Chairs and seats – Movable back
Patent
1997-12-19
1999-03-23
Brown, Peter R.
Chairs and seats
Movable back
248412, A47C 740
Patent
active
058849696
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to a release for a height adjustment for back rests.
Such a height adjustment for back rests of chairs, in particular office chairs, consisting of a housing in which a flat back rest carrier is held by a detent ball clamping arrangement, whereby the back rest carrier is provided in axial direction with successively arranged indentations or openings for detent balls which are held in the indentations or openings by a spring-loaded clamping bevel, and whereby a push button that extends laterally from the housing can be used to move the clamping bevel against the elastic force to disengage it, is known, for example, from EP-A-O 264 555.
The objective of the present invention is to create a release for a height adjustment of the type mentioned above in which the same mechanics are simply equipped with different push-buttons and which also forms a unit without push-buttons, from which no parts are lost.
Further developments and advantageous embodiments of the invention are described hereinafter.
According to the invention, fastened in the housing is a base plate which is provided with a groove arranged approximately in the axis of the push-button and which has a narrower section for the end of the push-button with which the same is inserted in the housing and the base plate. Following the narrower section, the groove has a wider section in which a shuttle, which contains the clamping bevel for the ball and which is wider than the narrower section of the groove, is slidably guided by the push-button against the force of a spring which is supported at the end of the groove opposite the push-button. The step at the transition from the narrower to the wider section of the groove serves as a stop for the shuttle.
Advantageously, the push-button is provided with a recess inside the housing in which a spring, catch or some such is engaged in the base plate. According to a preferred embodiment of the invention, the spring, catch or some such is inseparably engaged against the pull of the push-button.
The invention is described below by way of example and with reference to the drawings, in which:
FIG. 1 to 3 show three views of a height adjustment including a top view in FIG. 1 with the upper housing part cut away, in FIG. 2 a section along the line A--A, and in FIG. 3 a section along the line B--B of FIG. 1;
FIG. 4a to 6c show separate components from FIG. 1.
The height adjustment according to FIG. 1 to 6c consists of a flat housing 1, with a substantially rectangular cross section, in which a flat back rest carrier 2 is slidably guided and can be clamped. The housing can be extended at the bottom and connected to a seat carrier. It can also have different dimensions than those shown, and it can have a curved shape.
Along its center axis, back rest carrier 2 is provided with a number of holes 3 which define the insertion depth. In one of these holes 3 is a detent ball 4 which is pressed into the hole by a clamping bevel 5' of a shuttle 5. The pressure results from a spring 6 which is supported in a base plate 7 fastened in housing 1, for example by means of screws 17 or catches. Base plate 7 is provided with a groove 16 in which the shuttle 5 can slide and on which the side opposite spring 6 comes to a stop. On this side, shuttle 5 is adjoined by a push-button 8 with which it can be pushed back against the force of spring 6, upon which clamping bevel 5' releases the ball 4, and the back rest can be moved until the desired insertion depth is reached, and the push-button 8 is released again. Push-button 8 has a flat recess 8' in which a small spring 9 engages during installation, which means that push-button 8 can no longer be pulled out. This measure prevents the unintentional release of push-button 8 and provides an opportunity to insert different shapes of push-buttons in the same height adjustment without problem. Since the base plate 7 is preferably made of plastic, a metal washer 21 is inserted in the area where the detent ball 4 pushes against the clamping bevel 5', to ensure pro
REFERENCES:
patent: 1075323 (1913-10-01), Benjamins
patent: 1101552 (1914-06-01), Hume
patent: 3467352 (1969-09-01), Bohler
Brown Peter R.
Sifa Sitzfabrik GmbH
LandOfFree
Release for a height adjustment of back rests does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Release for a height adjustment of back rests, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Release for a height adjustment of back rests will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2119196