| 摘要 |
<p>A pressure cap for a vehicle cooling system consists of two plastic sleeves, the outer one 1 of which has threads 3,4 engaging a filler neck and the inner one 2 of which has a seal 6 for sealing against the filler neck. The inner sleeve contains the pressure relief valves. The inner and outer sleeves are secured together by a simple mechanical means consisting of four lugs 12 provided at the top of the inner sleeve, each lug being provided with a resilient tag 14. During assembly, the inner sleeve is inserted in the outer sleeve with the lugs in alignment with lobes 4 in the outer sleeve. The inner sleeve is then rotated, and this resiliently deflects the tags 14 inwards. By the time that the inner sleeve has been rotated in a clockwise direction to the position shown in Figure 4, the tags are level with a lobe and can spring outwards and prevent reverse rotation of the inner sleeve. The parts are then locked together since an inclined circumferential cam surface and cam follower (not shown) prevents any further rotation of the inner sleeve in a clockwise direction relative to the outer sleeve.</p> |
