A multi jack tensioner for applying tension to a fastener, the tensioner comprising: a body having at least one section, including a first body section formed to engage an elongate fastening member or integrally formed therewith; a load bearing member for applying force to a workpiece to be fastened and arranged for location about said fastening member adjacent the body; a plurality of pressure chambers between the load bearing member and the body arranged to displace the at least one body section axially relative to the load bearing member in response to hydraulic pressure; and a plurality of jack bolts extending between the body section and the load bearing member for further displacing the first body section from the load bearing member; wherein application of hydraulic pressure to one or more of the plurality of pressure chambers displaces the first body section from the load bearing member thereby tensioning said fastening member and whereby subsequent tensioning of the fastening member is applied by operation of the jack bolts.

A method for preloading a bearing includes releasably, threadably, and directly attaching an attaching member to a circumferential outside surface of an exposed end of a threaded shaft of an axle or spindle. A frame is axially separated from, and coupled to, the attaching member. A plurality of extensions extends from the frame axially past the attaching member toward the wheel hub assembly. An adjustment mechanism moves the frame and the plurality of extensions axially towards the wheel hub assembly to contact the wheel hub assembly and/or the bearing to apply a preload to the bearing within the wheel hub assembly.

The present invention refers to a device for tensioning a connecting element fastened to a component to be tightened, which comprises an engagement element having an engagement section receiving and holding the connecting element, a support element configured to support the device against the component, and an actuating unit having a fluid chamber for receiving a fluid, wherein the actuating unit is configured to manipulate a volume of the fluid chamber so as to move the engagement element relative to the support element. The device further comprises a vent opening fluid-communicatively connectable to the fluid chamber which is disposed in the region of the engagement section.

A pretensioning element pressure screw (11) having a shank (12) which has a first end (13) and a second end (14), opposite the first end (13). Starting from the first end (13), a threaded portion (16), having an outer diameter (D), is formed adjacent a threadless shank portion (21), having an outer diameter (dg). The threadless shank portion (21) extends to the second end (14) of the shank (12). An engagement mechanism (26) for a tool is arranged at the first end (13) of the shank (12). The outer diameter (dg) of the threadless shank portion (21) corresponds to 1.0 times the outer diameter (D) of the threaded portion (16). A pretensioning element and a pretensioning screw body element having a plurality of such pretensioning element pressure screws (11) is also disclosed.

An expansion bolt comprises a bolt having an end-face anchoring means for the tension-resistant anchoring of the bolt on or in a first assembly part, which bolt has a truncated-cone-shaped cone section and a bolt threaded section in its end section opposite to the anchoring means with a nut screwed thereon, an expansion sleeve having a cylindrical lateral surface and an inner cone contour interacting with the cone section of the bolt, and a clamping device supported on a second assembly part for widening the expansion sleeve and applying an axial clamping force to the assembly parts to be connected together. The cone section of the bolt is tapered in the direction toward its anchoring means and the inner cone contour of the expansion sleeve is tapered in the same direction. The expansion sleeve bears a clamping flange protruding outward in the radial direction on its end opposite to the inner cone contour. The clamping device comprises a clamping ring having an axial passage opening. The expansion sleeve engages through this passage opening, permitting an adjustability of the expansion sleeve in relation to the clamping ring in the axial direction, and protrudes with its clamping flange beyond a peripheral region of the clamping device enclosing the passage opening. The clamping ring also comprises multiple pressure bolts arranged circumferentially distributed, which mesh with their thread in internally threaded holes extending through the clamping ring in the axial direction and act with their bases indirectly or directly against the second assembly part to widen the expansion sleeve and apply an axial clamping force to the assembly parts. Furthermore, a connection assembly having such an expansion bolt is described.

A multi jack tensioner for applying tension to a fastener, the tensioner comprising: a body having at least one section, including a first body section formed to engage an elongate fastening member or integrally formed therewith; a load bearing member for applying force to a workpiece to be fastened and arranged for location about said fastening member adjacent the body; a plurality of pressure chambers between the load bearing member and the body arranged to displace the at least one body section axially relative to the load bearing member in response to hydraulic pressure; and a plurality of jack bolts extending between the body section and the load bearing member for further displacing the first body section from the load bearing member; wherein application of hydraulic pressure to one or more of the plurality of pressure chambers displaces the first body section from the load bearing member thereby tensioning said fastening member and whereby subsequent tensioning of the fastening member is applied by operation of the jack bolts.

A hold down system for a building wall comprises a first rigid member and a second rigid member, the second rigid member being vertically spaced apart from the first rigid member, the first rigid member is supported on a horizontal member of a stud wall, the first and second rigid members including first and second openings, respectively; a tie-rod with a lower end portion for being anchored to an anchorage, the tie-rod extending transversely through the first and second openings, the tie-rod dividing the first and second rigid members into a first lateral section on one side of the tie-rod and a second lateral section on a diametrically opposite side of the tie-rod; first support and second support disposed between the first and second rigid members, the first support being disposed in the first lateral section, the second support being disposed in the second lateral section, the tie-rod extending through the first and second rigid members outside of the first support or the second support; and a nut threaded to the tie-rod, the nut exerting pressure on the second rigid member to place the tie rod under tension loading, the tension loading is transferred by the second rigid member to the first and second supports to subject the first and second supports to compression loading, thereby causing the first rigid member to press on the horizontal member of the stud wall via the first and second lateral sections of the first rigid member, thus distributing the compression loading.

The invention relates to a device for preventing spills from inside mining mills, said device maintaining a seal around bolts used to secure mill liners, such that the bolt remains under tension within a range of several millimetres along the length between the head and the nut of the bolt, with the length covered by the elements compressed between the head of the bolt and the device for preventing pulp leaks in mills, exerting pressure on the washer that provides a seal against leaks from inside the mill. The device comprises one or more pairs of Belleville washers which include an annular space into which a sleeve with an inner seal is inserted. Said sleeve includes a flange of larger diameter to allow the action of the bolt on the Belleville washers, said Belleville washers exerting pressure on the washer that provides a seal against leaks from inside the mill. The length of the sleeve is greater than or equal to the total thickness of the Belleville washers at maximum compression, and the flange of the sleeve is only required if the diameter inscribed on the contact surface with the bolt is smaller than the annular diameter of the Belleville washers.

A high-pressure sealing ring for hydraulic assemblies has a substantiallyL-shaped body with a leg and foot, where an external heel-portion is designed to provide a rolling line of sealing contact with the seat in the cylinder or piston in which it is seated.

A method and apparatus for pre-tensioning a bolt that joins two parts, each end of the bolt being threaded into a respective cavity of the two parts. According to one embodiment, the bolt including a double wedge pre-tensioning element, a washer disposed at each side of the double wedge and clamping elements fastening the wedges once the desired preloading has been attained. The bolt is pre-tensioned with a tensioning tool which acts on the pre-tensioning element, reducing a distance between the wedges while increasing the distance between the two parts to be joined and reducing a distance between the outer facing surfaces of the wedges and washers. The control system measures at least one of the distances described, with the tensioning tool acting in accordance with the measured distance.