Adjustable helmet

Description

The present invention concerns an adjustable head helmet for a vehicle driver, especially for the use of motorcyclists.

Adjustable helmets are known which can be discontinuously adjusted by taking off the helmet and modifying the length of internal straps, this solution having the drawbacks of interrupting the riding and a inadequate adaptation to the driver's head size.

The technical issue this invention addresses is to easily adapt the crash helmet to the head size of the driver who wears the said helmet, without being necessary to stop the vehicle.

The adjustable helmet according to this invention comprises a shell with a visor, provided with an interior isolation made of polystyrene or another material and an inner liner, the shell being provided with an air intake and three front, rear and lateral elastic bags placed on the inner liner of the helmet, wherein these bags are connected through tubes and a branch, and to a valve pump that allows the air to get into the three elastic bags.

The valve pump comprises an upper body connected through a screw thread with a middle body containing a spring that presses a ball, wherein the upper body is connected in a customary manner, using a screw thread, to a lower body provided at its lower end with a membrane pressed with a cap, the lower body being provided with a large hole and with a small hole, wherein an elastic element is assembled using a fixing element to the interior wall of the lower body, in line with the large hole.

The distance between the ball and the membrane may be adjusted by rotating the upper body inside the lower body in order to evacuate the air under pressure through the small hole.

The front elastic bag covers an angular zone in the cross-section of the helmet and perpendicularly to this, the lateral elastic bag covers an angular zone in the cross- section of the helmet, the bag volume being determined by the thickness of the

interior polystyrene isolation, and the rear elastic bag covers an angular zone in the cross-section of the helmet and perpendicularly to this.

The valve pump is mounted by pressing it into the polystyrene isolation.

The helmet user presses the pump membrane with the fingers, with a relative high frequency. The compressed air will overcome spring resistance lifting the ball over its support inside the middle body of the pump, allowing the compressed air to enter through the tubes in the front, rear and lateral elastic bags, until the desired stiffening of the helmet on the user's head is achieved. At each descending movement of the membrane the air will get in with high rate through the large hole and with low rate through the small hole. At each lifting of the membrane part of the inside air will be lost by laminary flowing through the small hole.

To partially or totally eliminate the compressed air from the system a constant pressure is exerted on the membrane until touching the ball, allowing this way the air to get out through the small hole. Considering that only a reduced quantity of air is necessary to adjust the helmet on the user's head, the drawback of loosing pressure through the small hole is compensated by the convenience of handling only one element, namely the membrane, both for fastening and releasing of the helmet.

For the particular case of a motorcyclist this solution is much more advantageous.

Usually a motorcyclist wears a loose helmet at low speed, in the cities, and a tighter one at high speeds.

The adjustable helmet according to this invention has the advantage of using a single helmet, directly adjusting the said helmet on the vehicle driver's head according to the road condition and speed.

An embodiment of the invention is described below in connection with the appended drawings, showing:

Fig. 1 — a cross-section through the adjustable helmet;

Fig. 2 — a section of the adjustable helmet in Fig. 1 along the axis A-A.

The adjustable helmet according to this invention comprises the shell 1 , the visor 2, the shell 1 being provided with an air intake 3. The shell contains inside an insulation

4 made of polystyrene (Styrofoam) or another material, an inner liner 5 and three elastic bags, a front elastic bag 6, a rear elastic bag 7 and a lateral elastic bag 8. Bags 6, 7 and 8 are interconnected through tubes 9 and a branch 10, and are also connected to a valve pump P.

The valve pump P presented in Fig. 2 comprises an upper body 11 connected through a screw thread with a middle body 12, having inside a spring 13 pressing a ball 14; wherein the upper body 11 is connected in a customary manner, using a screw thread, to a lower body 15 provided at its lower end with a membrane 16 pressed with a cap 17; the lower body 15 being provided with a large hole D and with a small hole d, wherein an elastic element 18 is assembled in a usual manner employing a fixing element 19 to the interior wall of the lower body 15, in line with the large hole D.

The distance between the ball 14 and the membrane 16 is h and may be adjusted by rotating the upper body 11 inside the lower body 15 in order to evacuate the air under pressure through the small hole d.

The elastic bag 6 covers an angular zone at of 30...90 degrees in the cross-section of the adjustable helmet and 45...90 degrees in the plane perpendicular to this section. The elastic bag 8 covers an angular zone αi of 30...90 degrees in the cross- section of the adjustable helmet, the bag thickness being determined by the thickness of the interior polystyrene isolation. The elastic bag 7 covers an angular zone CI ₃ of 30...90 degrees in the cross-section of the helmet and 45...90 degrees in the plane perpendicular to this section.

The valve pump P is mounted by pressing it into the polystyrene isolation 4.

This is the manner to operate the helmet and its adjusting system in order to fix it on the user's head:

The user of the adjustable helmet according to this invention exerts a pressure on the membrane 16 with a relative high frequency, i.e. 13 pushes per second. The air under pressure will overcome the resistance of spring 13 and will lift the ball 14 from its support, allowing the air under pressure to get in the front elastic bag 6, rear elastic bag 7 and lateral elastic bag 8 through the tubes 9 to achieve the desired stiffening of the helmet on the user's head.

By handling the membrane 16, the user may achieve an appropriate pressure to conveniently set the helmet on the user's head, eliminating the disadvantage of known helmets with imperfect accommodation to the head size.

At each descending movement of the membrane 16 the air will get in with high rate through the large hole D and with low rate through the small hole d. At each lifting of the membrane 16 part of the inside air will be lost by laminar/ flowing through the small hole d.

To partially or totally eliminate the compressed air from the system a constant pressure is exerted on the membrane 16 until touching the ball 14, allowing this way the air to get out through the small hole d. Considering that only a reduced quantity of air is necessary to adjust the helmet on the bearer's head, the drawback of loosing pressure through the small hole d is compensated by the convenience of handling only one element, namely the membrane 16, both for fastening and releasing of the helmet.

The handiness of the adjusting system of the helmet allows the driver to adjust the helmet on his/her head while running, according to the motorcycle speed. This way the driver is no more constrained to stop the vehicle to adjust the helmet straps for higher speed.