Abstract: A non-flexible endoscope comprises a slender insert section which is capable of being inserted from a leading end thereof into cavities of living bodies, an objective lens system for forming a primary image within the insert section, and a relay lens system for transmitting said primary image so as to form a secondary image, wherein the insert section satisfies the following condition:0.3<D.sub.1 /D.sub.2 <0.7wherein the reference symbol D.sub.1 represents a distance as measured from a first surface of the objective lens system to the primary image and the reference symbol D.sub.2 designates a distance as measure from the first surface of the objective lens system to the secondary image.

Abstract: An objective lens system for endoscopes comprising, in order from the object side, a first lens unit having a negative refractive power, an aperture stop, a second lens unit having a positive refractive power and a third lens unit having a positive refractive power, and using an aspherical surface adopted as an image side surface of the second lens unit or an object side surface of the third lens unit. The objective lens system is of a nearly telecentric retrofocus type, composed of a small number of lens elements and compact.

Abstract: A connector cover structure employed as a connector for electrical wires in an automobile is made of a synthetic resin, has a substantially cylindrical form and has, on an inner wall thereof, abutting walls which make engagement with a proximal end portion of one connector member and abutting walls which make engagement with grooves provided at a proximal end portion of the other connector member. Thus, incomplete fitting of the connector members can be detected, the entire connector can be protected and a reliable electrical connection can be provided.

Abstract: An eyepiece lens system for endoscopes comprising a plurality of lens components and using at least one aspherical surface. This eyepiece lens system is composed of a small number of lens elements and has favorably corrected aberrations.

Abstract: An objective optical system for endoscopes consisting, in the order from the object side, of a front lens unit having negative refractive power, an aperture stop and a rear lens unit having positive refractive power and comprising at least one aspherical surface in each of said lens units. This objective optical system for endoscopes has distortion of a small absolute value, a distortion curve of natural shapes, favorably corrected aberrations, and is composed of lens elements easily manufacturable.

Abstract: In order to enable to sufficiently deflect the viewing direction for a distal end having an end surface substantially perpendicular to the optical axis of an objective optical system and minimize aberrations produced due to the deflecting action, the objective optical system for endoscopes comprises at least one surface designed as a deflecting surface or an eccentric surface on the image side of the surface nearest the object to be observed out of the surfaces of the optical components composing the objective optical system so that the light is refracted at least twice for deflecting the viewing direction.

Abstract: A nearly telecentric objective lens system for endoscopes comprising an aperture stop, and a lens unit which has a positive refractive power and is arranged after said aperture stop, wherein said aperture stop is located at the front focal point of said positive lens unit and a single aspherical surface or a plurality of aspherical surfaces are arranged only in said positive lens unit. Distortion is corrected favorably in the objective lens system for endoscopes.

Abstract: An objective optical system for endoscopes consisting, in the order from the object side, of a front lens unit having negative refractive power, an aperture stop and a rear lens unit having positive refractive power and comprising at least one aspherical surface in each of the lens units. This objective optical system for endoscopes has distortion of a small absolute value, a distortion curve of natural shape, favorably corrected aberrations, and is composed of lens elements easily manufacturable.

Abstract: An objective lens system includes, in order from the object side, a first lens component whose image side surface has a positive power and a second lens component whose image side surface has a positive power, said objective lens system having a wide field angle and sufficiently small inclination angles of the principal ray at all image heights.

Abstract: An objective lens system comprising, in the order from the object side, a first lens group having negative refractive power and a second lens group having positive refractive power, and so adapted as to perform variation of focal length and focusing by shifting the second lens group, with the first lens group kept fixed, in such a manner that magnification of the second lens group satisfies a certain definite condition.

Abstract: An illumination optical system for an endoscope comprising a light source, and a lens system arranged on the object side of said light source and having at least one aspherical surface, said illumination optical system being so designed as to satisfy the following conditions (1) through (3):(1) Height of ray h satisfying d/dh {sin A(h)}<0 exists within a range of 0.ltoreq.h.ltoreq.r.(2) A relation of sin A(h.sub.o).gtoreq.0.3 establishes for a certain value h.sub.o of h within a range of 0<h.sub.o <r satisfying d/dh {sin A(H.sub.o)}=0(3) S<0.5 S.sub.oThis illumination optical system has a wide illumination range and provides favorable light distribution at marginal portion with little loss of light quantity.

Abstract: In order to enable to sufficiently deflect the viewing direction for a distal end having an end surface substantially perpendicular to the optical axis of an objective optical system and minimize aberrations produced due to the deflecting action, the objective optical system for endoscopes comprises at least one surface designed as a deflecting surface or an eccentric surface on the image side of the surface nearest the object to be observed out of the surfaces of the optical components composing the objective optical system so that the light is refracted at least twice for deflecting the viewing direction.

Abstract: Tongue-and-groove pliers comprises a pair of plier members each having a jaw portion, a joint portion and a handle portion, a pivotal bolt, a nut, a spring member and a pressure transmitting member. The joint portion of one of the pair of plier members has a bolt hole, an annular groove including a through hole, and an arcuate protuberance. The joint portion of the other plier member has an oblong slot and a plurality of arcuate adjustable channels with which the arcuate protuberance is engaged. The spring member has a gap, a long downward projection and a short downward projection and is accommodated within the annular groove about the bolt hole. The pressure transmitting member has an insertion hole for the pivotal bolt and an engaging hole for the long downward projection of the spring member and is loosely fitted movably in the oblong slot of the other plier member.

Abstract: A device for protecting audio equipment adapted to be installed in an automobile against theft includes a code storage section for previously storing a specific code in a memory, a code entry section for entering a code when the audio equipment is to be operated, a comparator circuit for comparing the code entered from the code entry section with the code read from the memory, and a muting circuit that usually mutes the electrical signal which would otherwise be applied to the power amplifier of the audio equipment. Unless the specific code is entered from the code entry section, the audio equipment is made inoperative by the electronic lock.

Abstract: Slip-joint pliers have a pair of plier members each having a jaw portion and a handle portion, a pivotal bolt, a nut, and a spring member. The spring member is arcuate and has long and short downward projections. One of the plier members has a bolt whole and an annular groove including a through hole for accommodating the spring member therein. The other plier member has a bolt hole defined by first and second slip changeover holes communicating with each other and an engaging recess contiguously communicating with the first slip changeover hole. The short downward projection of the spring member abuts the wall surface of the through hole and the long downward projection contacts the wall surface of either the first slip changeover hole or the engaging recess to automatically bias open the jaw portions of the pair of plier members.