Patent GB-1405671-A (GB)
Title: Valve spring caplock assemblies
IPC: F01L3/10
Filed: 1972-08-21
Abstract: 1405671 Assembling I.C. engine valves TRW Inc 21 Aug 1972 38919/72 Heading B3A [Also in Division F2] A method of automatically assembling and locking a valve spring retainer assembly which includes a cap 11b with a tapered well 14b having a segmented internally beaded valve lock 12, 13 received therein, the cap having a valve spring engaging flange, on to a grooved valve stem surrounded by a valve closing spring which comprises the steps of: feeding the assembly with the small end of the tapered well leading on to the valve stem while depressing the valve spring with the flange, thrusting the end of the stem against the lock in the well to shift the lock towards the large end of the well, retarding the shifting of the lock while continuing the thrusting of the valve stem thereagainst to move the stem into the lock and spread the lock segments apart, arresting the spreading of the lock, moving the valve stem through the lock segments until the stem groove is aligned with or beyond the internal bead of the lock and reversing the feeding of the assembly to expand the depressed valve spring for moving the tapered collar into wedged engagement with the valve lock constricting the lock segments around the valve stem, thereby securing the assembly to the stem with the lock beads seated in the groove and the locks forming a wedge connection between the valve stem and the cap. A rotatable bearing member 16 may be provided between the locks 12 and 13 and the cap 11, as shown in Fig. 1. To facilitate assembly of the cap and locks to a valve stem, a sub-assembly is formed by passing a plastics tube 26, having a lip 27 at one end, through the locks and cap and flaring the end of the tube at 29 to engage the cap. The sub-assembly is automatically assembled to a valve stem by using the tool shown in Fig. 6, which also shows the valve stem 111 and the valve spring 110. The body 61 of the tool, has a recess 70 which receives the cap, and is acted on by a ram 114 which pushes the tool down so that the valve stem engages the end of the plastics tube and lifts the tube and locks until the locks engage the lower end of a spring-loaded plunger 92. As the valve stem continues to move through the cap, the plunger is raised until the upper end of a piston 80 engages a plate 66 forming part of the body, so that the locks are positioned in a frusto-conical recess 73 in the body. Further movement of the locks being then prevented, the tube is pushed upwardly through the locks into the interior of the plunger. The movement of the ram 114 is reversed and the plunger 92 pushes the locks downwardly relative to the valve stem and cap, into the well in the cap, so that an inwardly projecting rib 25 on the locks engages a cannelure in the valve stem. In a modification, Fig. 13, the locks are formed with a plurality of ribs 127, which engage corresponding grooves in the valve stem. A tool for assembling this type of lock has to ensure that the ribs are engaged in the correct grooves, and to this end the plunger 192, Fig. 14, contains a pilot pin 202 which is spring-loaded to move towards the valve stem, but which can be locked in a retracted position, by a detent 204 which cooperates with a groove 205 in the shank of the pilot pin. This retracted position of the pilot pin is reached by the end of the valve stem pushing the pin into the plunger to an extent such that the grooves in the valve stem are correctly positioned relative to the ribs on the locks, which have been removed axially into a recess 173 in the body of the tool.