Safety device

A safety device comprises a body delimiting a passage having a safety rope passed through it, a ring connected by a strap to a belt, a brake and a system for locking the device to the rope should the worker fall. The device comprises a transverse spindle on which a toothed wheel is a relatively tight fit to constitute said brake, a cam mounted on the spindle and having teeth to cooperate with the safety rope and a weight cooperating with a pawl held away from a toothed ring attached to the cam by a spring, the weight being mounted in such a way that if the toothed wheel rotates at a speed greater than a specific threshold it causes engagement of the pawl with the toothed ring so that the cam teeth lock the safety rope into the passage.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention concerns safety devices for persons working at a great 
height. 
The invention concerns devices which are movable along a safety rope 
running vertically up a wall of a building, a tower or a pylon. 
2. Description of the Prior Art 
These devices comprise a body having a passage through which the safety 
rope passes, a brake cooperating with the rope and a ring connected by a 
strap to a belt or a harness worn by the worker, said ring being combined 
with a system designed to lock the device onto the rope should the worker 
fall. 
The ring is usually connected to a cam which wedges the safety rope against 
the opposite side of the passage if the traction force on the ring exceeds 
a particular value. 
These devices are very well known and are totally effective. They do have 
some drawbacks, however. They must be mounted on the safety rope in a 
particular orientation because they work in only one direction and if the 
worker falls they lock up instantaneously, which may cause injury. 
One object of the present invention is to remedy these drawbacks. 
SUMMARY OF THE INVENTION 
The present invention consists in a safety device comprising a body having 
two flanges delimiting a passage adapted to have a safety rope passed 
through it, said safety rope running vertically along a building or the 
like, a ring adapted to be connected by a strap to a belt or a harness 
worn by a worker, a brake adapted to cooperate with said safety rope to 
prevent said device sliding along said rope and means for locking said 
device to said rope should the worker fall, whereby said flanges are 
joined by a transverse spindle on which a toothed wheel is a relatively 
tight fit, said toothed wheel being adapted to cooperate with said safety 
rope to constitute said brake, a cam mounted on said spindle and having 
teeth adapted to cooperate with said safety rope and being urged into a 
position away from said rope by a spring, a weight mounted on said spindle 
cooperating with a pawl held away from a toothed ring attached to said cam 
by a spring, and said weight being mounted in such a way that if said 
toothed wheel rotates at a speed greater than a specific threshold it 
causes engagement of said pawl with said toothed ring so that said cam is 
rotated and said teeth lock said safety rope into said passage. 
This device is of simple design, secure in operation and functions 
progressively. 
The device preferably comprises two cams each having a toothed ring, two 
weights disposed one on each side of said toothed wheel and two pawls 
adapted to cooperate with respective toothed rings having oppositely 
directed teeth, said pawls being also oppositely directed and said ring 
being movable in a slot in said flanges so that it can be selectively 
disposed adjacent either end of said device. 
The device is therefore easier to fit to the rope because it can be fitted 
in either of two orientations at 180.degree. to each other. 
The cam preferably incorporates a sector-shape slot coaxial with said 
spindle and in which move fingers cooperating with the ends of a torsion 
spring wound around said spindle and adapted to urge said fingers against 
respective ends of said slot. 
A pin is preferably attached to and projects from both sides of said 
toothed wheel, said pawls can preferably pivot on said pin and said 
springs holding said pawls away from said toothed rings are preferably 
carried by pins attached to said toothed wheel and constituting abutments 
for said weights. 
The toothed wheel is preferably keyed to a ring rotatably mounted on said 
spindle and on which said weights are mounted. 
The flanges are preferably hinged together and said spindle is preferably 
attached to one flange and is hollow and internally screwthreaded to 
cooperate with a threaded rod for fastening said two flanges together. 
One specific embodiment of the invention will now be described in more 
detail by way of example only and with reference to the appended drawings.

DETAILED DESCRIPTION OF THE INVENTION 
The device shown in the figures comprises a body 1 made up of two flanges 2 
and 3 hinged together by a hinge 4 and delimiting a passage through which 
a safety rope 6 passes. 
The flanges support two pins 7 on which rotate rollers 8 which press the 
rope 7 against the opposite side of the passage 5. 
On the side opposite the passage the flanges comprise a sector-shape slot 
10 which guides a pin 11 attached to a ring 12. 
The flange 3 carries a rotatably mounted nut 12 into which is screwed a 
first part 13 of a threaded rod which has a second threaded part 14 of 
smaller diameter onto which is screwed a nut 15 which bears against the 
flange 2. A safety pin 16 is inserted in aligned diametral holes in the 
nut 15 and the threaded rod 14. 
The nut 12 includes a housing 17 into which is received the end of a sleeve 
18 which has a screwthread 19 into which the first part of the threaded 
rod is screwed. The free end of the sleeve 18 includes a shoulder 20 
bearing against the flange 2 and accommodated in a groove 22 on the 
respective side of the nut 15. 
To a ring 25 which is a moderately tight fit on the sleeve 18 is keyed a 
toothed wheel 26 cooperating with the safety rope 6 and constituting a 
brake so that the device does not to tend to slide along said rope under 
its own weight. 
Two weights 27 and 28 are a moderately tight fit on the ring 25, one on 
each side of the toothed wheel 26. The weight 27 has a flat 30 against 
which bears a pawl 31 hinged to a pin 33 attached to the toothed wheel 26 
where it projects from the respective side thereof, said pawl being 
pressed against said flat by a spring 32. 
The weight 28 has a flat 34 against which a pawl 35 hinged on the pin 33 
where it projects from the opposite side of the toothed wheel 25 is 
pressed by a spring 36. The springs 32 and 36 are retained by pins 37 
attached to the toothed wheel 26. 
A device 40 for locking up the device is mounted on the sleeve 18. 
The device 40 comprises two cam 41 and 42. On the side facing the passage 5 
the cam 41 has a smooth part 41a and teeth 41b and 41c symmetrical to a 
horizontal plane passing through the threaded rod 13. The part opposite 
the smooth part 41 incorporates a sector-shaped slot 45. A member 60 
comprising a circular opening in which teeth 56 are formed to constitute a 
toothed ring is fixed to the side of the cam 41 facing towards the toothed 
wheel 26. The cam 42 is of the same design as the cam 41 and has a smooth 
part 42a, teeth 42b and 42c and a slot 46. A member 62 incorporating a 
circular opening in which teeth 55 are formed to constitute a toothed ring 
is fixed to the side of the cam 42 facing towards the toothed wheel 26. A 
spacer 57 is inserted between the members 60 and 62 and has a circular 
notch 63 facing the toothed wheel 26. The members 60, 62 and 67 have 
respective slots 64, 65 and 66 aligned with the slots 45 and 46. The 
member 60 and 62 are cams corresponding to the cams 41 and 42. The cams 41 
and 42 and the members 60, 62 and 67 are assembled together by rivets 69 
passed through respective holes in said members. 
Each flange 2 and 3 comprises a slot 50 aligned with the slots 45 and 46. 
Fingers 51 and 52 are inserted in the various slots 45, 46, 50, 64, 65 and 
66. The finger 51 is urged by a respective end 71 of a torsion spring 70 
wound around the sleeve 18 against one end of said slots. The other end 72 
of said spring 70 urges the pin 52 against the other end of the slots 45, 
46, 50, 64, 65 and 66. 
The cams 41 and 42 are thus held in equilibrium with the smooth parts 41a 
and 42a facing the passage 5. 
the teeth of the toothed rings 55 and 56 are oppositely directed and the 
pawls 31 and 35 are also oppositely directed. 
The weights can pivot in only one direction because in the opposite 
direction the flat abuts on the pin 37. 
The device operates as follows: 
The person working at a great height wears a belt or a harness joined to a 
strap at the free end of which is a safety hook fixed to the ring 12. 
Referring to FIG. 3, the toothed wheel 26 cooperates with the safety rope 6 
and constitutes a brake preventing the device sliding freely along said 
rope 6. 
As the worker moves up and down, the device moves freely along the safety 
rope 6, the wheel 26 turning and its teeth cooperating with said rope 
Provided that the toothed wheel 26 moves slowly the weights 27 and 28 are 
entrained in the direction of rotation of the toothed wheel 26. 
Referring now to FIG. 9, should the worker fall the device moves along the 
safety rope in the direction of the arrow f. The toothed wheel 26 is 
rotated at high speed so that the weight 27, opposing the action of the 
spring 32, pivots the pawl 31 which engages in a tooth of the ring 55 with 
the result that the cams 41 and 42 are driven in the direction of the 
arrow g against the action of the branch 71 of the spring 70 as the finger 
51 is abutted against the respective end of the slot 46. The teeth 42c 
then bite into the safety rope 6 to lock the safety device to the rope 
(see FIG. 10). 
Referring to FIG. 9, the teeth 42c diverge from the ring 25 in the 
direction from the smooth part 42a towards the slot 46 so that the 
stronger the downward force the more securely is the safety device locked 
to the safety rope 6. 
All that is necessary to release the device is to move it in the direction 
opposite to the arrow whereupon the spring 70 returns the cams 41 and 42 
to their original position. 
The locking of the safety device to the safety rope is relatively 
progressive. 
If the device is fitted to the rope the other way around the operation is 
exactly the same except that in this case it is the pawl 35 which 
cooperates with the ring 56 to cause the device to be locked up, the pin 
11 sliding to the other end of the sector 10 so that the ring is at the 
bottom. 
The device is extremely simple to fit to the safety rope 6 as all that is 
required is to remove the threaded rod 13 in order to move the flanges 2 
and 3 apart by means of the hinge 4. 
Because the device operates in either direction, it can be mounted on the 
safety rope 6 without any particular precautions. 
Of course, the invention is not limited to the embodiment described and 
shown. Numerous modifications of detail may be made thereto without 
departing from the scope of the invention.