Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
275 words
Apparatus for reducing the compression of an internal combustion engine which has a camshaft (1) carrying an inlet valve cam (4) and an exhaust valve cam (5) and tappets (2, 3) engaged with those valves, characterised in that the apparatus comprises a supporting member (6) secured to, and rotating with, the camshaft (1); a decompression device (9) having a shaft (10) which is rotatably supported in the supporting member (6) and which has a decompression cam (12) formed thereon, the decompression cam (12) being engageable with the tappet (2 or 3) of either the inlet valve cam (4) or the exhaust valve cam (5) to cause lifting of the tappet; and a weight (13) which is rotatably mounted on the supporting member (6) so as to be subject to centrifugal force on rotation of the camshaft (1) and which is operatively engaged with the decompression device (9) so that rotation of the weight (13) is accompanied by rotation of the decompression device (9); the weight (13) and the decompression device (9) being so arranged that, when the rotational speed of the camshaft (1) is below the speed which causes reverse engine movement, the periphery of the decompression cam (12) projects beyond the periphery of the valve cam (4 or 5) to open the corresponding valve in order to reduce the compression of the engine, and that, when the rotational speed exceeds the speed which cause reverse engine movement, the periphery of the decompression cam (12) is retracted to or below the periphery of the valve cam (4 or 5) to close the valve during at least a part of the compression stroke of the engine.
Claim 2
Dependent Claim
275 words
Apparatus for reducing the compression of an internal combustion engine which has a camshaft (1) carrying an inlet valve cam (4) and an exhaust valve cam (5) and tappets (2, 3) engaged with those valves, characterised in that the apparatus comprises a supporting member (6) secured to, and rotating with, the camshaft (1); a decompression device (9) having a shaft (10) which is rotatably supported in the supporting member (6) and which has a decompression cam (12) formed thereon, the decompression cam (12) being engageable with the tappet (2 or 3) of either the inlet valve cam (4) or the exhaust valve cam (5) to cause lifting of the tappet; and a weight (13) which is rotatably mounted on the supporting member (6) so as to be subject to centrifugal force on rotation of the camshaft (1) and which is operatively engaged with the decompression device (9) so that rotation of the weight (13) is accompanied by rotation of the decompression device (9); the weight (13) and the decompression device (9) being so arranged that, when the rotational speed of the camshaft (1) is below the speed which causes reverse engine movement, the periphery of the decompression cam (12) projects beyond the periphery of the valve cam (4 or 5) to open the corresponding valve in order to reduce the compression of the engine, and that, when the rotational speed exceeds the speed which cause reverse engine movement, the periphery of the decompression cam (12) is retracted to or below the periphery of the valve cam (4 or 5) to close the valve during at least a part of the compression stroke of the engine.
Claim 3
Dependent Claim
50 words
Apparatus according to claim 1, wherein the valve cam (4 or 5) has a recess (4a) in a part of its periphery such that the contour of the valve cam is unaffected, and the decompression cam (12) is located in the recess (4a) of the valve cam (4 or 5).
Claim 4
Dependent Claim
17 words
Apparatus according to claim 1 or claim 2, wherein the supporting member (6) is a cam gear.
Claim 5
Dependent Claim
19 words
Apparatus according to any one of the preceding claims, wherein the decompression cam (12) has a semicircular cross section.
Claim 6
Dependent Claim
28 words
' Apparatus according to any one of the preceding claims, wherein the decompression cam (12) is operatively engageable with the tappet (2) of the inlet valve cam (4).