Abstract: A piston arrangement comprising a piston movable within a cylinder and having a stroke with a first end and a second end, wherein the piston is coupled to a crankshaft by a linkage mechanism including a toggle link which is pivotally coupled to the piston and pivotally coupled to a con-rod, wherein the toggle link has a first position corresponding to the first end of the piston stroke, a second position different to the first position also corresponding to the first end of the piston stroke, and an intermediate position between the first and second positions corresponding to the second end of the piston stroke such that the piston completes four strokes for every one revolution of the crankshaft.

Abstract: A piston arrangement comprising a piston movable within a cylinder and having a stroke with a first end and a second end, wherein the piston is coupled to a crankshaft by a linkage mechanism including a toggle link which is pivotally coupled to the piston and pivotally coupled to a con-rod, wherein the toggle link has a first position corresponding to the first end of the piston stroke, a second position different to the first position also corresponding to the first end of the piston stroke, and an intermediate position between the first and second positions corresponding to the second end of the piston stroke such that the piston completes four strokes for every one revolution of the crankshaft.

Abstract: A blind river and a method of assembly comprising a tubular shell and mandrel in combination. The mandrel comprises a stem and a radially-enlarged head which in use forms a blind head to the shell to set the rivet, in which either the head of the mandrel or the bore of the shell is formed with a plurality of depressions the bases of which lie on a notional circle having a diameter which, where the depressions are formed in the head of the mandrel, is less than the bore of the shell or, where the depressions are formed in the bore of the shell, is greater than the diameter of the head of the mandrel. The depressions, which are preferably generally longitudinally disposed, define ribs, ridges or other protusions therebetween which in use and on pulling the mandrel into the shell bore extend radially beyond the bore of the shell, so that material of the shell becomes displaced by contact with the ridges and occupies the depressions. The invention may be applied either to pull-through, or self-plugging rivets.

Abstract: A blind rivet and a method of assembly comprising a tubular shell and mandrel in combination. The mandrel comprises a stem and a radially-enlarged head which in use forms a blind head to the shell to set the rivet, in which either the head of the mandrel or the bore of the shell is formed with a plurality of depressions the bases of which lie on a notional circle having a diameter which, where the depressions are formed in the head of the mandrel, is less than the bore of the shell or, where the depressions are formed in the bore of the shell, is greater than the diameter of the head of the mandrel. The depressions, which are preferably generally longitudinally disposed, define ribs, ridges or other protrusions therebetween which in use and on pulling the mandrel into the shell bore extend radially beyond the bore of the shell, so that material of the shell becomes displaced by contact with the ridges and occupies the depressions. The invention may be applied either to pull-through, or self-plugging rivets.

Abstract: A self-plugging blind rivet comprises a tubular shell shank having a preformed radially enlarged head at one end a region of increased diameter and hardness at the tail end, adjacent the head of the stem. The rivet is formed by compressing the stem and a plain cylindrical shell in a die having a portion of enlarged bore diameter at the tail end region, whereby the shell is expanded into the enlarged bore portion with resulting work hardening.

Abstract: A breakstem rivet installation tool includes a jaw mechanism (12) for gripping the stem of a rivet, and a pneumatically actuated piston and cylinder device (13) for applying pulling force to the jaw mechanism. It is provided with a damping valve (22) for damping the flow of air from the piston and cylinder device (13) when the force is suddenly released on breaking of a rivet stem (23), thereby to reduce mechanical shock to the tool, and noise of fast-escaping air. The damping valve (22) comprises a resilient steel circular disc (32) which is secured at its center to the apex of a domed member (28) provided with vent holes (26). The undeformed shape of the disc (32) is flat. When, in use of the tool, a rivet stem breaks and the restraining force on the piston (15) is released, the velocity of air flow past the disc (32) urges the disc to bend towards the domed surface of the member (28), thereby restricting the air flow through the vents (26).

Abstract: A self-plugging blind fastener of the type having a tubular, headed, body, and a stem which is pulled and locked relative to the body to set the fastener, has improved locking means provided in the form of a deformable annular locking collar which is disposed on the stem, a locking groove on the plug part of the stem, and an annular recess at the head end of the body provided as an enlargement of the bore. The recess has a generally cylindrical outer region of substantially greater diameter than the main region of the bore, and a tapered inner region in which the diameter of the recess reduces to that of the main region of the bore. The recess can be stepped between the outer and inner regions.

Abstract: A hand-held pneumatically-powered breakstem rivet placing tool comprises a pulling head (12) driven by a pneumatic piston and cylinder device (13). The drive is transmitted by way of a chain (15), one end (45) of which is secured to the body (11) of the tool and the other end (49) of which is secured to the piston rod (35) of the pneumatic device. Between its two ends the chain forms a loop which passes over a roller (52) which is connected to the pulling head (12) by way of a link mechanism (54, 58). When the pneumatic device (13) is actuated, the movable end (49) of the chain is pulled down, thus pulling the roller (52) and driving the head (12) to place a rivet. The roller (52) is carried on the top of a plunger (56) which is continuously urged upwards by air pressure in the cylinder (63) in which it slides, thereby to return the mechanism to its original position after a rivet has been placed.

Abstract: A self-plugging blind fastener of the break-stem type, is suitable for fastening apertured sheets together, and comprises a headed tubular body and an elongate stem disposed in the bore of the body. The stem comprises a plug, and a stem-tail connected to the plug by a breakneck which is concealed by overlapping lips. The plug has a stop face, and an annular locking groove between the breakneck and the stop face. The body has a deformable locking collar upstanding above an adjacent region of the upper surface of the head. The diameter of the bore reduces, to provide a stop face and a locking region of smaller diameter, within the head. The fastener is set by pulling the plug into the bore until the stop faces meet, to form a blind head, and then deforming the collar to force the body to bulge into the locking groove of the plug.

Abstract: A self-plugging blind fastener of the break-stem type, is suitable for fastening apertured sheets together, and comprises a headed tubular body and an elongate stem disposed in the bore of the body. The stem comprises a plug, and a stem-tail connected to the plug by a breakneck which is concealed by overlapping lips. The plug has a stop face, and an annular locking groove between the breakneck and the stop face. The body has a deformable locking collar upstanding above an adjacent region of the upper surface of the head. The diameter of the bore reduces, to provide a stop face and a locking region of smaller diameter, within the head. The fastener is set by pulling the plug into the bore until the stop faces meet, to form a blind head, and then deforming the collar to force the body to bulge into the locking groove of the plug.

Abstract: A pin for a pin and swaged tubular member type of fastener has a shank (14) provided along nearly all of its length with identical combination locking, breakneck and pulling grooves (20). Each groove is provided on at least one sidewall with a discontinuity, and in a preferred embodiment both sidewalls of each groove are provided with discontinuity in the form of a displacement across the width of the groove and along the length of the pin. Alternatively the discontinuity may take the form of a change in inclination of the groove wall, or a combination of both such displacement and change in inclination.

Abstract: The improved split cycle engine comprises a compression unit 1 mechanically connected to an expansion unit 3 via shaft 2 and to a load via a coupling or centrifugal clutch 5, and a second compression unit 7 which is mechanically connected by shaft 9 to a second expansion unit 8. Compression unit 1 is fed by compression unit 7 and its output is fed to expansion unit 3 via a variable cut-off valve. Fuel is burnt in the air supplied by compression unit 1. The exhaust of expansion unit 3 feeds expansion unit 8. At high cut-off ratios shaft 9 rotates many times faster than shaft 2 and its relative speed is reduced as the cut-off ratio is decreased. At high cut-off ratios the torque output is substantially higher than that of a conventional internal combustion engine so that a complicated transmission is not necessary.

Abstract: A blind bolt is of the type comprising a tubular shell 14 through which extends a stem 13 with an enlarged head 12 at one end which, in installation of the bolt, is pulled into the shell 14 to expand it and form a blind head. The stem 11 is provided with two opposed deformations 19 to prevent the shell falling off the stem before installation. Each deformation has a relatively shallow sloping profile with its higher end towards the shell, and the width of the deformation is a maximum at the bottom end of the slope and a minimum at its higher end. The deformations are formed by pinching up portions of the stem between two opposed dies, the shape of the bite between the dies being tapered in the direction along the stem.

Abstract: A resilient seal 15 for the head 14 of a headed pin fastener member comprises an annular sealing bead 25, an annular boss 24 projecting on both sides beyond the thickness of the bead 25 and having tapered faces 29, 29, and a thin annular web 26 joining the parts 24 and 25. The symmetry of the seal enables it to be assembled on the pin either way round, with the same result.

Abstract: A two-part fastener intended for securing, e.g., a panel 41 to a frame member 42 comprises a tubular shell 11 and a pin 12. The shell bore contains a tubular insert or slug 14 of resilient nylon material. The exterior of the pin is formed with annular barbs 30. When the pin is inserted into the shell, the barbs 30 engage in the resilient slug 14 to secure the pin and shell together. The pin includes a removable pintail 33 which protrudes beyond the shell and assists in the pulling of the pin into the shell by means of a suitable pulling tool.

Abstract: A breakstem river installation tool includes a jaw mechanism (12) for gripping the stem of a rivet, and a pneumatically actuated piston and cylinder device (13) for applying pulling force to the jaw mechanism. It is provided with a damping valve (22) for damping the flow of air from the piston and cylinder device (13) when the force is suddenly released on breaking of a rivet stem (23), thereby to reduce mechanical shock to the tool, and noise of fast-escaping air. The damping valve (22) comprises a resilient steel circular disc (32) which is secured at its center to the apex of a domed member (28) provided with vent holes (26). The undeformed shape of the disc (32) is flat. When, in use of the tool, a rivet stem breaks and the restraining force on the piston (15) is released, the velocity of air flow past the disc (32) urges the disc to bend towards the domed surface of the member (28), thereby restricting the air flow through the vents (26).