Seat Construction

Abstract

An upper support is upwardly spaced above a lower support and connected with the latter so as to be moveable downwardly toward and away from the lower support. A hollow elongated elastomeric spring is arranged below and in engagement with the upper support, with its longitudinal axis in upward position so that the spring is elastically compressible in direction of its longitudinal axis when the upper support moves in direction towards the lower support.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to seat constructions, and more particularly to vehicle seats.

The seats in many vehicles, particularly automotive vehicles but also others, are provided with spring arrangements to increase the comfort of a user. Many constructions for this purpose are already known. It is frequently necessary in such seats that the overall height be quite low, and this eliminates many spring arrangements which could otherwise be used.

One type of spring arrangement which has been used in seats where their height is supposed to be low is a construction where an upper and a lower seat support are provided, being connected by pairs of crossed levers which are pivotably connected with their intersection and which each have one end which is rigidly connected with one of its supports and another end freely slideably connected with the other of the seat supports. A system of tension springs is incorporated in the seat back and connected in suitable manner with the levers so as to tend to elastically urge the same to a position in which the upper support is raised to its maximum spacing upwardly from the lower support.

This construction has the disadvantage, however, that if the angle of inclination of the seat back is changed, a change in the tension exerted by the tension springs will necessarily result. The more pronounced the inclination of the seat back in rearward direction -- that is away from the actual supporting seat -- becomes, the less will be the tensile force exerted by the springs. In addition this construction is necessarily relatively complicated and, a further disadvantage, limits -- for the above reasons -- the extent to which the seat back can be inclined.

SUMMARY OF THE INVENTION

It is, accordingly, an object of the present invention to overcome the above mentioned disadvantages.

More particularly, it is an object of the present invention to provide an improved seat construction wherein the spring arrangement is very simple, permits the overall height of the seat construction to be low, and does not in any way influence the adjustability of the seat back.

In pursuance of the above objects, and of others which will become apparent hereafter, one feature of the invention resides, briefly stated, in a seat having a lower support and an upper support upwardly spaced from the lower support. Connecting means connect the supports with freedom of displacement of the upper support towards and away from the lower support.

According to the invention, I further provide hollow, elongated elastomeric spring means having an upright longitudinal axis and being arranged below the upper support, the spring means being elastomerically compressible by engagement with the upper support in direction of its longitudinal axis in response to displacement of the upper support towards the lower support.

Hollow elongated elastomeric springs in themselves are not new. However, the use of such a spring in a seat construction of the type under discussion brings with it decided advantages not obtainable with the spring constructions which heretofore were considered to be necessary in such seats. Hollow elongated springs of elastomeric material, such as rubber or synthetic plastic, can be relatively short but have an extremely long compression stroke -- and of course return or relaxation stroke -- by comparison to their length. For this reason, such springs are particularly advantageous in the construction according to the present invention where it is desired that the overall height of the seat be low.

According to the invention it is advantageous that the spring engage the connecting means, and more particularly, pairs of crossed levers which are arranged in scissor shape as outlined earlier, and the combination of such a spring with the engagement thereof on the crossed levers, and more particularly in the region of the pivot points, where the levers intersect one another, assures that the deflection stroke of the spring corresponds to half the distance of movement of the upper support with reference to the lower support. It is known that springs of the type under discussion can be compressed at most to approximately half the amount of their unstressed length, so that in the construction according to the present invention, the length of the spring in its untensioned state corresponds approximately to the distance through which the upper support can move with reference to the lower support. The result is not only a very simple construction but an extremely low height requirement for the seat.

A further advantage of springs of the type under discussion that they have a relatively great inherent damping factor which can be used to advantage. By arranging the spring in upright position, that is with its longitudinal axis upright, a linear deflection stroke is obtained. Thus, the spring will not perform arcuate movements at all during compression and relaxation and I obtain a constant spring action throughout the entire stroke length. If desired, I can construct the spring in such a manner that in the terminal portion of the movement of the upper support with reference to the lower support the spring characteristic can be progressive.

According to a further advantageous concept of the invention, a damping device or dashpot -- which corresponds to those conventionally used with seat constructions of the general type under discussion (Belgian Pat. No. 495,281) -- is arranged horizontally or near horizontally in the region of the lower support and has one end pivotably connected to and below the lower abutment for the spring whereas its other end is pivotably connected on one of the freely moveable ends of the crossed levers. Arrangement of the dashpot in this manner also contributes to making the overall height of the seat construction low.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a seat according to one embodiment of the invention, partly in section and partly broken away;

FIG. 1a is a view of one side of the seat shown in FIG. 1

FIG. 2 is a section on line II -- II of FIG. 1; and

FIG. 3 is a fragmentary sectional elevation illustrating a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Discussing firstly the embodiments illustrated in FIGS. 1, 1a and 2, it will be seen that an upper support in form of a frame is provided composed of two transversely spaced U-shaped members 1 which are connected at their front and rear ends by transverse members 2, 2a. This upper support carries the non-illustrated actual seat, that is the upholstery, cover material, etc.

Downwardly spaced from the upper support is a lower support, again frame-shaped and also consisting of two transversely spaced members 3 of substantially U-shaped cross-section, connected at their opposite ends by transverse members 4, 4a.

At two opposite sides of the upper and lower supports, the same, that is the upper and lower supports, are connected by connecting means in form of pairs of crossed levers 5,6 which intersect one another in scissors form and at the point of intersection are pivotably connected by threaded pivot pins 8 (see FIGS. 1 and 2). One end of each of the levers 5, 6 is fast with the respective upper and lower support and the opposite ends are pivotably and slidably connected with the respective upper and lower supports by means of rollers 7 carried on these opposite ends and guided in the members 1, 3 respectively. This is shown in FIG. 2. The levers 5 of each pair, and also the levers 6 of each pair, are connected by transverse rods or analogous members 9 (see FIG. 2 where only one pair of levers 5,6 is visible).

In accordance with the invention I provide an upright, hollow elongated elastomeric spring 10 which may consist of rubber or synthetic plastic material and which contacts the upper support by engagement in the region of the point of intersection of the levers 5,6 of each pair. The upper end of the spring 10 abuts against an engagement plate 11 which is of inverted U-shape and whose lateral arms 12 extend downwardly and are pivotably connected to the pivot pins 8 -- for instance by being provided with holes through which the pivot pins 8 extend (as shown in FIG. 1). The lower end of the spring 10 abuts against a support plate 13 whose lateral portions are also slightly downwardly offset and identified with reference numeral 14; these lateral portions 14 are connected to the lower legs of the members 3 of U-shaped cross-section.

When the upper support moves downwardly towards the lower support, the spring 10 is pressed by plate 11 against the plate 13, and is simultaneously radially outwardly deflected as it is axially compressed. Guide pins 15 are provided on the plates 11 and 13 and extend from above and from below into the hollow interior of the spring 10 (see FIG. 1) so as to guide the spring against lateral displacement other than radially outward distention.

By having the spring 10 connected via plate 11 with the pins 8, that is the point of intersection of the levers 5,6 of each pair, the stroke of the spring 10 corresponds to only half the displacement distance between the upper and lower seats so that the total height or length of the spring 10 is unstressed condition need correspond only to the distance of displacement between the upper and lower supports, taking into account that the maximum axial compression of a spring corresponding to the spring 10 should only be approximately one-half of the total height or length of the spring in unstressed condition.

It is clear from FIGS. 1 and 2 that the spring 10 has a linear stroke so that a constant spring effect is obtained which can be made progressive towards the end of the compression stroke by correspondingly configurating the spring 10 in known manner, if desired.

FIG. 2 shows particularly clearly a conventional dashpot 16 which is known in such seat constructions and whose construction itself is not a part of the invention. According to one concept of the invention, however, dashpot 16 is arranged horizontally or substantially horizontally as shown in FIG. 2, below the supporting plate 13 for the spring 10, with one end of the dashpot 16 being connected below the supporting plate 13 where it is pivotably secured for pivoting movement about the axis 18; the lower side of the plate 13 is provided for this purpose with a downward projection 17, for instance a bifurcated projection. The opposite end of the dashpot 16 is pivotably connected with the lowermost of the transverse connectors 9, for instance by means of two levers 20 which are turnably mounted on the transverse connector 9 and to which the opposite end of the dashpot 16 is in turn pivotably secured by the pin or shaft 19. This construction has the advantage of facilitating the construction of the seat in such a manner that it need have only a very low height as seen in direction intermediate the top and bottom of FIG. 2, for instance.

Coming to the embodiment illustrated in FIG. 3 it will be seen that this illustrates a possibility for adjusting the effects of the spring. The lower supporting plate is here identified with reference numeral 13a and formed with an internally tapped bore through which the externally threaded guide pin 15a is threaded. A knurled or otherwise configurated knob 21 is provided on pin 15a so that it can be threaded deeper or less deep into the bore in the plate 13a. The portion of the guide pin 15a which extends upwardly through the plate 13a is provided with a circumferential groove 22 -- for instance by making the upper end of the guide pin 15a separable from the remainder of the guide pin 15a and securing it threadedly or in another manner to this remainder with the groove 22 being defined between the two sections thus obtained. Seated in the groove 22 is an inner circumferential marginal portion of an annular disc member 22 on which the lower end of the spring 10 is seated. When the guide pin 15a is threaded through the plate 13a in the sense displacing the guide pin 15a upwardly with reference to the plate 13a, the disc member 23 in turn is moved upwardly and thereby tends to axially compress the spring 10. Conversely, removal of the guide pin 15a in downward direction, tends to relax the spring 10 if the same has previously been stressed.

In the embodiment of FIG. 3 the bifurcated downwardly extending projection 17 for connection of the dashpot 16 is arranged forwardly of the guide pin 15a as seen from the direction of the transverse connector 9 to which the opposite end of the dashpot 16 is to be connected. Thus, interference with the knurled knob 21, and freedom of access to the latter, is avoided.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a seat construction, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

Claims

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims;

1. In a seat, particularly a vehicle seat, in combination, a lower support; an upper support upwardly spaced from said lower support; connecting means comprising at least two pairs of crossed levers connecting said supports with freedom of displacement of said upper support towards and away from said lower support, the levers each having an end connected to said upper and one end connected to said lower support, and pivot means connecting the levers of each pair at their intersection; hollow elongated elastomeric spring means having an upright longitudinal axis acting with one end on said lower support and with the other end on said pairs of levers at the respective pivot means, said elastomeric spring means being compressible in a direction from said upper support towards said lower support.

2. In a seat as defined in claim 1, wherein said spring means consists at least predominantly of rubber.

3. In a seat as defined in claim 1, wherein said spring means consists at least predominantly of synthetic plastic material.

4. In a seat as defined in claim 1; further comprising an engaging element having substantially the shape of an inverted U and including two lateral arm portions mounted respectively on said pivot means of said two pairs of crossed levers, and a center portion engaging the upper end of said elastomeric spring means.

5. In a seat as defined in claim 1; further comprising a plate element carried by said lower support and having an upper side; and wherein said elastomeric spring is seated upon and has a lower end abuttingly engaging said upper side of said plate element.

6. In a seat as defined in claim 5, said levers each having an other end; further comprising at least one transverse connector connecting said other ends of said levers of said pairs; and a dashpot having one end pivotally connected to and below said plate element and an other end pivotally connected to said transverse connector.

7. In a seat as defined in claim 4; further comprising a plate element carried by said lower support and having an upper side; and wherein said elastomeric spring is seated upon and has a lower end abuttingly engaging said upper side of said plate element.

8. In a seat as defined in claim 7; further comprising guide pin means provided on at least one of said elements and extending into said tubular elastomeric spring means.

9. In a seat as defined in claim 7; further comprising guide pin means provided on both of said elements and extending into said tubular elastomeric spring means.

10. In a seat as defined in claim 9; further comprising a disk member on said lower pin below said lower end; and wherein the guide pin means on said plate element is fast with said disk member and displaceable with the latter upwardly away from and downwardly toward said lower side.

11. In a seat as defined in claim 7, said plate element comprising a middle portion and a pair of lateral securing portions, and said spring means having in unstressed condition a predetermined maximum outer diameter; and wherein the outer dimensions of said center and middle portions approximate said maximum outer diameter.