DE1802897U - DEVICE ON IMAGERS FOR REMOTE CONTROL OF THE PROJECTION LENS - Google Patents

Description

Equipment on projectors for remote control of the projection lens.

The subject of the novelty relates to a device for refocusing of the lens for image sharpness.

Such devices on projectors are known. The one on the lens Acting adjustment stroke is preferably either a crank movement or a Stepping mechanism removed. The adjustment stroke becomes a rotatable around its axis If the crank is removed, the stroke movement is not uniform. He is known to succumb the sine function in terms of force and speed. With stepper mechanisms the adjustment stroke is not continuous, but jerky. When moving the lens for the purpose of setting the image sharpness, however, it must be as uniform as possible and continuous adjustability should be sought.

According to the innovation, as described in the drawing, for the adjustment stroke a spindle with screw thread (S) is proposed. This spindle drive is through a changeover gear optionally set in left or right rotation, whereby the longitudinally movable lens (0) is moved forward or backward from its position. The change gear, consisting of a bevel friction wheel (K), two plate-like disks (R1, R2) and longitudinally displaceable drive shaft (A) is designed as a friction clutch and is controlled by electromagnets, whose magnetic core is also the drive shaft (A) forms. The clutch has three switching positions: left-hand rotation, right-hand rotation and Rest position. The rest position is due to two mutually dependent on the axial displacement springs (F1, F2) acting on the drive shaft (A). Remain at rest the solenoid coils are separated from the circuit of the power source (B) by the switch (T). The changeover switch (T) is used to remotely control the changeover gear. It has three switch positions for forward, stop, reverse. In the lead position z. B. the coil (M1), in the return position the coil (M2) is connected to the circuit, so that the shaft (A) is drawn into either the magnetic field of the coil (M1) or coil (M2) and so the clutch is switched to the desired direction of rotation. The now right-or The left-hand spindle (S) makes the precise adjustment via the swivel arm (H) of the lens (0).

When the focus is achieved, the switch (T) is switched to "Halt". The lens remains in this setting until toggle switch (T) for another Refocusing is operated again.

So that the adjustment stroke for the lens in his, the focus corresponding width is limited, two switches (01, C2) are provided which trigger the changeover of the gearbox automatically at the turning points.

Claims (1)

Claims for protection Claim 1 device on projectors for remote control of the projection lens, in which the image sharpness is achieved by a motor-driven, Adjustment stroke acting on the object position is effected, characterized in that that the device has an optionally left or right-hand clutch, whose Drive shaft A is axially displaceable, is driven, one or several solenoids M 1 and M 2, the coupling of a threaded spindle S or other effect transmission means of the lens shift. Anbruch 2 device on image projectors for remote control of the projection objective according to claim 1, characterized in that the coupling consists of two plate-like disks R 1 and R 2 fastened on a shaft on the drive side and one on the output side There is friction wheel K and in the middle position the CD Drive disengages. - Claim 2 device on projectors for remote control of the projection lens according to claim 1 and 2, characterized in that the adjustment range of the stroke the lens is limited by one or more switching elements 01 and C 2, which are actuated by transmission links that are associated with the adjustment movement stand.