Metal working – Means to assemble or disassemble – Valve applying or removing
Reexamination Certificate
2000-03-27
2001-12-18
Hail, III, Joseph J. (Department: 3723)
Metal working
Means to assemble or disassemble
Valve applying or removing
C029S213100, C029S278000, C029S280000, C029S238000
Reexamination Certificate
active
06330737
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a tool for mounting disk valves in motor cylinder heads, the disk valves being of the type that on its rod has a number of transversal, circumferential grooves for accomodating a corresponding number of beads on the insides of two substantially semi-circularly shaped locking bodies, which taper conically from the rear ends towards the front ends and which have the purpose of securing a locking ring against the valve spring, comprising a shaft, which in the region of one end has on one hand a spring-loaded tap, that is pressable into an outer cavity in the end portion of the shaft, and on the other hand two cross-sectionally vaulted clamping arms that are placed on opposed sides of the shaft, which clamping arms are articulatedly connected with the shaft and activated by at least one spring means that always strives to keep the arms swivelled inwards against the shaft, and against the action of which the clamping arms are pivotable outwards to a position distal from the shaft and the tap, the clamping arms in the region of the free ends having means for keeping said locking bodies in a given axial position relative to the clamping arms, in order to make possible a transfer of the locking bodies to the valve rod, more precisely by positioning the tap against the rod and pressing the same into the cavity of the shaft.
DESCRIPTION OF THE RELATED ART
A tool of the type referred to above is commercially available since a long time ago. According to this known tool, the holding means for the locking bodies consist of partly conically shaped seats in the region of the two free, front ends of the clamping arms. More specifically, the clamping arms consist of thin, punched and compression-moulded sheets of metal, which in connection with the compression moulding are shaped with a partly conical portion that at the back transposes into an axially straight (although cross-sectionally vaulted) portion and that tapers in a direction forwards from the transposition portion. The purpose of the individual seat is to accomodate the individual locking body in the same, with its external convex envelope surface being turned towards the inside of the seat and its concave inside turned towards the external envelope surface of the spring tap or the valve rod, respectively, and oriented parallel to the same. However, due to production-technical reasons, the semi-annularly shaped transposition portion between the rear end of the seat and the straight part of the clamping arm behind obtains a generally rounded shape, the sheet-metal in this transposition portion generally extending at an obtuse angle to the longitudinal extension of the clamping arm. In practice, this has the consequence that the tool functions in an insatisfactory way, more specifically due to the fact that forces are applied to the individual locking bodies, which forces tend to press the lower sharp edge on the front end of the locking body against the envelope surface on the valve rod. Therefore, when the locking body reaches the groove or grooves in the valve rod, this front edge tends to engage into the groove, before the beads on the insides of the locking bodies have engaged with the grooves. It is true that sometimes the front edge may slide past the groove, but too often it occurs precisely that the front edge gets caught in the groove. Some valve rods comprise only one single groove for engagement with one single bead on the inside of the locking body, while other rods may comprise several mutually separated grooves for engagement with a corresponding number of beads on the locking bodies. In the latter cases, the known tool is particularly difficult to handle, in that the front edges of the locking bodies easily get caught in the additional grooves, even if they by chance would slide past the first groove. Another deficiency of the known tool is that it is comparatively expensive to manufacture, inter alia due to the fact that each clamping arm requires its own screw compression spring, calling for separate assembling operations.
BRIEF SUMMARY OF THE INVENTION
The present invention aims at removing the above mentioned deficiencies of the previously known tool and creating an improved mounting tool for disk valves. Thus, a primary object of the present invention is to create a tool that in a reliable way is capable of bringing the locking bodies to a position, in which their beads may be smoothly brought into a distinct engagement with the groove or grooves in the valve rod, without the front edges of the locking bodies first tending to get caught therein. This shall be possible to realize independently of the number of grooves in the valve rod. Another object is to create a tool that is constructively simple and inexpensive to manufacture.
According to the invention, at least the primary object is attained by the features that are defined in the characterizing clause of claim
1
. Advantageous embodiments of the invention are further defined in the dependent claims.
REFERENCES:
patent: 4667388 (1987-05-01), Browning
patent: 5090102 (1992-02-01), Lovell
patent: 5097579 (1992-03-01), Pringault
patent: 5752308 (1998-05-01), Maley et al.
patent: 5761785 (1998-06-01), Connolly
patent: 5915740 (1999-06-01), Weitner
patent: 5996201 (1999-12-01), Ringle
patent: 392989 (1933-06-01), None
patent: 2 292 988 (1996-03-01), None
Hail III Joseph J.
Trego Maskin AB
Wilson Lee
Young & Thompson
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