NL8300928A - Public transport bus seat - has leaf spring suspension and resilient pivot point for seat on frame - Google Patents

Abstract

The seat (1) is supported on the frame (2) by leaf springs (3,4). The ends of the leaf springs (5,6) are connected to the seat frame and the centre parts (7,8) with the seat dish. Alternatively, the suspension for the leaf spring (3) may be a resilient pivot (10) with a rotating point (11) under the seat at approx. floor level (12). The resilient pivots form an angle of between 20 and 70 degrees to the vertical.

Description

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Emsta B.V. Breda Vehicle seat

The invention relates to a vehicle seat, particularly intended for buses.

5 Such seats are widely used in vehicles usually intended for public transport.

The usual version of a vehicle seat or bus seat is a metal frame with legs screwed to the floor, whereby an approximately horizontal frame part forms the support for a seat cushion 10 with a possible stiff back. The seat cushion is foam rubber, polyurethane foam, possibly a steel spring construction covered with elastic plastic cloth. The backrest is similar.

The functions of and the various requirements that can be imposed on the vehicle seat are: 15 - Providing a seat of sufficient rigidity and strength to protect the passenger from injury due to hard parts and (deformation) of the vehicle, even in (light) collisions. chair. The strength of the seat frame in order to comply with the safety standards 74/408 / EEC exceeds the 20 requirements arising from the vibration load and the speed changes when driving.

- The upholstery or finish of the seat cushion and backrest must keep the passenger sufficiently "retained" when longitudinal and transverse forces of a quasi-static nature occur as a result of acceleration, braking and cornering. the surface roughness of the seat and backrest must be such that accelerations of 5m / sec2 in the longitudinal and transverse directions can be absorbed without any significant displacement of the passenger relative to the seat.

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The use in a road vehicle (with seats arranged in the direction of travel) requires that the passenger seated on the seat is able to spring vertically and transversely about a longitudinal axis, and that both longitudinal movements and immersion movements are strongly limited in the direction of travel. The seat must also be

the support cannot rotate on a vertical axis. This also results from forces that occur as a result of brakes and (light) collisions.

- The seat cushion, due to its elasticity and damping properties, 10 must protect the passenger from the nuisance of vibrations that occur while driving in the vehicle. Vibration shielding consists of reducing the displacement of the passenger on the seat compared to that of the vehicle floor due to vibrations generated by the engine and wheels when driving over uneven surfaces. Natural frequencies of the walls and floor of the vehicle can sometimes cause unpleasant frequencies locally.

The usual chairs are prone to damage. The object of the invention is a bus seat, which protects the passenger in an effective manner against the vibrations that occur and which cannot yet be easily damaged.

To this end it is proposed according to the invention that the chair is formed from a hard bend-resistant seat shell, which is vertical, transverse and rotational relative to an axis under the seat of the chair approximately at floor level parallel to the longitudinal axis of the bus. sprung on a frame.

It has been found that such a resilient support of a hard seat shell nevertheless provides the desired comfort for a passenger. Optionally, the seat shell may be covered with a thin compliant upholstery, which is easily interchangeable.

It is noted that a spring seat is known from Dutch patent 13537, wherein the seat part rests on one or more air balls. -------------------------------- —----------------- ------------------------------------- ------------- ---- 014Q22LC 8 3 0 ö 9 2 8 -3-

No solution has been given to the problem of damage, while this suspension seat is provided with vertical suspension only, so that the vibration isolation in other directions and the passenger comfort, as well as safety in the event of collision, are insufficiently guaranteed.

Further details of the invention will become apparent from the following description of some embodiments, with reference to the drawing.

In the drawing shows.

Fig. 1. a skewed projection of an embodiment with transverse leaf springs under the seat and behind the back part of the seat shell; • f

Fig 2. the operation of a transverse leaf spring with a rigid transverse element, attached to the back part of the seat shell;

Fig. 3. the suspension with a transversely placed leaf spring under the seat of the seat shell hanging by means of spring swings on the frame;

Fig 4. the suspension of a seat shell with a central spring under the seat and guide arms connected by a torsion coupling;

Fig. 5. a slotted hole guide for the back of a seat shell; Fig. 6. the embodiment of the suspension of a seat shell according to Fig. 4 in oblique projection;

Fig. 7. an embodiment of the suspension of the seat with angled leaf spring elements;

Fig. 8. an embodiment of the leaf spring elements of figure 7; * ...... 83 0 0 9 2 8 -4- V +

Fig. 9. seat shell with a passenger weight compensating air spring between the seat and the frame;

Fig 10. seat shell with between the seat and the frame the passenger-5 weight compensating air bag; and

Fig. 11. seat shell with between the seat and the frame the passenger weight compensating annular air bag.

Figure 1 shows the springing of the seat shell 1 on the frame 2 by means of the leaf springs 3, 4. The leaf springs 3, 4 are connected with the ends 5,6 10 to the frame 2 and the centers 7,8 are connected to the seat shell 1. In figure 2 it can be seen that the center of the leaf spring 4 by means of a bend-stiff transverse element 9 is attached to the seat shell 1. The ends 5, 6, with which the leaf springs 3, 4 are connected to the frame 2, are provided with an elastic bearing. In figure 3, by suspending the leaf spring 3 on spring swings 10, 15 is indicated in another way to get to the point of rotation 11 under the seat of the seat shell with passenger, namely to approximately floor height 12. The spring swings 10 make an angle between 20 and 70 °, with the vertical. Figures 4 and 6 show a variant suspension of the seat shell 1 on the frame 2 20, connected by a central spring 13 and guide arms 14 mutually connected by a torsion coupling rod 15.

It can be seen in figure 5 that the backrest of the seat shell 1 is provided with a guide with slotted holes to enable vertical movement of the seat shell.

Figure 7 shows another variant of the suspension of the seat shell 1 on the frame 2 by means of two spring elements 17 arranged with the long axis in the direction of travel. These spring elements 17 make an angle with the vertical axis between 20 and 70 °, so that a rotation point 11 under the

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8300928 ♦ V '-5- seat of the seat shell with passenger at about floor level 12.

The spring elements 17 are shown in longitudinal direction in figure 8.

The spring element 17 consists of two spring blades 18 with a spacer 19 between them. By choosing the torsion of the spring blades 18 and a suitable height of the spacer 19, the desired lateral flexibility of the spring elements 17 is created. with incidental impacts due to ridges in the road surface in addition to the isolation of more or less continuous vibrations of a certain amplitude, usually of a few mm. For the incidental impacts, the spring elements must have a progressive characteristic of the shape F * -C.x n .: e spring in which: F = spring force C = constant x = spring compression from zero position 15 n = exponent

With such a more or less exponentially extending spring characteristic, the vibration isolation for passengers with light or heavy weight is quite different. In addition, the seat of the seat shell 1 in a loaded condition has a lower height relative to the floor 12. These 20 drawbacks can be met by applying, as shown in figure 9, a gas spring 20, under the seat of the seat shell 1 The passenger's weight can then be offset. This compensation can also take place, as indicated in figure 10 with an air bag 21, or as shown in figure 11 with an annular air bag 22.

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Claims (15)

Vehicle seat, in particular for buses, characterized in that the seat consists of a rigid bending-resistant seat shell, which, in vertical, transverse and rotational direction, relative to an axis under the seat of the seat, is approximately 5 floor height parallel to the longitudinal axis of the bus, is suspended on a frame. Vehicle seat according to claim 1, characterized in that the suspension, arranged under the seat and behind the back of the seat shell, is substantially rigid in the direction of travel. Vehicle seat according to claim 1, characterized in that the suspension under the front of the seat consists of a transversely positioned leaf spring with an elastic bearing, the ends of the leaf spring being connected to the frame via a bearing and the center of the leaf spring is connected to the seat shell, and the suspension of the back part of the seat shell also consists of a transverse leaf spring, the ends of which with the frame and the middle part of the leaf spring are provided with a bending-rigid transverse element with at the end thereof a bearing, which is connected to the back part of the seat shell. Vehicle seat according to claim 3, characterized in that the elastic bearing of the leaf springs consists of rubber parts pressed into the eyes. Vehicle seat according to claim 3, characterized in that the leaf spring is fixed to the frame under the front of the seat shell seat by means of 25 spring swings, the spring swings converging downwards. Vehicle seat according to claim 5, characterized in that the spring swings in the rest position run at an angle to the vertical axis, lying between 20 ° and 70 °. 8300928 .1 -1- Vehicle seat according to claim 1, characterized in that under the seat of the seat shell, directionally guided arms are provided, which are hinged at one end to the frame and hinged at the other end to the seat of the seat. seat shell, in which the guided amen is provided with a torsion coupling bar near the attachment to the seat of the seat shell, and that a vertical spring is arranged under the front of the seat and that a pin is arranged behind the back part of the seat shell which is vertically movable in a slotted hole-shaped guide. i Vehicle seat according to claim 1, characterized in that near the side edges of the seat of the seat shell, two spring elements placed in the direction of travel, built up of two spring blades with a spacer between them, are arranged, these elements converging downwards. Vehicle seat according to claim 8, characterized in that the spring elements enclose an angle β with the vertical axis, lying between 20 and 70 °. Vehicle seat according to any one of the preceding claims, characterized in that the spring elements have a progressive characteristic of the shape F = -C.x11. feather Vehicle seat according to one of the preceding claims, characterized in that the vertical suspension and the transverse suspension are chosen such that the isolation of the vibration frequency is between 3 and 20 Hz. Vehicle seat according to claims 3,5,7 and 8, characterized in that a gas spring is arranged under the front of the seat. 83 0 0 9 2 8 -8- Vehicle seat according to Claims 3,5,7,8, characterized in that the progressive suspension is combined with an air bag arranged between the seat and the frame, the pressure of which is adjustable. Vehicle seat according to claim 13, characterized in that the air pocket 5 between the seat and the frame is annular. Vehicle seat according to one of the preceding claims, characterized in that an adjustment machine is arranged between the seat shells and the suspension system in order to obtain height-adjustable seat shells. . I 8300928 Ü4IJ22LC