37results about How to "Appropriate length" patented technology

A zoom lens for a projection display device includes, in order from the enlarging side, a first lens group having negative refractive power and that is stationary during zooming, second and third lens groups having positive refractive power, a fourth lens group that has refractive power that is much weaker in absolute value than the refractive powers of the other lens groups, and a fifth lens group having positive refractive power and that is stationary during zooming. The second, third, and fourth lens groups move with coordinated movements continuously toward the enlarging side during zooming from the wide-angle end to the telephoto end of the zoom range. The zoom lens satisfies certain conditions related to focal lengths of the zoom lens and lens groups and distances along the optical axis. A projection display device uses the zoom lens.

A rotary furnace hearth wherein a hearth carriage carrying a hearth comprises a plurality of hearth carriages respectively having propulsion systems, wherein adjoining hearth carriages are coupled by coupling bolts and nuts via spacers interspaced in a single row in a horizontal plane, whereby even if the hearth carriages deform due to heat at the time of operation, they are structured to be able to freely deform without mutual constraint in the event of curved deformation, so the hearth carriages are maintained in individually stable states at all times.

Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22<cf / f12<1 is satisfied, where f12 is a composite focal length of the first lens-group RG1 and the second lens-group RG2, and cf is a focal length of the rear converter lens RCL.

The invention relates to the field of spinning thread traction, in particular to a spinning thread traction device. The spinning thread traction device comprises a rack and further comprises an unreeling wheel and a reeling wheel which are rotationally connected with the rack. A disc is arranged between the unreeling wheel and the reeling wheel and fixedly connected with a sliding piece which is vertically in sliding connection with the rack. A drive piece fixed to the rack is arranged below the sliding piece, and an output shaft of the drive piece is coaxially connected with a cam abutting against the bottom of the sliding piece. A crank and rocker mechanism capable of driving the reeling wheel to rotate is hinged to the sliding piece, a reeling shaft of the reeling wheel is rotationallyconnected with the rack, and a one-way bearing is arranged at the connecting position. The scheme is adopted for spinning thread traction, and spinning thread fracture can be avoided.

The invention discloses a device for hoisting an equipment mounting frame. The device comprises a cross beam, wherein a lifting appliance arm is welded at one end of the cross beam, an inverted V shaped curved surface is formed on the upper top surface of the cross beam, a hook I is connected with the highest point of the inverted V shaped curved surface of the cross beam, the lifting appliance arm is of an I shaped structure formed by two long beams and one short beam, a plurality of connecting holes are formed in the short beam, a plurality of abrasion-proof rods are horizontally fixed on the short beam and are located just under the connecting holes in one-to-one correspondance, a hoisting rope passes through any one connecting hole in the short beam and the underside of the hoisting rope is connected with a hook II, the hook II is fixedly connected with a hanger, and the hanger is in bolt connection with the mounting frame. The device can ensure the levelness and the perpendicularity of the mounting frame unchanged in a hoisting process; the cross beam is of a stable triangle structure, a lightening hole can eliminate partial stress, the four corners of the mounting frame are perpendicularly hoisted by virtue of the length of the cross beam, and the length of the hoisting rope is appropriate, so that the stability and the balance of the whole mounting frame are ensured, and the design requirements on the levelness and the perpendicularity of a machine are met.

The invention relates to a frame for moving a tower. Wheels are arranged at the bottom of the frame. The frame is characterized in that a main support leg oil cylinder is arranged at the bottom of the frame; when the main support leg oil cylinder is propped up, the wheels leave from the ground; two girders are arranged on two sides of the frame; each girder is hinged, supported and connected witha frame auxiliary supporting leg by an auxiliary supporting leg pin roll; an auxiliary supporting leg oil cylinder is arranged on the frame auxiliary supporting leg; and a frame connecting and fixingplate for fixing the frame auxiliary supporting legs is welded on the frame. The invention has ingenious, compact and reasonable structure and can realize the integral movement of the tower; equipment on the tower is free from being detached and the mutual positions during original work can be maintained in the process of moving; rotatably-foldable frame auxiliary supporting legs are arranged on the frame and can ensure that the gravity center of the tower is stable during turning over; and after the frame auxiliary supporting legs are folded, the length of the frame is proper and the frame is convenient for integral moving, moving and transiting.