SU656553A3 - Variable objective with variable focal length mechanism - Google Patents

Description

HOBjieiiFihie groups. Chins 11 - 14. Lens groups 11 and 2 are located in mandrel 1, and lenses 13-14 are in frame 2, the lens contains a diaphragm assembly of plates 15, rotating ring 16 and housing 17 installed between fixed groups of lenses 8 and 9.

Through the gear pair 18-19, the rotation from the drive (not shown) is transmitted to the drive shaft on which the gear wheel 20 is mounted. From the gear wheels 19 and 20 mounted on the drive shaft 21, the wheels 1 and 2 rotate through their gear rims 22 and 23, in which the groups of lenses 11, 12 and 13, 14 are intermixed, interacting with curvilinear guides 3, 4 and 5, 6 with their pins.

An additional adjustment of the diaphragm (manual reversal of the ring 16) is superimposed further, which depends on the focal length and is achieved by reversing the diaphragm body 17, which is equipped with a gear rim 24 rotating through the gear pair 25-26 from the drive shaft 21.

A variant of communication of one of the movable frames with a drive shaft, performing alternate rotation of each, includes (Fig. 2) a differential gear from a gear wheel 27, meshing with a gear wheel 18 of a drive, a cross-shaped shaft 28 and a gear wheel 29.

The cross-shaped shaft 28 is rigidly connected to the drive shaft 21, so that when it is stationary, the rotation from the drive is transmitted from the wheel 27 to the wheel 29 and from it to the rotation of the frame 1 through its toothed crown 22. The frame 2 does not rotate. When the gear wheel 29 is locked, the rotation from the wheel 27 rotated from the drive is transmitted to the cross-shaped shaft 28, the drive shaft 21 and the gear wheel 20, which rotates the frame 2 through its gear ring 23.

The locking of the frames during their stop is made in the form of one-arm levers 30 and 31, mounted on the axis 32, with rollers 33 and 34 at the ends. The rollers 33 and 34 sink into the notches on the annular projections 35 and 36 of the frames 1 and 2. The initial or final positions of the frames 1 and 2 are determined by the stops 37, 38.

In the described zoom lens (thirty-fold), a smooth, stepless adjustment of the range of focal lengths was carried out due to a single drive and simultaneous movement of the diaphragm from the latter with the installation of the required relative aperture of the zoom lens.

Claims (2)

1. A lens with a mechanism for changing the focal distance, containing fixed and placed between them (at least two) moving groups of lenses mounted in a frame with the ability to move in it according to a certain law due to curvilinear guides on the frame, characterized in that the purpose of providing a smooth change in the focal length of a zoom lens for a range of focal lengths F 20 -600 mm and relative apertures 1: 1.7, 1: 2.1, introduced a second frame with a pair of moving groups of lenses associated with the first one one shaft, the curvilinear guides on both frames are made with lowering slopes corresponding to the end and the beginning of the range of focal lengths, and between the frames there are concentrically two fixed groups of lenses, between which there is a diaphragm assembly with plates, a rotating ring which engage with a gear pair mounted on the drive shaft. 2. The zoom lens according to claim 1, characterized in that one of the movable frames is connected to the drive shaft through a differential mechanism with the possibility of alternating rotation of each frame, provided with a lock in the form of a single arm mounted on the axis with a roller at the end, which interacts with a ring ledge on a frame. Sources of information taken into account in the examination 1. US patent No. 3610733, cl. 350-186, G 02 B 7/04, 1971.