape of spherical bowls, a spring for actuating theshutter blades, and a second spring for checking the motion of the shutter blades. v

3. Photographic shutter, comprising a plurality ot' shutter blades rotatably disposed, these blades having the shape of spherical bo\\'ls,' a spring for actuating the shutter blades, :1 second spring for checking the mo-.

tion of the shutter blades, and means for simultaneously varying the elastlcity 0t both springs in the same sense.

WALTHER BAUERSFELD. FRANKLIN PFEIFFER.

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