Electricity: conductors and insulators – Conduits – cables or conductors – Single duct conduits
Reexamination Certificate
1999-01-07
2001-02-27
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Single duct conduits
Reexamination Certificate
active
06194659
ABSTRACT:
The present invention is generally concerned with cable entry devices used to pass a cable of any kind through a wall of any kind to which it is sealed, for example for a cable to enter an enclosure of any kind such as a case, cabinet or other enclosure of such type in a sealed manner.
It is more particularly concerned with cable entry devices having a seat with an opening through which the cable is passed and an engagement portion extending annularly around the axis of the opening in the seat, the engagement portion having an outside wall that extends toward the front and connecting it to the seat and an inside wall, set back toward the rear relative to the outside wall, connected to the latter in a U-shape arrangement.
A cable entry device of the above kind is described in French patent application No. 2 402 323 filed as application No. 77 26710 on Sep. 2, 1977.
In the above French patent application the entire device is made from an elastically deformable material.
Although an arrangement of the above kind is effective in terms of providing the required seal, the mechanical retention of the cable is relatively mediocre.
International patent application No. W
0
96/28862 proposes the use of jaws to assure this mechanical retention.
However, in the above international patent application the jaws are in a separate chamber which leads to a relatively complex overall construction.
Furthermore, the corresponding cable entry device being made as two shells which together form a globally parallelepiped-shape assembly, only two jaws can be provided and for the required mechanical retention to be satisfactory in spite of this the jaws are in practice in the form of self-wedging catches which further complicates overall construction.
German patent application No. 35 33 418 counterpart U.S. Pat. No. 4,686,738 also propose the use of jaws, in practice more than two jaws which are circumferentially arranged about the axis of the assembly and separated from each other by slots.
The jaws relate only to the inside wall of the engagement portion, however.
They are therefore relatively short.
They are also substantially rectilinear.
As a result, on the one hand, they are operative essentially through their stiffness, like the claws of a washer with its inside periphery divided into claws, which reduces the range of acceptable cable diameters, and, on the other hand, they have to be used in conjunction with actuator means, in this instance fingers forming part of the seat, and this leads to a relatively complex construction in which, formed on a component separate from the seat, the engagement portion is mobile axially relative to the seat, in practice screw-fashion.
Although the above German patent application also discloses a seal, the seal is in the form of a ring to be clamped onto the cable concerned, which implies the use of particular cam arrangements.
In European patent No. 0 753 918, in which the engagement portion is reduced to a single cylindrical wall, the jaws are also in the form of relatively rigid tongues, to be more precise in the form of plates, and each is articulated to the seat by a thinner area forming a hinge which in practice is tangential to a circumference concentric with the axis of the opening in the seat.
However, as previously, the jaws are relatively short and substantially rectilinear so that, also as previously, they are operative essentially through their stiffness, to the detriment of the range of acceptable cable diameters.
Also, ribs must be provided inside the engagement portion to provide them with additional support when necessary and project radially, to the detriment of the available cross section of the engagement portion.
Finally, in European patent application No. 0 753 918 there is no sealing member.
A general aim of the present invention is an arrangement which overcomes the above drawbacks.
To be more precise, the present invention consists in a cable entry device of the kind including a seat which has an opening through which a cable can be passed and an engagement portion which extends annularly around the axis of the opening in the seat, this engagement portion having an outside wall which extends toward the front and which is joined to the seat and an inside wall set back rearwardly relative to the outside wall and joined thereto in a U-shaped configuration, characterized in that, conjointly, the engagement portion is circumferentially divided into elastically deformable jaws by slots that extend as far as the seat, in that, where they join onto the seat, the jaws are each embedded therein in a root area tangential to a circumference concentric with the axis of the opening in the seat, and in that the engagement portion which is made of a relatively rigid material is associated with a sealing member globally transverse to the axis of the opening in the seat, at least partly shutting off that opening and made of a relatively flexible material.
Because of their shape and size, and because of the manner in which they are connected to the seat from which they arise, the jaws of the cable entry device in accordance with the invention are essentially operative in bending when a cable is engaged between them.
They therefore cater for a wide range of cable diameters of which they provide effective mechanical retention.
More generally the arrangement in accordance with the invention, which lends itself to many different embodiments, has the advantage of reconciling good mechanical retention of the cable with a good seal around the cable.
REFERENCES:
patent: 3941917 (1976-03-01), Barrow et al.
patent: 4375011 (1983-02-01), Grunau
patent: 4490576 (1984-12-01), Bolante et al.
patent: 4600803 (1986-07-01), Holzmann
patent: 4686738 (1987-08-01), Bladh
patent: 4738636 (1988-04-01), Bolante
patent: 5557073 (1996-09-01), Truesdale, Jr. et al.
patent: 384 654 (1964-11-01), None
patent: 35 33 418 (1986-04-01), None
patent: 2 402 323 (1979-03-01), None
patent: WO 96/28862 (1996-09-01), None
Legrand
Reichard Dean A.
Young & Thompson
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