Method for producing panels ribbed on one or both sides   

The present invention relates to a novel method for the production of washers ribbed on one or both sides, i.e. washers having a rib profile on one or both sides of the washer.

Such washers being ribbed on one side and washers being ribbed on both sides are known for many years. Especially washers being ribbed on both sides which for example are described in the EP-B1-426 895 have shown to be effective as a good safety measure against loosening by unscrewing.

This prior art is having the disadvantage of a comparatively large scale and followingly expensive production method which up to now was necessary for such washers. The general procedure in the mass production of these members is the embossing of the rib profile. Until now only by the use of this production method an optimal rib profile is achievable which for the desired safety function is absolutely necessary.

This necessary expenditure in the mass production according to the prior art substantially is increasing the production costs. Especially in connection with trial samples and prototype members the tool costs are so high that they are discouraging the user. The tool costs for trial samples and prototype members according to the prior art namely are insignificantly lower compared with the costs for the production of corresponding series tools.

Followingly it is the task to be solved by the invention to provide a method for the production of washers being ribbed on one or on both sides which substantially is less expensive and which especially the costs of the production of trial or prototype members are substantially lower.

According to the invention, this task is solved by the feature that the rib profile is produced by rolling. The profile either can be embossed previously in the raw material or later on the smooth punched out washer.

It is especially preferred in this connection if the rolling of the rib profile is done on the raw material of the washers and that the washers only after the rolling of the rib profile are punched out. In this way with a single pair of rolls a broad range of embodiments of washers can be produced. According to this advantageous embodiment of the invention with the same rolling tools different embodiments of the washers can be produced in which the interior and exterior diameter deliberately can be changed without new embossing tools being necessary as this is true for the prior art.

It is especially preferred to produce the rib profile by embossing rolls.

An especially efficient method of production is achieved preferably in the case when the rolling of the rib profile is done by two synchronously running rollers or roller segments. Rollers(-pairs) and roller segments, too, can be used for performing the embossing.

Preferably the pattern for the rib profile can be provided on the rollers for rolling in a raised or recessed way.

According to the invention the production of the ribbed washers is done by rolling the profile. In this connection the rolling preferably is done by embossing rollers. The tools and apparatuses for this method of production according to the invention significantly are less expensive compared with the tools and apparatuses necessary for the embossing process according to the prior art. Namely in the rolling process caused by the line-shaped contact between the rolls and the work piece only comparatively small forces are necessary. Preferably in this connection the forming of the rib profile can be done by two synchronously running rollers. The rib profile can be provided on the rollers for rolling in a raised or recessed way. Following the rolling process the punching out of the washers is done. In this way from the same material already provided with the necessary ribs washers with a deliberate interior diameter and exterior diameter can be produced. This can be used for the cost saving production of smaller amounts. In connection with large numbers the washer profiles in a multiple way are positioned side by side to minimize the consumption of materials. A further possibility for production is achieved by first punching out the washers and then feeding the same in the correct position to a profiled pair of rollers.

According to the prior art until now only ribbed washers are produced manufactured on embossing machines. According to the invention due to the line-shaped contact of the rolls substantially lower forces are necessary. Followingly smaller production machines can be used for the punching out and the production costs are substantially lower. The achieved price reduction will motivate the user of the parts to increasingly use this safety system.

A further advantage of the production method according to the invention is a more uniform rib profile on both sides of the safety washers in case washers are produced being ribbed on both sides. While in connection with embossed washers being ribbed on both sides on one side the rib profile completely is rounded due to the embossing process on the opposite side a small flattening of the radius of the ribs can be recognized. It is true that this flattening according to the prior art can be kept within the limits of tolerances. Nevertheless this is leading to small dispersion in connection with the mounting thereof. In connection with the rolled embodiment of the washers ribbed on both sides according to the invention the rib profile on both sides is equally well rounded.

Especially the advantage with regard to costs is shown in connection with the production of trial members or prototype members.

By means of the production method according to the invention with a singular pair of rollers a broad range of embodiments of washers can be produced. With the same rolling tools different embodiments of washers can be produced, wherein the interior diameter and exterior diameter of the washers can be deliberately varied.