Some embodiments provide a belt tensioning mechanism for a 3D printer and a 3D printer. In those embodiments, the belt tensioning mechanism comprises a base, a driving pulley, at least one timing pulley, a sliding block, a tensioning pulley, a spring. The base is provided with a first sliding groove. The driving pulley and the at least one timing pulley are mounted on the base and are connected in series with each other via a belt. The sliding block is mounted on the base and is capable of sliding along the first sliding groove. The tensioning pulley is mounted on the sliding block and is connected in series with the driving pulley and the at least one timing pulley via the belt so as to tension the belt. The spring is configured to apply an elastic force to the sliding block.

Various embodiments provide a timing belt tensioner for a 3D printer and the 3D printer. In those embodiments, the timing belt tensioner includes: a mounting frame, an idler and an elastic member, where the idler is connected to the mounting frame, and a timing belt of the 3D printer is wound around the idler, and is configured to drive a movement mechanism of the 3D printer to move on an XY plane; and the elastic member is configured to connect the mounting frame and a base of the 3D printer such that the mounting frame drives the idler to slide to a balance position relative to the base under an elastic force of the elastic member. When at the balance position, a balance is reached between the elastic force of the elastic member and a tensile force of the timing belt acting on the idler.

A hydraulic tensioning device for a chain drive, having a tensioning piston which is guided in a holder and which, on its outer circumferential surface, has locking grooves, an inner guide which projects into a cavity of the piston, and a locking element which has at least two annular sections and at least two radial extensions, wherein the locking element can be placed in engagement by the at least two annular sections with one of the locking grooves, and having a clamping stop and a sliding stop which are axially spaced apart from one another. To simplify the structural design, the holder has at least two axial extensions which extend in an axial direction between the clamping stop plane and the sliding stop plane, wherein the at least two axial extensions and the tensioning piston do not enclose the at least two radial extensions.

In an embodiment, a tensioning apparatus includes a housing and a fastener extending at least partially through the housing. The apparatus also includes a trolley adjustably positioned within the housing about the fastener. The apparatus also includes a pulley disposed outside the housing and coupled to the trolley, where the pulley moves in unison with the trolley along an opening in the housing.

A tensioner with a bracket, a tensioner body coupled to the bracket for rotation about a first axis, a first and second wheels that are coupled to the tensioner body for rotation about second and third axes, respectively, that are parallel the first axis, and a spring that biases the second wheel along a line of action relative to the tensioner body. The second wheel is coupled to the tensioner body for movement between first and second positions along the line of action.

A snowblower belt drive system a tensioner pulley that can slide forwardly and rearwardly in a path that is substantially parallel to an endless drive belt between a drive pulley and a driven pulley. A drive belt engagement spring urges the tensioner pulley rearwardly along the slot to engage the drive pulley and driven pulley. A manual return spring urges the tensioner pulley forwardly along the slot to disengage the drive pulley and driven pulley.

To provide a tensioner capable of keeping, with a simple structure, oil pressure in an oil pressure chamber stable. The tensioner includes a pressure adjusting mechanism that adjusts oil pressure in the oil pressure chamber. The pressure adjusting mechanism includes a cylinder part, a piston unit set inside the cylinder part so as to be able to approach and separate from the oil pressure chamber, and piston biasing units that bias the piston unit toward the oil pressure chamber. A liquid tight seal condition is kept between the cylinder part and the piston unit at any position between a position where the piston unit has moved closest to the oil pressure chamber and a position where the piston unit has moved closest to the adjustment space. The piston biasing units include at least two piston springs.

A tensioner comprising a carrier pivotably mountable to a mounting surface, an arm having a first pulley journalled thereto and a second pulley journalled thereto, the arm slidingly engaged with the carrier for a linear movement with respect to a carrier axis A-A, and a spring disposed between the carrier and the arm, the spring resisting an arm movement along carrier axis A-A.

An automatic belt tensioner for a hybrid vehicle is disclosed. The automatic belt tensioner includes an arm body including an upper arm on which first and second idlers are mounted and a lower arm on which a third idler is mounted. The automatic belt tensioner further includes a spring provided between the upper arm and the lower arm and providing elastic force for relative longitudinal movement of the upper arm and the lower arm, and a rail bracket mounting the arm body on an engine and guiding relative longitudinal vertical motion of the arm body.

An actuator for transmitting an input force in a first direction from an input mechanism to a force in a second direction at an output mechanism. The actuator may be incorporated into a tensioner for tensioning a belt. The device includes a plurality of aligned spherical elements in a curved raceway. The input mechanism transmits force to a first of the series of spherical elements. The spherical elements are substantially incompressible so that the series of spherical elements transmits the force along the curved raceway from the input mechanism to the output mechanism.