Function-conversion device for ground monocular telescope

A function-conversion device for a ground monocular telescope of an erecting-prism type ground monocular telescope. The device includes a rotational plate so mounted as to be horizontally movable in a vicinity of the focal plane of the objective lens of the telescope, with a plurality of windows being provided in the rotational plate and with a reticle and/or a visibility diphragm or a second objective lens being mounted in alignment with the windows. This arrangement provides a convenient and easy-to-handle function-conversion device since the windows can be selectively moved into the vicinity of the focal plane.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a function-conversion device for the ground 
monocular telescope and more specifically to a convenient and 
easy-to-operate function-conversion device for a ground monocular 
telescope operating on the erecting-prism principle of wherein a reticle 
removal/mounting, a visibility diaphragm, magnification change or other 
functions are integrated. 
2. Description of the Prior Art 
Conventionally, the ground monocular telescopes operating on the 
erecting-prism principle have been in extensive use, due to their ease of 
handling, brightness sufficient for observation purposes, and other 
advantages. They have normally found their applications in the observation 
of wild birds, shooting matches and other purposes, because of their 
reduced weight and ease of operation. 
Such ground monocular telescopes operating on the erecting-prism principle 
have had difficulties in adjusting visibility and field of view in 
multiple stages, despite their peerless capabilities. 
For instance, as is well known, a reticle is mounted in order to determine 
the distance to a particular object. In the case of the telescope under 
consideration, it would be impossible to mount a reticle only when it was 
necessary, and thus it had to be in a mounted state at all times. This 
resulted in the obstruction by the scales of the reticle to the view of 
the observer except while a distance was being measured. 
These are shortcomings of an erecting-prism type ground monocular telescope 
which can result inevitably from its advantages. For this reason, in the 
conventional system, there was nothing which could be done for it but to 
make the visibility and field-of-view adjustment function exceedingly 
simple, because a reticle was not free to be mounted or removed, as well 
as the magnification adjustment could be done only in a single stage. 
Accordingly, an erecting-prism type ground telescope incorporating multiple 
visibility and field-of-view adjustment functions, has been strongly 
desired. 
With the above taken into account, the object of the present invention is 
to provide a convenient, and easy-to-handle function-conversion device for 
an erecting-prism type ground monocular telescope, which is designed to 
overcome the defects from which the conventional equipment has suffered, 
and to select appropriate levels of visibility and field-of-view. 
SUMMARY OF THE INVENTION 
In an erecting-prism type ground monocular telescope, a function-conversion 
device according to the present invention has a rotational plate so 
mounted as to be horizontally movable in the vicinity of the focal plane 
of an objective lens, with a plurality of windows being equipped with said 
rotational plate and with a reticle and/or a visibility diaphragm or a 
second objective lens being mounted onto said windows. 
This equipments makes it possible to use a reticle for the observation of a 
distance only when it is required, and also makes it easier to change 
magnifications.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the above drawings, 1 and 2 each represent a prism, 3 an objective lens, 
4 an ocular lens, 5 a rotational plate, 6 the center of rotation (rotation 
axis), 7 and 8 each designate a window, 9 a reticle, 10 a visibility 
diaphragm, 11 a turning ring, 12 a pin, 13 a rotational plate, 14 and 15 
each designate a window, 16 a second objective lens, 17 a cover, 18 a 
turning ring, 19 a notch and 20 a notch. 
Referring now in detail to the drawings, FIG. 1 shows the principle of the 
function-conversion device according to the preset invention. As indicated 
in FIG. 1, in an optical system comprising prisms 1 and 2, an objective 
lens 3 and an ocular lens 4, a rotational plate 5 capable of moving 
horizontally towards and away from the objective lens 3 is provided in the 
vicinity of the focal point (F) of the objective lens 3. The rotation axis 
or central point 6 of said rotational plate 5 is located at approximately 
one-half of the displacement of the rays of light emitting from said 
optical system(A). 
The rotational plate 5 has windows 7 and 8 as in the case of FIG. 1. Said 
rotational plate 5 exhibits the cross section along I--I in FIG. 2. The 
window 7 is equipped with a reticle 9, and the window 8 with a visibility 
diaphragm 10. 
Rotation of the rotational plate 5 can be accomplished by, for instance, 
causing a rotary ring (turning ring) 11 equipped with a pin 12 to rotate. 
FIG. 3 shows an embodiment wherein a second objective lens 16 is provided 
so as to be aligned with either of the windows 14 and 15 of a rotational 
plate 13. In this case, the adjustment for the focal point (F) can be 
readily accomplished by means of a sliding mechanism of the ocular lens 4 
and/or objective lens 3 such as by moving the ocular lens 4 toward and 
away from the plate 13. When said second objective lens 16 is adopted, a 
difference in focal point occurs, and accordingly, the rectilinear 
movement of said ocular lens 4 in the direction toward the said rotational 
plate 13 may be adjusted with a sliding mechanism such that the second 
objective lens 16 comes close to said ocular lens 4. 
This arrangement permits adjustment of the difference in focal point. 
The construction of a means which enables the rotational plate 5 to rotate 
as show in FIG. 1 is illustrated in FIG. 3, which is only one example of 
such an arrangement. 
The rotational plate 5 turns around the central point 6. An ocular lens 
system 4 has a turning ring 18 mounted rotatably on a cover 17 so as to 
rotate above a turning axis. Said turning ring 18 has a pin 12, said pin 
12 being inserted into semi-annular notch 19 in said cover, and also into 
a radially extending notch 20 in said rotational plate 5. 
FIG. 5 shows said rotational plate 5 in the present embodiment. 
In this example, the window 8 equipped with a visibility diaphragm 10 is 
mounted in the light path opposed to the prism. A pin 12 is provided with 
a turning ring 18, and the pin 12 is caused to move along the notch 20 of 
the rotational plate 5 in synchronization with the rotation of said 
turning ring 18 around the turning axis which is coincident with a central 
point(B). 
To locate a window 7 on which a reticle 9 is mounted at the central point, 
said turning ring 18 is caused to rotate such that the pin 12 is moved 
through an angular displacement of about 90.degree. about the turning axis 
B (angle .alpha.) and the pin 20 is located the left side of FIG. 5. The 
window 7 is thus rotated about 150.degree. about the rotation axis 6 
(Angle .beta.). 
It is, of course to be understood that the form of my invention herein 
shown and described is to be taken as a preferred example of the same and 
that various changes in the shape, size and arrangement of parts may be 
resorted to. 
The conversion equipment of the present invention makes it is possible to 
integrate a reticle, a visibility diaphragm, magnification change and 
other functions, serving to improve the utility of an erecting-prism 
system as a ground monocular telescoping and achieve a multi-function and 
easy to handle telescope.