DK148724B - Tilting foot with friction ball joint - Google Patents

Description

148724 - 1 -

The invention relates to a tilting foot with friction ball joints, in particular for a display terminal or similar utility, which must be freely adjustable by tilting and turning, and more particularly of the kind specified in the preamble of claim 1.

Known rocker feet of the kind in question, in which the rocker bed itself is constituted by a ball joint, are usually arranged in such a way that the fixation of the foot in a certain position is done by clamping a ball bowl together around a ball by means of a clamping mechanism, f. eg. in the form of a clamping screw. Handling of the rocker foot requires that both hands be free, the rocker foot must be held in position with one hand while operating the clamping mechanism with the other hand.

It has been attempted to use ball joints with constant frictional force, so that the tilting foot can be adjusted with one hand alone, the adjustment being done by overcoming the frictional force in the joint. Ball joints of this type have an unfortunate tendency to loosen or wear out excessively quickly during use, thereby causing the joint to become too loose to ensure the necessary self-restraining effect that is a prerequisite for the reliable function of the rocker foot.

The object of the invention is to provide a tilting foot which can be operated with one hand alone and which is not affected by the above disadvantages. This is achieved according to the invention by arranging the ball joint as set forth in the characterizing part of claim 1. The lining of the ball cup (bearing cup) with a low friction bearing material of plastic such as e.g. The purpose of high density polyethyl tetrafluoroethylene or polyethylene is to provide the ball joint with a suitable low frictional force, regardless of the fact that the ball cup is given a considerable bias. The hardened and ground ball causes poor wear on the liner and at the same time reduces the stick-slip effect, which is a prerequisite for the easy handling of the rocker foot. In summary, it can be said that the ball joint according to the invention has the optimum combination of relatively large friction (= self-restraint) and low stick-slip (= low adjusting force).

- 2 - 1Λ8724

A particularly smooth ball surface is obtained according to the invention by hard chromium and subsequent grinding. The surface quality of the ball is crucial for the durability of the relatively soft bearing lining.

The invention will be explained in more detail in connection with the drawing, in which fig. 1 shows a tilting foot according to the invention in vertical section; FIG. 2 is an enlarged sectional view showing the ball head of the rocker foot; and FIG. 3 tilting foot as seen from the side in the tilted position.

In the embodiment shown in the drawing, the rocker foot consists essentially of a foot plate 1, a vertical threaded spindle 2 with a ball head 3 at its upper end and an angular adjustable support plate 4 for the object to be carried by the rocker foot, e.g. a display terminal.

The foot plate 1 is provided with a threaded guide 1a for the threaded spindle 2. The spindle serves to adjust the height of the rocker foot in the usual manner. The threaded spindle carries at its upper end the ball head 3a. This is enclosed by a bearing bowl 3b which is inserted into a cylindrical socket 5. The socket is provided with two radially directed clamping screws 6 which tighten. towards the outside of the bearing bowl 3b. The clamping screws provide the ball head with the required bias. The two screws 6 are mutually offset 90 °.

The socket 5 is welded to the underside of the support plate 4.

A cylindrical collar 7 encloses the ball head 3, and a correspondingly smaller collar 8, which is attached to the spindle 2 immediately below the ball head, encloses this and the upper part of the guide 1a. The two collars 7 and 8 serve primarily aesthetic considerations. The lower collar 8 is used as a grip for height adjustment of the rocker foot.

The ball head 3 is shown in an enlarged section in FIG. 2nd

The ball itself 3a is made of hardened and ground steel. The ball which is pierced is pressed on the threaded spindle 2. The bearing 3b is lined with e.g. PTFE (polytetrafluoroethylene with the trade name Teflon) or PE-HD (high density polyethylene or low pressure polyethylene) and this liner 3c is put under compression between the ball and the bearing bowl by the said radial screw bias. The compression results in the desired friction effect, which is a prerequisite for the self-fixing ability of the bearing.