Joints and connections – Distinct end coupler – Separate screw or pin-type connections
Reexamination Certificate
1998-09-18
2001-02-13
Browne, Lynne H. (Department: 3629)
Joints and connections
Distinct end coupler
Separate screw or pin-type connections
C403S347000, C403S281000, C403S282000, C403S283000, C029S509000
Reexamination Certificate
active
06186696
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns the pressing of an at least locally cylindrical part into a tubular part in a cruciform arrangement, i.e. the pressing of this at least locally cylindrical part into the tubular part globally transversely to the lengthwise direction of the latter.
By “at least locally cylindrical part” is meant here a part the exterior surface of which is, at least locally where it is pressed into the tubular part, a cylindrical surface, i.e. a surface which, regardless of the circular or other nature of the contour of its cross-section, is formed of parallel generatrices.
This at least locally cylindrical part, which for convenience will be referred to hereinafter simply as the cylindrical part, can be solid, hollow or tubular.
In the case of a hollow or tubular part it can serve as a housing for at least one other component of any kind.
By “tubular part” is meant here a part which, whilst being globally elongate in the form of a tube, being open at one end at least, can be shaped to a greater or lesser degree, for example more or less curved or bent, and which has any cross-section.
BACKGROUND OF THE INVENTION
The assemblies formed of a cylindrical part pressed into a tubular part of the above kind in a cruciform arrangement can have applications in themselves, in particular by virtue of the particular assembly of the parts that constitute them, but they can also find applications in assembling other components connected to one or other of these parts, for example in automobile construction.
To enable them to be assembled by pressing, a hole is formed through the tubular part, perpendicular to its lengthwise direction and adapted to envelope the overall contour of the cylindrical part, and the cylindrical part and the tubular part are conjointly subjected, for example in a press, to a relative movement such that the cylindrical part is forcibly inserted into the hole in the tubular part from one side of the latter with the tubular part braced externally on the opposite side.
Various problems have to be overcome in carrying out pressing operations of this kind.
Firstly, to avoid deformation of the tubular part when the hole is formed in it, a machining process is normally required, with the cost penalty of using relatively complex and costly tooling.
Then, the tubular part forming two walls around its hole, by virtue of its tubular structure, the wall which is on the side from which the cylindrical part is inserted is the first to be subjected to the pressing force and therefore can itself be subject to some deformation.
If this occurs, the cross-section of the tubular part is modified around its hole and this can compromise the quality of the mechanical joint between it and the cylindrical part and therefore the durability of the assembly.
In any event, the resulting visible deformation of the tubular part is bound to cast some doubt on this durability and the assembly must therefore normally be discarded.
Furthermore, even in the absence of any deformation of either wall of the tubular part, the surface area of contact between the tubular part and the cylindrical part is reduced to that of the edge of the walls of the tubular part around its hole.
The quality of the mechanical joint is dependent on this contact surface area.
In practice, in some applications at least, in which the parts concerned are subject to a tear-out force and/or to vibrations, the contact surface area may be insufficient to assure a durable assembly.
To overcome this latter problem at least in part, Swiss patent No. 383 303 proposes the formation of an upstanding rim around the hole in at least one of the walls of the tubular part, in practice in both of them.
According to the above Swiss patent the tooling used for this purpose is a punch with a pointed end in the form of a blade so that, to form the upstanding rim, the wall concerned is simply pushed back laterally on either side of this blade.
As a result the upstanding rim obtained does not extend around all of the perimeter of the hole that it borders and its height varies between the two ends of the diameter of the hole, from a zero height at these two ends to the detriment of the reinforcement.
Moreover, and most importantly, the risk of deformation of one or other of the walls of the tubular part during pressing of the cylindrical part into the hole in the latter is virtually unchanged.
SUMMARY OF THE INVENTION
An aim of the present invention is an arrangement whereby such deformation can be prevented and which further yields other advantages.
To be more precise, it consists firstly in a method of pressing an at least locally cylindrical part, referred to herein for convenience as the cylindrical part, into a tubular part, globally transversely to the latter, this method being of the kind in which, a hole in the tubular part that has substantially the overall contour of the cylindrical part adapted to pass completely through both of two walls of the tubular part that the tubular part forms globally transversely around it, there is formed, over at least a portion of the perimeter of this hole, for at least one of the walls of the tubular part, an upstanding rim which, attached to this wall, extends towards the other wall of the tubular part, and the cylindrical part and the tubular part are conjointly subjected to a relative movement as a result of which the cylindrical part is forcibly inserted into the hole into the tubular part from one side of the latter while the tubular part is braced externally on the opposite side, and being generally characterized in that prior to formation of the upstanding rim on the tubular part, there is inserted into the latter a spacer adapted to brace it internally in the vicinity of its hole over at least a portion of the perimeter of the latter.
This spacer prevents any deformation of the wall of the tubular part at risk of such deformation, i.e. the wall on the side from which the cylindrical part is inserted.
Because of the upstanding rim bordering the hole in the tubular part, the surface area of contact between the tubular part and the cylindrical part is significantly increased, to the benefit of the durability of the assembly, and an upstanding rim of this kind is preferably formed on both walls of the tubular part around the entire perimeter of the corresponding hole, and with a substantially constant height all around the latter.
The upstanding rim or rims employed in this manner can be formed by punching, the spacer inside the tubular part forming therein a die enabling such punching without deformation of the wall concerned.
In accordance with the invention, additional benefit may be obtained from this spacer when forming the required hole.
For this purpose, the spacer is placed in the tubular part before the hole is formed and a hole, in this instance a preliminary hole, is simply punched out of the tubular part.
Unlike the tooling used for machining, the tooling used for is advantageously very simple and inexpensive.
It has the further advantage that there is no problem of swarf and is not subject to wear.
Finally, this tooling is advantageously suitable for use on a standard machine, in this instance a simple press, and more particularly on a simple hydraulic press, requiring no specific modifications.
The overall result of this is great economy of use and manufacture.
The present invention further consists in tooling suitable for implementing the method in accordance with the invention and any assembly resulting from such implementation comprising two parts pressed together in a cruciform arrangement, namely an at least locally cylindrical part and a tubular part having a transverse hole in it in which the at least locally cylindrical part is forcibly inserted.
In accordance with the invention, an assembly of the above kind is normally advantageously free of any deformation, the spacer internally bracing the wall of the tubular part on the side from which the at least locally cylindrical part is inserted into the hole in the tubular part.
REFERENCES:
patent
Browne Lynne H.
Garcia Ernesto
Vallourec Composants Automobiles Vitry
Young & Thompson
LandOfFree
Method for the crosswise shrinking of a cylindrical part in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the crosswise shrinking of a cylindrical part in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the crosswise shrinking of a cylindrical part in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2591419