FR2755236A1 - Tension or shock sensor with radio alarm for protection of person or in industry - Google Patents

Abstract

The sensor is usually connected between a safety harness and an anchoring point using upper and lower rings (4,20). The lower ring (20) has a rod (15) held stationary within a head (16) by a flange which contains a contactor (14) and operating button (13). The upper ring (4) also has a rod (5) which passes through a head (8) and is connected to a piston (11) normally held against the operating button (13) by a spring (10). Under extreme tension the piston moves releasing the button (13) and operating the contactor (14) to produce a radio alarm (23). Mechanical strength is provided by a steel cylinder(1).

Description

 The present invention relates to a force sensor adaptable to a fall arrest harness for working at height or dangerous. This sensor can also be used on devices requiring a limit on the tensile force. The radio alarm triggered after an over-effort incident allows rescue organizations to intervene immediately.

The framework of the device is constituted by a cylinder (1) of very thick stainless steel in order to receive an internal thread and to resist tensile forces.

Around this cylinder is fixed a plastic material box with high impact resistance, intended to shelter the radio-transmitter device. Inside the cylinder (1) is arranged the force sensor system and the trigger device activating the radio alarm transmitter.

The force sensor system comprises at its upper part a movable peg (4) for the attachment of a safety cable, and at its lower part another fixed peg (20) whose rod (15) is welded to a cylinder head (16) itself welded (17) in the cylinder (1). On this piton (20) are fixed the cable or the harness supporting the people or the devices to be protected in the event of a fall.The rod (5) of the piton (4) slides in a cylinder head (8) screwed in the upper part of the cylin hard (1). The end of this rod is threaded and receives a steel guide piston (11), a key ensures its blocking.

Between the cylinder head (8) and the movable piston (11) is placed around the rod a calibrated spring (10) according to the force to be maintained.

This rod (5) maintains in its cut-off position the button (13) of an electrical contactor (14) connected to the alarm transmitter. When the spring is compressed as a result of exceeding the planned load, following an abnormal tensile force, the button (13) is released by the advancement of the rod (5) and the radio alarm is activated.

The cylinder head (8) in which the rod (5) of the bolt (4) slides has a groove provided with an O-ring (9) to seal the device. An internal circlip (7) prevents the cylinder head from unscrewing; this is provided with notches to facilitate its blocking in the cylinder with a lug wrench. The stroke of the rod (5) is limited relative to the button (13) of the contactor (14) by a spacer (6) bearing on the cylinder head (8). The contactor (14) is fixed on the lower fixed cylinder head ( 16) from inside the cylinder before installing the upper cylinder head (8). The output wires of the contactor (14) pass through the wall of the cylinder and are connected to the radio control box by a special suitable connector (22). The box (2) containing the radio-transmitter device is fixed on a stainless steel flange
(3) welded (17) on the upper part of cylinder (1). This plate is provided with a falling edge which overlaps the housing (2) in order to ensure sealing. A joint can be provided between the elements (2-3). The underside of the housing (2) whose lateral edges extend beyond the bottom serves as a housing for the transmitting antenna (18) and receives a coaxial socket for recharging without dismantling the accumulator. This box is divided into two compartments (23 and 24) which receive respectively: the card of the transmitter and the card of the accompanying electronic elements (25- power supply, coding, ect ...). It should be noted that all of the mechanical components of this device will be either stainless steel or plastic to withstand the weather.

The operation of this device is as follows: the force sensor whose spring is calibrated according to the desired tripping load is placed when it comes to protecting an operator, either between the harness buckled on it and the cable or the restraint line with a fall arrest device, either between the point of attachment of the cable or restraint line and said cable or cordage. In the event of the operator falling, the force generated will compress the calibrated spring (10) and open the contactor circuit which will activate the radio transmitter; the signal transmitted will be recorded by a receiver fitted with an audible and visual alarm. The range of the transmitter will be approximately 200 to 400 meters, area in which the receiver must be positioned. This device will rescue an operator who, having fallen, remains hanging from the end of the retaining cable and cannot free himself alone without risk.

Monitoring can be carried out for several operators taking into account that each transmitter will have a different call code; it will also be possible to locate the source of the calls.

This security system will be subject to the approval of the competent administrative services and will be subject to periodic regulatory checks.

LANDMARKS
Cylinder constituting the framework of the device
Plastic housing receiving the radio transmitter
Stainless steel housing fixing flange (2)
Mobile hooking pin
Movable peg rod (4)
Spacer for positioning the rod of the movable peg
Internal retaining ring for locking the cylinder head (8)
Bolt in which the bolt rod slides, screwed
in the cylinder (1)
O-ring seal between cylinder head and bolt rod
Spring calibrated according to the desired release force
Movable piston for guiding and supporting the spring screwed at the end
the rod (5) of the piton (4)
Movable piston locking pin (11) on the rod (5)
Button of the electrical contactor activating the radio transmitter
Electric contactor activating the radio transmitter
Stem of the lower fixed stud (20)
Cylinder head receiving the piston rod (15), welded thereon
and welded into the cylinder
Welding bead
Transmitting antenna
Coaxial socket for recharging the battery
Fixed hook
Notches in the cylinder head (8) for lug wrench
Connection connector between contactor (14) and transmitter
radio
Housing compartment (2) receiving the radio transmitter
Housing compartment (2) receiving the accumulator
Compartment electronic cards (23)

Claims (9)

 the alarm radio transmitter.  mechanical and the electrical contactor (14) operating  dre (1) in steel in which the elements are positioned  that the framework of this one is constituted by a cylin  1) Force sensor with radio alarm, characterized in that 2) Force sensor with radio alarm, as claimed  tion 1, characterized in that the cylinder (1) is threaded  11 inside to receive a cylinder head (8) in the  which slides the rod (5) of the stud (4). 3) Force sensor with radio alarm, as claimed  1 and 2, characterized in that the rod (5) is provided  at its end of a piston (11) screwed thereon and  blocked by a key (12). 4) Force sensor with radio alarm, according to claims  1, 2 and 3, characterized in that the tensile lteffrt  exerted on the assembly: piton (4) rod (S), piston (11) is  balanced by a calibrated spring (depending on the expected force, 5) Force sensor with radio alarm, as claimed  1,2,3 and 4-, characterized in that the cylinder. (1)  receives at its lower part a fixed peg (20) whose  rod (15) is welded to a cylinder head (16) which is itself welded  in the cylinder (1). 6) Force sensor with radio alarm, as claimed  1w2,3,4-et5characterized in that the cylinder head (8) in  which slides the rod (5) of the stud (4) is provided with a  groove provided with an O-ring (9) ensuring sealing  internal of the device and is fitted with a retaining ring  maintenance in the cylinder. 7) Force sensor with radio alarm as claimed  1,2 and 3 characterized in that the rod (5) on the side  piston (ll) keeps the button in the cut-off position  (13) of the electrical contactor (14).  comprising two compartments (23-24).  in a housing (2) arranged around the cylinder (1), and  tion 1, characterized in that the radio transmitter is fixed  8) Force sensor with radio alarm, according to r.evendica 9) Force sensor with radio alarm, as claimed  1 and 8, characterized in that the Qmet antenna trice (18) and the coaxial socket (19) for recharging the accumulator are fixed on the underside of the housing (2).