Joints and connections – Rigid angle
Patent
1987-06-05
1989-03-07
Kundrat, Andrew V.
Joints and connections
Rigid angle
403231, 403245, B25G 300
Patent
active
048101273
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a mounting for connecting two furniture parts. Such a mounting is formed of a clamping part which can be fastened to a first furniture part and which comprises a locking head and a rotating lock which is insertable in a cylindrical recess of the second furniture part and is of a substantially cylindrical shape and has at least one approximately helically extending inner clamping cam which engages behind said locking head.
Mountings of this type are known per se.
However, the known mountings have the disadvantage that they can be loosened due to vibrations of the means of transport, which occur during transportion.
Attempts were made to prevent this disadvantage either by constructing the inner clamping cam in a wave-shaped manner so that a catching effect was brought about between the mounting parts or by providing saw-toothlike teeth on the outer surface of the rotating lock.
With the outer teeth, the entire restoring moment was exerted on the bearing surface; i.e., the occurring forces had to be removed from the outer surface of the rotating lock, wherein the saw-teeth worked into the work material of the furniture like a circular saw because of the occurring vibrations, so that the connection loosened.
The wave-shaped teeth on the inner clamping cam were also insufficient by themselves for preventing the undesired loosening of the connection.
SUMMARY OF THE INVENTION
The present invention has the object of avoiding the aforementioned disadvantages and improving a connecting mounting of the type mentioned about in such a way that the risk of unintended loosening, particularly during transportation, is reduced or prevented.
This object is met, according to the invention, in that the inner clamping cam has toothlike raised portions or recessed portions, and the circumferential surface of the rotating lock is provided at least partially with projections formed as ribs or raised portions.
The loosening moment can be increased in the mounting by means of simple and inexpensive steps in such a way that an unintended loosening is made substantially more difficult or is prevented.
Attempts with mountings in commercially available chip boards of medium quality with a uniform tightening moment of the rotating lock of 3 Nm, (Newton-meter) for example, have resulted in the following: 1. If neither an inner clamping cam nor a rotating lock with toothlike raised portions/recessed portions are provided, the loosening moment of the rotating lock is between 1.0 and 1.4 Nm. The loosening moment is a turning moment which is required for loosening the mounting connection. 2. If the rotating lock is provided with toothlike raised portions/recessed portions, the loosening moment of the rotating lock is between 1.8 and 2.3 Nm. 3. If only the inner clamping cam is provided with tooth-like raised portions/recessed portions, the loosening moment is between 1.8 and 2.4 Nm. 4. If the inner clamping cam and circumferential surface of the rotating lock are provided with toothlike raised portions/recessed portions, the loosening moment is between 2.4 and 2.6 Nm.
As shown above, the loosening moment can be increased almost to the value of the tightening moment by means of the combination of toothlike raised portions/recessed portions on the inner clamping cam as well as on the circumferential surface of the rotating lock. The tightening moment is a turning moment which must be applied for the purpose of producing a proper connection of the mounting parts.
It has proven particularly advantageous to construct the ribs or raised portions on the circumferential surface of the rotating lock as saw-teeth, wherein the saw-teeth are directed opposite to the locking turning direction of the rotating lock, i.e. the saw-teeth oppose a greater resistance to the loosening turning direction of the rotating lock in that they dig into the work material of the furniture part with their tips in this turning direction.
Moreover, it has proven advantageous that the raised portions/recessed portions
REFERENCES:
patent: 4131376 (1978-12-01), Busse
Kundrat Andrew V.
Striker Michael J.
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