FR2512407A1 - Composite bumper switch bars for driverless vehicles - comprising metal strips backed by polyamide or polyolefin supports - Google Patents

Abstract

Concentric metal bumper bars designed to deflect or deform into mutual electrical contact if on a vehicle involved in a collision are of composite construction in which the non-opposed faces of the bars are supported by an ancillary bar of plastics materials. Used esp. for triggering the motor cut-out and/or braking system of a driverless vehicle following e.g. a rail or inductive cable guidance system in an industrial warehouse. The plastic support helps to pressure the elasticity of the metal strips if subjected to repeated minor impacts. The plastic layer on the outer face of the external bumper rail may be transparent, to reveal markings, such as yellow and black warning stripes, on the leading face of the bumper.

Description

Safety bumper for a movable member, in particular for a driverless vehicle.

The present invention relates to a safety bumper for a movable member, in particular for a driverless vehicle, provided with a control device capable of causing displacements of the movable member in the event of a collision between the bumper and a obstacle, said bumper comprising two flexible metal blades arranged close to one another and fixed to the front of the movable member so that, in the event of a collision, the outer blade is deformed to come into contact with the inner blade and establish with the latter an electrical connection connected to said control device.

When applying such devices on guided trolleys used in automated assembly lines, the metal blades which generally have a curved profile undergo numerous collisions whose impact points are located at the radius of the blades and in their central parts It is noted that after several deformations following collisions, the blades are deteriorated and more often than not have lost their own elasticity.

The fragility of the metal blades currently used and their significant cost have the consequences of causing disruptions in the general operation of the assembly line, presenting significant risks for the safety of people and greatly increasing the cost of returns from using self-guided carts
The present invention aims to provide a bumper which overcomes the aforementioned drawbacks.

To this end, the invention provides a bumper, characterized in that the external face of said external metal strip is provided with a first plastic reinforcing counter blade.
According to another characteristic, said inner metal blade is provided with a second plastic reinforcement counter blade.

The invention will now be described in detail with reference to the accompanying drawings in which - Figure 1 is a perspective view of a self-guided carriage
provided with a safety bumper known from the prior art - Figure 2 is a top view of a trolley provided with a bumper
safety shock performed in accordance with the teachings of the
present invention; and - Figure 3 is a detail view of the bumper shown in
Figure 2.

There is shown in Figure 1 a driverless vehicle consisting of a motor carriage 10 self-guided by means of a rail, or any other equivalent device such as for example a wire embedded in the ground.

The carriage 10 is provided at its front part with a safety bumper 14 comprising an exterior flexible metal blade 16 and an interior flexible metal blade 18. The two flexible metal blades are arranged parallel and close to one of the other and their ends 20 are fixed to the front of the carriage 10 by fixing means made of electrically insulating material so that the blades are isolated from one another.

The carriage 10 is provided with a control device (not shown) designed to cause its movements to stop stopping in response to a collision between the bumper 14 and an obstacle. In the event of a collision, the external metal blade 16 deforms until its internal face 20 comes into contact with the external face 22 of the internal metal blade 18 to establish an electrical connection between them. The ends of the blades are electrically connected to the control device so that the latter causes the carriage to stop as soon as said electrical connection is established.

According to the invention, and as shown in FIGS. 2 and 3, the external face 24 of the external metal blade 16 is provided with a first plastic reinforcement counter blade 26.

The internal face 28 of the internal metal blade 18 is also provided with a second plastic reinforcement counter blade 30.

The counter blades 26 and 30 have a shape complementary to the metal blades 16, 18 on which they are fixed so as to match the shapes at all points.

In order to ensure intimate contact between each counter blade and the corresponding metal blade, the attachment was made by means of rivets 32 uniformly distributed. Similarly, the ends of the four blades are pinched between insulating blocks 34 which also ensure the attachment of the entire bumper to the carriage.

In the case where the outer face 24 of the outer metal blade 16 is covered with visual safety symbols, such as for example alternating yellow and black rafters, the first reinforcing counterblade 26 can advantageously be made of a transparent plastic material.

The material chosen for the production of the reinforcing counterblades must have high mechanical properties: resilience, toughness, robustness and high resistance to impact and wear. Experience has shown that the counter blades could advantageously be made of polyamide or polyethylene.

The forming of the counter-blades can be carried out using a deformed template which perfectly matches the profile of the blades and by heating the material to around 200 using a steam torch.

The use of reinforcing counterblades eliminates the use of small rubber pads 36 provided on the devices of the prior art to maintain a constant spacing between the metal blades.

Claims (7)

1. Safety bumper (14) for a movable member (10), in particular for a driverless vehicle, provided with a control device capable of causing the movement of the movable member to stop in the event of a collision between the barrier shock and an obstacle, said bumper comprising two flexible metal blades (16, 18) disposed close to one another and fixed to the front of the movable member so that, in the event of a collision, the outer blade (16) is deformed to come into contact with the inner blade (18) to establish with the latter an electrical connection connected to said control device, characterized in that the outer face (24) of said outer metal blade (16 ) is provided with a first reinforcing counter blade (26) made of plastic. 2. Bumper according to claim 1, characterized in that the internal face (28) of said inner metal blade (18) is provided with a second reinforcement counter blade (30) made of plastic. 3. Bumper according to claim 1 or 2, characterized in that each of said counter-blades (26, 30) has a shape complementary to the metal blade on which it is fixed (16, 18) so as to match the shape in every way. 4. Bumper according to claim 3, characterized in that said counter-blades are fixed to the corresponding metal blade by means of rivets (32). 5. Bumper according to any one of the preceding claims, in which the external face of said external metal strip is covered with visual safety symbols, characterized in that said first counter blade is made of a transparent plastic material. 6. Bumper according to any one of the preceding claims, characterized in that said plastic material is a polyamide. 7. Bumper according to any one of the preceding claims, characterized in that said plastic material is a polyethylene.