2434 results about "Four-bar linkage" patented technology

The invention provides a fracturing blender truck. The fracturing blender truck comprises a chassis, a sand blending device, a four-connecting-rod mechanism and a power system. The sand blending device is arranged above the chassis and provided with a sand blender, and a closed-type mixing pump serves as the sand blender. The four-connecting-rod mechanism is capable of driving the sand blending device to move to enable a base of the closed-type mixing pump to contact with the ground, a first connecting rod and a third connecting rod of the four-connecting-rod mechanism are arranged on the chassis rotatably, and the sand blending device is arranged on a second connecting rod of the four-connecting-rod mechanism. The power system arranged on the chassis is connected with the first connecting rod and drives the four-connecting-rod mechanism to rotate to enable the closed-type mixing pump to contact with the ground. The fracturing blender truck has the advantages that the closed-type mixing pump serves as the sand blender, and the second connecting rod of the four-connecting-rod mechanism is used for bearing the sand blending device to enable the base of the closed-type mixing pump to be capable of contacting with the ground, so that the height of the closed-type mixing pump is decreased, suction capacity of the closed-type mixing pump is improved, a great quantity of fracturing fluid can be guided out, delivery capacity of the fracturing blender truck is increased, and the requirements on large-scale fracturing operation can be met.

A chair of the tilting type which includes a base, a seat and back, with the base pivotally supporting the seat with two parallel links of a four-bar parallel linkage, with one of the links extending to support the back. The four-bar linkage is duplicated on each side of the chair by forming the two opposite parallel links or cranks from the upturned ends of the tubes which pass through the base in parallel but vertically offset fashion, the base thus forming the fixed bar of the linkage with its opposite bar or coupler being formed by the seat. A spring within the base is operative on one (of both) of the tubes to urge the chair to an upright position. The tubes are pivotally connected to the seat and one of the tubes extends and is fixedly connected to the back. As the back tilts, the four-bar mechanism is engaged and lifts the seat which thereby uses the occupant's weight to counteract the reclining.Also disclosed is an adjustable armrest that can readily raised, or lowered, and optionally rotated in a horizontal plane.A further aspect of the present disclosure is a headrest that is pushed into place when the chair is reclined and retracted when the chair returns to an upright position.

A synchrotilt chair includes a base, a back, a seat, and a pair of parallel links pivoted to a rear of the base and to a bottom of the back to form a four-bar linkage arrangement. A spring arrangement includes leaf springs that extend between each link and the base to bias the link and in turn the back and seat toward an upright position, with the back and seat pivoting with a synchronous motion upon recline of the back. The base, the back, the seat, and the links are shaped to receive identical chairs along a stacking direction to form a densely nested stacked arrangement for compact storage. The base has a distinctive horizontal U-shaped mid-frame structure defining a plurality of corners, and further having up legs and down legs extending upwardly and downwardly, respectively, from each of the corners, with the pair of links attached to the two rearmost ones of the up legs. The base (and also separately the back and the seat structures) are injection molded as single pieces from a reinforced polymeric material in a manner that provides a lightweight, yet surprisingly rigid and sturdy construction. Armrests are pivoted to the back and have a shape configured to allow nested stacking while also providing excellent comfort, durability, and style.

In a headrest (1) for a vehicle seat, having a carrier (5), at least one upper and lower linkage (11, 15) linked to the carrier (5), which can be pivoted around horizontal axles (7, 17), a impact element (13) linked to the linkages (11, 15) which forms at least one four-bar linkage (19) with the linkages (11, 15) and the carrier (5), and an energy storage device (25), the energy storage device (25) driving the four-bar linkage (19) in the event of a crash, so that the impact element (13) comes out forward from an original position into a crash position that is locked against a backward movement by a crash lock, the upper linkage (11) and the lower linkage (15) are unparallel with respect to one another.

A dynamic spinal stabilization linkage for use in stabilizing of the spine. The linkage connects adjacent vertebrae to provide load-sharing and stabilization while allowing natural kinematics. The linkage comprises three rigid bodies joined in series with 3-degree-of-freedom spherical joint between each body. The joints have range-of-motion constraints which limit undesirable intervertebral motion.

An orthosis device generally includes two limb sections pivotably attached to each other in at least one degree of freedom and adapted for insertion of or attachment to adjacent portions of a limb of a user. Each limb section further includes a four-bar linkage and a spring member adapted to provide an equilibrium-inducing force corresponding to a combined weight of the limb section and the limb inserted therein or attached thereto. The equilibrium-inducing force allows every point in three-dimensional space to be a balanced position, such that a user with muscular abnormalities can move his or her limbs and hold them in place. A pivotable shoulder bracket for attaching the orthosis device to a wheelchair may also be provided. Furthermore, the orthosis device can be adapted to accommodate individuals of varying weight or with varying levels of disability by adjusting the spring member or providing powered actuators and force sensors.