GB2119641A

GB2119641A - An improved seat

Info

Publication number: GB2119641A
Application number: GB08312833A
Authority: GB
Inventors: Karl Zund
Original assignee: Zuend & Co AG K; KARL ZUND AND CO AG
Current assignee: Zuend & Co AG K; KARL ZUND AND CO AG
Priority date: 1982-05-10
Filing date: 1983-05-10
Publication date: 1983-11-23
Also published as: ATA181182A; GB8312833D0; AT378320B; GB2119641B

Abstract

A seat comprises a seat carrier 4 and a back rest 5 pivotable relative to one another about an approximately horizontal axis 6. A gas compression spring 36 is provided for the return or restoring movement and for optional positional location. There is a further spring 34 against which, in the rearward pivoted end position of the back rest, a part of the back rest, seat carrier and/or gas compression spring abuts thereby acting as a buffer. The further spring may be a leaf spring (30, Fig. 1), a helical tension or compression spring or a torsion spring. <IMAGE>

Description

SPECIFICATION An improved seat The invention reiates to a seat having a seat surface and a back-rest, in which at least one support member of the seat surface and the backrest are adjustable in dependence upon one another in relation to a seat carrier connected to the pedestal and are respectively pivotable about an approximately horizontal axis, and a gas compression spring is provided for the return movement and for optional positional location, which gas compression spring is in operative connection at one end with the seat carrier and at the other end with the back-rest, while at its end on the back-rest side the gas compression spring is pivotably secured to a push lever engaging on the back-rest.

A seat of the aforementioned type is disclosed in the Applicant's prior Austrian Patent Application A 1244/81 published on 19820115.

In this published application, the drawings and specific description disclose that a gas compression spring is provided and, additionally, a helical compression spring. Tests have shown that for a simple rocking movement in the use of such a seat, it is quite sufficient to provide only one gas compression spring, which is achieved in particular by the design with a pivotably mounted push lever and a lever arm mounted pivotably on the seat carrier at a distance from its pivot axis on the back-rest.With the additional provision of a helical compression spring which is already brought into action at the start of the tilting movement of the back-rest and the force of which increases substantially during the tilting procedure, it has proven to be a disadvantage that the force arising increases enormously in the rearward range of the tilting movement, so that a genuine rocking movement could in practice only be fully utilised by relatively heavy persons. In contrast, in these thorough tests it was ascertained that a pure rocking movement can be achieved more simply and more comfortably if only one gas spring correspondingly influences the rocking range.

DE-PS 27 33 322 also discloses an embodiment with a gas compression spring and a compression spring, which are mutually supportive for the entire range of the rocking movement. Since in such a design the displacement travel of the springs is much greater than in the previously described embodiment, the described action is further intensified because the compression spring has to be compressed in a greater travel range, so that its spring force is increased enormously towards the rearward-end pivoted end range of the back-rest.

DE-OS 1 480 485 discloses a passenger seat with a back-rest which can be fixed in position rearwards against spring force hingelessly and steplessly, wherein for the adjusting motion there is likewise provided at least one tension or compression spring, in which case a compression spring may also be designed as a gas spring. In such an arrangement, to prevent any engagement of metal parts, rubber plugs are provided, against which the adjustable parts abut in their end position. These rubber plugs bring about in practice merely a noiseless contact against one another of the individual movable parts and of the stationary parts, but otherwise they are of no significance.

Tests have shown that, for carrying out a satisfactory rocking motion with a seat of the initially mentioned type, the provision of one gas compression spring is sufficient, since uniform tilting with approximately constant reaction is thereby made possible. However, it has also been shown that when utilising the whole displacement possibility, the gas spring reaches its end position relatively abruptly, so that precisely in this end range the rocking movement is found to be uncomfortable. Moreover, the action of the gas compression spring is reduced precisely in this end range as a result of changing leverages, so that in this latter range of the displacement motion the back-rest comes under influences interfering with the rocking movement.

Therefore, the invention is based on the object of devising a possibility which, on the one hand, without particular exertion enables the entire displacement range of a seat or the back-rest of a seat to be utilised and by means of which, even in the rearward tilted end position, a comfortable reversal of the rocking motion can be effected.

According to the invention this is achieved by at least one tension or compression spring which is operative in the rearward pivoted end position of the back-rest, which acts as a buffer and which, in the rearward pivoted end position, abuts against an abutment part of the seat, of the back-rest and/or of the gas compression spring, which abutment part is displaceable or pivotable during the tilting procedure.

As a result of this measure according to the invention, on the one hand, it is made possible for the rocking motion to be carried out comfortably only against the force of one gas compression spring, so that an easy but effective rocking movement is possible. On the other hand, the rocking motion is reversed in the rearward end range, in which case according to the intensity of the rocking movement this tension or compression spring is loaded to a greater or lesser extent.

However, this compression to a greater or lesser extent causes additionally, precisely in this rearward displaced end position of the back-rest, a repulsion in the direction of the front rest position of the back-rest, so that precisely during a rocking movement this range is bridged, which range as a result of the varied leverages can be controlled only to a reduced extent by the gas compression spring. In practice, during a rocking movement, the action of the gas compression spring is followed directly by the action of the tension or compression spring acting as buffer, in which case only thereby is a possibility offered of carrying out comfortable rocking over the entire tilting range of the back-rest.

Further features of the invention and particular advantages will be explained in more detail in the following description on the basis of some examples of embodiment.

Figure 1 shows a top view of a portion of a seat carrier, wherein for the sake of clarity the seat itself is omitted; Figures 2 and 3 each show sections along the line I-I in Figure 1, both these Figures showing the two end positions of the tilting position of the back-rest; Figures 4 and 5 show two further examples of embodiment with a spring acting as buffer, in each of which the seat carrier is illustrated in vertical section, namely in that zone designated Il-Il in Figure 6; Figures 6 to 11 show another example of embodiment of the invention, wherein Figure 6 again illustrates a top view of the seat carrier;Figure 7 shows a section along the line Il-Il; Figures 8 to 10 show sections along the line Ill-Ill in different positions of the spring acting as buffer, and Figure 11 shows an illustration, enlarged with respect to Figures 8 to 10, of a spring acting as a buffer.

As already stated, in the illustrated seat the seat surface, the back-rest and the pedestal have been omitted for the sake of clarity. A tube 1 is attached to the pedestal and is provided with a gas spring and additionally, if necessary, with a helical compression spring. Vertical adjustment of the seat can be effected by means of a corresponding hand lever 2 and a lever 3 acting on a valve of the gas compression spring. The seat carrier 4 is securely connected to the top end of the tube 1. The back-rest 5 then adjoins this seat carrier 4, these two parts being pivotably interconnected via the pivot 6.

At a distance from the pivot 6 the rear support member 8 for the seat surface is pivotably mounted about a pivot 7. The front support member 9 is securely connected to the seat carrier 4, in which case the fastening of the seat surface to this support member 9 can be effected via a hinge or a resilient part. During tilting of the backrest 5 about the pivot 6, the rear support member 8 is correspondingly raised or lowered so that, depending on the position of the back-rest 5, the seat surface can also be adjusted.

To achieve a simple adjustment possibility for the back-rest and seat surface, a gas compression spring 10 is provided. This gas compression spring 10 is pivotable about the front pivot 12. The rearward end of this gas compression spring 10 engages on a pin 1 3 which likewise constitutes a pivot 14. This pin 13 is also engaged by a thrust lever 1 5 whose other end is held pivotably on the back-rest 5. Advantageously, this thrust lever 1 5 engages on the same pivot 7 as the rear support member 8 for the seat surface. In any case, this pivot 7 must be at a distance from the pivot 6 between the back-rest 5 and the seat carrier 4.

Furthermore, a lever arm 1 6 is provided which, at one end, is pivotable about the pivot 1 7 on the fixed seat carrier 4 and, at the other end, engages on the pin 1 3 at the pivot 14. Therefore, when the back-rest 5 is tilted accordingly, the pivot 14 moves in an arc about the pivot 17, in which case as a result thereof already a small movement of the back-rest 5 causes a correspondingly enlarged movement of the gas compression spring 10. It is thus evident that, with structurally very simple means, a conversion of the displacement travel of the gas compression spring 10 is achieved.

According to the present invention, a tension or compression spring acting as a buffer is provided, which is operative in the rearward pivoted end position of the back-rest 5. This tension or compression spring acting as a buffer abuts, in the rearward pivoted end position of the back-rest, against an abutment part of the seat, of the backrest 5 and/or of the gas spring 1 0, this abutment part being displaceable or pivotable during the tilting procedure.

One possible embodiment is evident from Figures 1 to 3. In this development, the spring acting as a buffer takes the form of a bending spring 30, that is preferably in the form of a leaf spring. According to requirements, this spring may be of corresponding design. It is essential here that in the forward tilted end position of the backrest (Figure 3) this bending spring 30 is at a distance from the associated abutment part, which corresponds approximately to two thirds of the entire displacement or tilting range of this abutment part. In this embodiment, there acts as abutment part the free end of the lever arm 1 6 nearest the pin 1 3, which during tilting of the back-rest 5 is moved in a specific circular sector.

The bending spring 30 extends into the tilting range of this arm 1 6, in which case the bending spring 30 abuts against this lever arm 1 6 only in the last third of the tilting range. This embodiment is particularly simple in its structural design, since such a bending spring 30 can be fastened to a corresponding transverse web 31 of the seat carrier 4, for example by means of a screw or the like. The freely projecting part of the bending spring 30 then extends into the tilting range of the lever 16.

Two further embodiments of the invention are evident from Figures 4 and 5. Here helical springs 33 and 34 respectively are provided as buffers, which are mounted on the piston 35 and piston cylinder 36 respectively of the gas spring 10.

In these embodiments too there is again provision for a displacement movement of the back-rest 5 to be possible over only about two thirds of the tilting range against the force of the gas spring 10. The spring 33 or 34 acting as a buffer thus comes into use only in the last section, namely in the rearward pivoted end position of the back-rest. In such a development it is necessary to provide corresponding discs 37 and 38 respectively, which then act as abutment part of the free end range of the springs 33 and 34 respectively. In the development according to Figure 4, the other end of the spring 33 abuts against the end zone of the piston cylinder 36. In the development according to Figure 5, one end of the spring 34 abuts against a locking or locating ring 39.

Of course, it is possible within the scope of the invention for two such gas compression springs 10 to be connected parallel to one another, in which case either one of these gas compression springs is designed in accordance with the embodiment of Figures 4 and 5, or else both gas compression springs can then be associated with such springs 33 and 34 acting as a buffer. In this connection, it is also possible to incorporate a corresponding spring, acting as buffer, in the gas cylinder, i.e. to arrange it in the interior of the piston cylinder 36.

In the development according to Figures 6 to 11, the spring acting as a buffer takes the form of a helical spring 40, in which case such an arrangement can be provided, of course, in structurally simple manner at different locations of the seat carrier 4. It is evident from Figure 6 that, in a structural variant of embodiment, this helical spring 40 is disposed parallel to the gas compression spring 10. This helical spring 40 is mounted on a rod 41 coaxiallytherewith, in which case this rod engages at one end on a pivotable part of the seat carrier. Advantageously, this rod engages on the pin 13. At its other end, this rod 41 is retained displaceably in a guide sleeve 42, this guide sleeve 42 being supported on a pin 1 2 in the seat carrier 4.This guide sleeve 42 is also designed as a non-disclaceable ahiltmRnt r > rt frbr the helical spring 40, in which case for achieving accurate adjustment one or more abutment shims 43 can be fitted on this guide sleeve. Figures 8 and 11 illustrate the rest position of the back-rest and thus also the rest position of the helical spring 40. It is evident therefrom that in this rest position of the back-rest 5 the distance T of one end of the spring from the abutment face 44 of the abutment part corresponds to approximately two thirds of the entire displacement travel G of the rod 41 and thus also of the tilting range of the lever arm 1 6.

Therefore, over the majority of the range of the tilting movement, the gas compression spring 10 alone takes up the necessary force so that only in the rearward tilted end range of the back-rest does the helical spring 40 intervene as a buffer.

Figure 9 shows precisely the position in which the helical spring 40 is applied against the abutment face 44 and Figure 10 illustrates the rearward tilted end position.

Figure 11 illustrates in a partial section how a resilient sleeve 45 is inserted between the rod 41 and the helical spring 40 lying coaxial therewith, this sleeve 45 extending at least over a part of the length of the spring 40 in the relaxed condition.

Although in the illustrated example of embodiment this sleeve 45 has the same length as the spring 40 in the relaxed condition, an additional buffer action results since this sleeve 45 can be compressed correspondingly. Moreover, this sleeve 45 has of course the purpose of keeping the helical spring 40 acting as buffer in an exactly coaxial position relative to the rod 41.

Therefore, it is also possible for only a short portion of such a sleeve 45 to be inserted or else several such portions which are shorter than the length of the helical spring 40 in the relaxed condition.

Therefore, in the present invention the essentiai feature is that a buffer element is provided precisely in the rearward tilted end range of the back-rest. Some possible variants of embodiment have been illustrated in the drawings and explained in the description. Of course, by correspond structural measures it is also possible to provide a tension spring instead of a compression spring, in which case, of course, the bending spring could also be loaded in a different direction from that shown in Figures 1 to 3. It is also possible, for example, to provide torsion springs or also other spring types. It is only necessary that in any-configuration there is provided a tension or compression spring acting as a buffer.

Claims

1. A seat with a seat surface and a back-rest, in which at least one support member of the seat surface and the back-rest are adjustable in dependence upon one another in relation to a seat carrier connected to a pedestal and are respectively pivotable about an approximately horizontal axis, and a gas compression spring is provided for the return movement and for optional positional location, which gas compression spring is in operative connection at one end with the seat carrier and at the other end with the back-rest, while at its end on the back-rest side the gas compression spring is pivotably secured to a push lever engaging on the back-rest, wherein at least one tension or compression spring which is operative in the rearward pivoted end position of the back-rest, which acts as a buffer and which, in the rearward pivoted end position, abuts against an abutment part of the seat, of the back-rest and/or of the gas compression spring, this abutment part being displaceable or pivotable during the tilting procedure.

2. A seat as claimed in Claim 1, wherein the spring acting as a buffer, in the forward-tilted end position of the back-rest, has a one end, respectively at its resilient end, a distance from the associated abutment part, which corresponds approximately to two thirds of the total displacement range of the abutment part.

3. A seat as claimed in Claim 1 or Claim 2, wherein the spring acting as a buffer takes the form of a bending spring, preferably in the form of a leaf spring, whose freely projecting end engages in the tilting range of a push lever, arranged on the back-rest or of a return-lever arm between the push lever and the seat carrier.

4. A seat as claimed in Claim 1 or Claim 2 wherein the spring acting as a buffer takes the form of a helical spring mounted respectively on the piston and piston cylinder of the gas spring.

5. A seat as claimed in Claim 1 or Claim 2 wherein the spring acting as a buffer takes the form of a helical spring mounted coaxially on a displaceable rod engaging on a pivotable lever arm, one end of the rod being held displaceably in a guide sleeve and the non-displaceable guide sleeve being designed as an abutment part for the spring, in which case in the rest position of the back-rest the said distance of one spring end from the abutment part corresponds to approximately two thirds of the said total displacement travel of the rod.

6. A seat as claimed in Claim 5, wherein a resilient sleeve is inserted between the rod and the helical spring lying coaxial therewith, which sleeve extends at least over a part of the length of the helical spring in the relaxed condition.

7. A seat substantially as hereinbefore described with reference to and as shown in Figures 1 to 3, or in Figure 4, or in Figure 5, or in Figures 6-11 1 of the accompanying drawings.