IE42963B1 - Articulation for vehicle seat comprising a ball mounted reducing element - Google Patents

Description

Articulations for vehicle seats are already known, and particularly articulations for hotor-car seats having a component sequred to the frame of the seating, while another component is secured to the frame of the seat-back.

Every seat generally comprises two articulations, i.e. one being manually controlled, and the second one, linked to the first one by a linking part so as to be operated synchronously with the first one.

The mechanism of such articulations may include, in a □ manner known per se, a reducing gear train thus ensuring a suitable setting of the back for every user, the corresponding position being obtained very accurately as the reducing gear train enables a fine adjustment of the position of the seat-back relative to the seating.

However, these articulations have a disadvantage as they become locked under influence of some stresses, due to. their own design, which has however for its advantage to prevent these articulations, fitted with a reducing gear train, from being reversible, i.e. prevents the seat-back to be inadvertently offset backwardly.

Since the seat articulations may be locked under some rather peculiar inst.mces of use, it appeared that this disadvantage must be absolutely overcome for safety reasons.

The present invention may solve this problem, in particular, by providing an articulation provided with all the advantages of the known articulations, but which, further, cannot in any case become definitely locked, while also preventing any risk of inadvertent reversible motion.

Moreover, the operation of the device should be very smooth, which enables a very accurate adjustment.

According to the invention there is provided a vehicle seat comprising an articulation between the seating and the back frame of the vehicle seat, the articulation comprising a stationery cheek fixed to the seating and so shaped to have an inner set of teeth coacting with one set of teeth of a double slave gear mounted on a cam fixed to a shaft rotatably mounted ana used as a central axis for the articulation, a second cheek fixed to the back frame and having an inner toothed ring coacting with the second set of teeth of the above mentioned double slave gear, so to obtain through a rotating motion of the slave gear driven by the cam and shaft, a smooth continuous motion of the cheek fixed to the back frame, characterized in that balls are inserted on one hand between the cam and the slave gear and on the other hand between the cam and the stationery cheek.

According to another preferred feature of the invention a ball race is inserted between the balls and the slave gear in order to hold the balls and tighten correctly the parts together.

An embodiment of this invention is shown, by way of example, in the accompanying drawings.

Fig. 1 is a partly sectional elevation view of a set of articulations required to fit a seat.

Fig. 2 is a side elevation view of the articulation provided with the control means, this elevation view being taken from the control side.

Fig. 3 is a side elevation view of the articulation from the without-control side, taken from the outer face of the seat.

Fig, 4 is an internal elevation view of the cheek secured onto the frame of the seat back S2963 Fig. 5 is a lateral inner elevation view of the cheek secured to the seating frame of the seat. .

Fig. 6 is an enlarged sectional elevation of a modification of the articulation.

Fig.' 7 is an enlarged partial sectional view of another modification of the articulation.

Fig. 8 is an enlarged partial sectional view of a slight modification of the mechanism of the articulation of Fig. 1.

Referring now to the drawings, Fig. 1 shows an articulation comprising a cheek 1 provided with holes 2 (see Fig. 3) intended to link the cheek with a seat-back frame.

The lower portion la of the cheek which is almost circular, has two recesses 3, 4, coaxial with a hole 5 used for passage of a hollow shaft 6 having a portion 6a receiving a shaft 7 having a- square cross-section, while a portion 6b is bored with a hole 8 for securing the operating means of the articulation which is most often, a button which is knurled or roughened for facilitating grasping thereof.

A cam 9, secured to the shaft 6 (see Fig, 2) is eccentrically mounted relative to the shaft 6. The cam 9 has a central offset part 9a located in the recess 4 of the cheek 1. It will be noted that this part 9a of the cam is separated by balls 10 from the lower portion of the recess 4 whereby the balls 10 are disposed between the cam 9 and the cheek 1. The other portion 9 of the cam is located in the recess 3 of cheek 1 and has a peripheral circular groove 9b in which balls 11 are located whereby the balls 11 are disposed between the cam 9 and a stationary^: cheek 16.

On the cam 9, and fully encircling it, there is mounted with the balls 11 disposed therebetween a slave gear 12 having two coaxial sets of teeth 12a and 12b; the number of the teeth of the set 12a being related with the number of the teeth 13 provided in the peripheral flange of the recess 3 of the cheek 1, this set of teeth 12a coacting with the teeth 13.

The number of teeth of the set 12b is related with the number of coacting teeth 15; these teeth 15 being provided on the cheek 16 (Fig. 5) which is secured to the frame of the seating through holes 17. It will be noted that the longitudinal axis of the cheek 16 makes an angle of 45° with respect to horizontal.

Owing to the eccentric mounting of the slave gear, only the teeth of the upper part 7 of the gear 12 mounted on the cam 9 contact the teeth 13 and 15 of the cheeks 1 and 16 (Figure 2).

As best seen in Fig. 1, the cheek 16 is machine shaped in such a way as to be provided in its central part with a recess 16a in which the slave gear 12 and cam 9 are partially located. Reference 18 shows the central hole providing passage for the central hollow shaft 6. - The movable cheek 1, secured to the seat-back, and the stationary cheek 16, secured to the seating are linked together through holding means, as best seen at 20 in Figs. 1, 2 and 3.

From the above described mounting, it obviously appears that the linking by the rod 7 with the second articulation, shown at the left of Fig. 1, enables a simultaneous operation in a simple way of the two above referred articulations, by means of the control means secured on the shaft 6 (operating button).

As it can be understood from the guiding of the cheek 1, comprising a circular groove 21 by a flange 22 secured to the stationery cheek 16, this flange Imay easily and slowly rotate via the shaft 6 which drives the cam 9, making then the slave gear 12. to rotate, the set of teeth 12a of which coacting with the teeth 13 of the cheek 1 causes the cheek 1 to rotate towards the right or left direction (Pigs. 2 or 3).

The balls 10, 11 enable the components to smoothly slide the one relative to the other but the tight fit of each articulation and, in particular, the friction of the flange 22 in the groove 25 ensures a sufficient grip preventing the articulations to be accidentally reversed. There is actually no reversibility of :he articulation in case of a shock. It is however possible :o pivot the seat back by acting on the operating means of the irticulation. In case of a shock such a pivotal movement is >revented, the articulation can only break. It is actually tecessary, in order to make a pivotal movement possible, that it least one of the cheeks be driven. In ho case can the seat ack drive the cheeks.

Moreover, the tight fitting of the balls automatically akes up the play of the various parts, play being inherent to he machining of the parts.

In the embodiment shown in Fig. 6, balls 23 are also nserted between the .cam 9 and the cheek 16, the balls 23, due 5 their tight fitting, still providing a very flexible and ncoth driving of the movable cheek 1 with respect to the :ationery cheek 16, this again provides an easy taking up of le play.

Fig. 7 shows a construction identical to the instruction of Fig. 6, thus referred by the same numbers, but ιέ balls 11 are located within a plastics ball race 24, providing tween the cam 9 and slave gear 12 a friction preventing any cidental reversal of the articulation. 42363 Fig. 8 shows an articulation similar to the articulation of Fig. 1, but the balls 11 are located within a plastics race 25, identical to the race 24 and having the same purpose.

In Fig. 8, it can be seen that the cam 9 is directly resting at 9b on the movable cheek 1 so to ensure some braking still contributing to prevent any accidental reversal motion, owing to the tight fitting of the articulation.

It will also be noted that in order to achieve an 10 accidentally irreversible articulation the diameter of the cam 9 has been increased to minimize its ratio to the eccentrity.

Claims (3)

1. CLAIMS:1. A vehicle seat comprising an articulation between the seating and the back frame of the vehicle seat, the articulation comprising a stationary cheek fixed to the seating and so shaped to have an inner set of teeth ooacting with one set of teeth of a double slave gear mounted on a cam fixed to a shaft rotatably mounted and used as a central axis for the articulation, a second cheek fixed to the back frame and having an inner toothed ring ooacting with the second set of teeth of the above mentioned double slave gear, so to Obtain through a rotating motion of the slave gear driven by the cam and shaft, a smooth continuous motion of the cheek fixed to the back frame, characterised in that balls are inserted on one hand between the cam and the slave gear and on the other hand between the cam and the stationery cheek. •

2. A.vehicle seat as set forth in Claim 1, characterised in that a ball race is inserted between the balls and the slave gear.

3. A vehicle seat, substantially as hereinbefore described and illustrated in the accompanying drawings.