Longitudinal adjuster and vehicle seat

1. A longitudinal adjuster for a vehicle seat, the longitudinal adjuster having at least one pair of rails which is formed from a first seat rail and a second seat rail which is displaceable in the longitudinal direction relative to the first seat rail, wherein the seat rails mutually engage around each other so as to form an inner channel, wherein a spindle nut mounted with the second seat rail and a spindle operatively connected to the spindle nut are arranged in the inner channel, wherein a gearing which can be driven via a motor and interacts with the spindle is arranged at a front end of the first seat rail, wherein the spindle is radially fixed at a front end portion of the spindle in the gearing and radially fixed at a rear end portion of the spindle in a rotary bearing of the first seat rail,

wherein a first transverse bar is accommodated in a slot of the first seat rail upstream of the spindle nut in the longitudinal direction, wherein the spindle is guided through an opening of the first transverse bar in a contact-free manner, including with an encircling gap being formed, wherein a step of the spindle is arranged spaced apart forward in the longitudinal direction with respect to the first transverse bar, wherein, in reaction to a predetermined action of force including displacement of the first seat rail, the first transverse bar is clamped between the first seat rail and the step and a force from the first seat rail can thereby be diverted via the first transverse bar, the step, the spindle and the spindle nut to the second seat rail.

2. The longitudinal adjuster as claimed in claim 1 , wherein the rotary bearing supporting the rear end portion of the spindle is a second transverse bar.

3. The longitudinal adjuster as claimed in claim 2 , wherein the second transverse bar has a bearing opening for receiving a bearing bushing.

4. The longitudinal adjuster as claimed in claim 3 , wherein a further step is arranged on the rear end portion of the spindle, which step is mounted rotatably via a cylindrical first portion in a bearing bushing and is spaced apart by a radially enlarged second portion from the second transverse bar.

5. The longitudinal adjuster as claimed in claim 3 , wherein, in reaction to a predetermined action of force the second transverse bar is clamped between the first seat rail and the second portion of the further step, including by displacement of the first seat rail rearward relative to the spindle, and a force from the first seat rail can thereby be diverted via the second transverse bar, the further step, the spindle and the spindle nut to the second seat rail.

6. The longitudinal adjuster as claimed in claim 1 , wherein at least one of the transverse bars is of flat configuration.

7. The longitudinal adjuster as claimed in claim 1 , wherein at least one of the transverse bars is fastened at a contact surface which is directed upward in the vertical direction to the first seat rail, including via projection welding.

8. The longitudinal adjuster as claimed in claim 1 , wherein at least one of the transverse bars is accommodated with play parallel to the longitudinal direction in the respective slot of the first seat rail.

9. The longitudinal adjuster as claimed in claim 1 , wherein at least one of the transverse bars has projections which project laterally out of the respective slot of the first seat rail parallel to the transverse direction.