Pentax Corporation

Maiko Takashima

Hiroshi Nomura

Takamitsu Sasaki

Kazunori Ishizuka

A gear mechanism includes a driving gear, a driven gear, and an idler gear which is in mesh with the driving gear and the driven gear, wherein rotation of the driving gear is transferred to the driven gear via the idler gear. The idler gear includes first and second spur gears which are positioned adjacent to each other in an axial direction and are generally centered about a common axis, radial teeth of the first and second spur gears each being the same in shape, pitch and the number of teeth, and the first and second spur gears being biased to rotate in opposite directions. The first and second spur gears are connected so as to be relatively movable in a radial direction normal to the axial direction while maintaining the first and second spur gears in mesh with the driving gear and the driven gear.

Gear mechanism with an idler gear, a gear mechanism with a device for eliminating backlash between gears, and a motor driving mechanism

A lens barrel includes a lens frame for supporting a photographing lens group, the lens frame including a guide bore which extends in a direction parallel to the optical axis; a support barrel, wherein the lens frame can be inserted into and removed from a front opening of the support barrel; a rod receiving portion formed inside the support barrel; a bracket detachably attached to a front end of the support barrel; and a guide rod provided on the bracket for guiding the lens frame to move relative to the support barrel in the optical axis direction, the guide rod engaging with the rod receiving portion when the bracket is attached to the support barrel. The lens group frame can be taken out of the support barrel through the front opening when the bracket having the guide rods is removed from the support barrel.

Lens barrel

An eccentricity-prevention mechanism includes a pair of lens-supporting rings for supporting a pair of lens groups, respectively; and a pair of positioning recesses and a follower projection formed on one and the other of opposed surfaces of the pair of lens-supporting rings, such that the follower projection engages with one of the pair of positioning recess to define a relative position of the pair of lens-supporting rings with respect to the optical axis, at a mutually close position and at a mutually distant position. At least three pairs of the positioning recesses and at least three follower projections are provided at different positions in a circumferential direction, so that eccentricity between the pair of lens-supporting rings is eliminated when all of the follower projections are concurrently brought into engagement with corresponding positioning recesses.

Eccentricity-prevention mechanism for a pair of lens-supporting rings

A camera includes a lens support frame which supports a photographing lens group; an outer lens barrel which is provided on the front end thereof with a photographing aperture through which the lens support frame is moved; a lens barrier mechanism which opens and closes the photographing aperture of the outer lens barrel; a lens drive mechanism which moves the lens support frame in the outer lens barrel between a forward movement extremity in which the front end of the lens support frame is located in front of the photographing opening in an optical axis direction, and a rearward movement extremity in which the front end of the lens support frame is located behind the photographing aperture; and a barrier detection device for detecting the opening state of the lens barrier mechanism, based on an amount of movement of the lens support frame in the optical axis direction via the lens drive mechanism.

Camera having lens barrier

A zoom lens barrel assembly includes a first lens group including first and second sub-lens groups; a second lens group; a sub-lens group switching mechanism for moving the first or second sub-lens group away from the other in a short focal length photographing range, and toward the other in a long focal length photographing range; and a zoom cam mechanism having front and rear lens group cam grooves. The rear lens group cam groove includes first and second portions corresponding to the short and long focal length photographing ranges, respectively, the first and the second portions connected to each other via a discontinuous portion. The front lens group cam groove includes a non-linear portion which corresponds to the short focal length photographing range and provides a non-linear path, and a linear portion which corresponds to the long focal length photographing range and provides a linear path.

Zoom lens barrel assembly

A lens barrel includes front and rear sub-lens groups; front and rear sub-lens group frames for supporting the front and rear sub-lens groups, respectively; a lens frame shift mechanism for causing the front sub-lens group frame and the rear sub-lens group frame to move relative to each other to obtain the mutually close position and the mutually distant position; a first lens group positioning surface provided on the front sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a rear surface of the front sub-lens group; and a second lens group positioning surface provided on the rear sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a front surface of the rear sub-lens group.

A light intercepting member driving mechanism includes light intercepting members which are each rotatable about a rotational axis parallel with an optical axis to open and close a photographing aperture; a drive ring which engages with the light intercepting member to open and close the light intercepting member in accordance with the angular displacement of the drive ring in forward and reverse directions about a rotational axis coincident with the optical axis; a motor which rotates the drive ring in the forward and reverse directions; a position indication portion provided on the drive ring to indicate the angular position of the drive ring; and a stationary detector which detects a passing of the position indication portion when the drive ring is rotated. The opening state of the light intercepting members is detected by the stationary detector and the position indication portion.

Light intercepting member driving mechanism

A reduction gear mechanism includes at least first and second axes which extend parallel to each other; one of the first and second axes rotatably supports at least two gears arranged one after the other in the axial direction thereof, and the other of the first and second axes rotatably supports at least one gear, and the gears provided on the first and second axes being engaged with each other in such a manner that the gear supported on one of the first and second axes successively and alternatively engages with the gear supported on the other of the first and second axes.

Reduction gear mechanism

A lens drive mechanism includes first and second sub-lens group frames for supporting first and second sub-lens groups; a support frame for supporting the first and second sub-lens group frames; a first linear guide mechanism which linearly guides the first sub-lens group frame and prevents rotation thereof; a second linear guide mechanism which linearly guides the second sub-lens group frame, while limiting rotation thereof, at two extremities of rotation thereof; a lens frame shift mechanism for causing the first and second sub-lens group frames to move to the mutually close or distant position; and a linear displacement mechanism which integrally moves the first and second sub-lens group frames in the optical axis direction, in the mutually close or distant position. A linear guide clearance of the first linear guide mechanism is larger than a linear guide clearance of the second linear guide mechanism.

Lens drive mechanism

A lens shutter mechanism includes a support frame having a photographing aperture; at least three shutter sectors which open and close the photographing aperture via rotating axes which extend parallel to the optical axis; and at least three diaphragm sectors which vary an aperture diameter formed by the diaphragm sectors to restrict the diameter of the photographing aperture, independently from the shutter sectors, via rotating axes which extend parallel to the optical axis. The support frame is provided with rotational center portions spaced from each other at equi-angular intervals about the optical axis, the number of the rotational center portions being same as each of the number of the shutter sectors and the number of the diaphragm sectors. Each of the rotational center portions rotatably and coaxially supports a one of the shutter sectors and one of the diaphragm sectors.

Lens shutter mechanism

A lens assembly includes an exposure control unit having an exposure control member; a lens drive unit including a lens drive mechanism which moves a photographing lens group in an optical axis direction; center apertures which are formed in the exposure control unit and the lens drive unit, respectively, at the center portions thereof, which define a lens movement opening when the exposure control unit and the lens drive unit are connected to each other; and a lens support frame which supports the photographing lens group, the lens support frame being provided in the lens movement openings so as to move in the optical axis direction and driven via the lens drive mechanism.

Lens assembly

A stopper structure for use in a lens barrel assembly, the lens barrel assembly having a helicoid ring which includes a male helicoid, on the outer periphery of the helicoid ring, for engaging with a female helicoid on an inner periphery of a fixed barrel secured to a camera body; and gear teeth formed along the male helicoids to extend between the male helicoids and arranged in a circumferential direction about an optical axis, the helicoid ring moving along the optical axis while been driven by a pinion which is engaged with the gear teeth; wherein the stopper structure includes a stopper member which engages with at least one tooth of the gear teeth in order to prevent rotation of the helicoid ring.

Stopper structure for lens barrel assembly

A lens barrel having a zoom lens system including a plurality of variable power lens groups which includes a switching lens group having two sub-lens groups which are optically operable in mutually close and distant positions, the lens barrel includes a first sub-lens group frame for supporting one sub-lens group; a second sub-lens group frame for supporting the other sub-lens group; a switching lens group frame for supporting the first and second sub-lens group frames; a shift mechanism for selectively moving the first and second sub-lens group frames in the switching lens group frame to the mutually close and distant positions; and a switching lens group frame moving mechanism for moving the switching lens group frame with the other variable power lens group(s) along a predetermined path to vary the focal length; wherein combined movement of the shift mechanism and the switching lens group frame moving mechanism provides a zoom path for the sub-lens groups.

Zoom lens barrel

A lens guide mechanism includes a lens frame which supports a photographing lens group, the lens frame including a plurality of guide holes extending in a direction parallel with an optical axis; a support barrel in which the lens frame is provided; a gear holding member which is provided at a front end of the support barrel; a gear train which is held between the support barrel and the gear holding member, the gear train constituting a drive mechanism for the lens frame; and a plurality of linear movement guide rods provided in the gear holding member, which extend through the guide holes of the lens frame and support the lens frame to move linearly in the optical axis direction relative to the support barrel.

Lens guide mechanism

A lens shutter mechanism includes, between front and rear support frames having photographing apertures, shutter sectors which open and close the photographing apertures; a shutter drive ring which is rotatable about the optical axis to drive the shutter sectors; diaphragm sectors which change an aperture diameter of the photographing apertures independently of the shutter sectors; and a diaphragm drive ring which is rotatable about the optical axis to drive the diaphragm sectors. The shutter drive ring and the diaphragm drive ring are located at different radial positions and at the same optical axis position. One and the other of the shutter drive ring and the diaphragm drive ring is provided with an inner flange and an outer flange respectively, which radically project toward each other so as to overlap in the axial direction, and engage so as to be relatively slidable in the circumferential direction.

Growing community of inventors

Tokyo, Japan

Maiko Takashima