| 摘要 |
508,063. Navigation - teaching and optical apparatus. SOMMERVILLE, W. E. Dec. 21, 1937, No. 35312. [Class 114] [Also in Group XX] Navigation instruction apparatus comprises a projector adjustably mounted'on a stand and a curved screen concentric thereto and between them is a stand carrying a dummy compass card which a student operates following upon movements of the projector by the instructor. A projector 13 mounted on a base 12 has a bossing 11 fitting upon an upright peg 6 which is mounted for rotation on the upper part 2 of a stand 1. The spindle 6 is connected by two double reduction gears with an operating handle 20 whereby the projector can be moved slowly. For rapid movement, the bossing 11 is moved by hand on the spindle 6 with which it is normally in frictional engagement. The stand 1 has a number of platforms 3, 4, 5, and upon the platform 3 is disposed a circular tray 22 rotatable on a spindle 23 and having compartments in which slides representing navigation lights, sea marks and other navigation details are placed. The compartment over the tray is illuminated by light 47 and a compass 40 mounted on the top platform 2, illuminated by a screened light 45. A dimming resistance 48, 49 is provided for the projector. A compass card 29 is provided for the examinee and is free to revolve on the centre pin 30 in relation to a fixed indicator ring 32. A frame 33 carries a lubber line 34 to be positioned over the ring 32 and a wind indicator 35 and sight vane 36 are provided. The card and ring are transparent and illuminated by a light beneath them. The curved screen 50 is preferably made in segments carried by uprights 51, which have pins 54 engaging holes in brackets 55 upon the screen segments. In the twin side carrier, a combined key and shutter 57 is carried by the vertical frame bar of the carrier. The shutter works on a pin 58 fixed in the bar 59 and is normally held by a rubber spring 60. For releasing the shutter, a second spring 62 is provided, and when pulled downward slowly, may be used to unmask openings 71 in the slides to represent revolving or flare lights. The shutter may be drawn clear of the slide aperture by pressing down on the knob 61 and bringing the other end of the slot in the shutter up against the fixed pin 58. In order to increase the length of the arc swept, a second projector may be used, which is linked up so that a common indicator apparatus is used for both. In this case, the screen is in. the form of two arcs each concentric with its respective projector. |
