GB2072815A

GB2072815A - A line-thrower

Info

Publication number: GB2072815A
Application number: GB8108682A
Authority: GB
Original assignee: GOTEX AB
Current assignee: GOTEX AB
Priority date: 1980-03-25
Filing date: 1981-03-19
Publication date: 1981-10-07
Also published as: FR2479128A1; GB2072815B; SE8002268L; NL8101486A; JPS56149600A; DE3111044A1

Abstract

A line-thrower comprises a cylindrical housing (10) and a discharge tube (16) fitted centrally therein in such a manner that a chamber (18) for storing a spool of line (21) is provided. During a feeding-out from the inside towards the outer portion of the spool the resistance will gradually increase during the passage of the line through an opening (20) in a shield (19). The braking action may be increased by the marginal portions (45) of the spool being impregnated with glue. A rocket (25) is located within the discharge tube and has a firing mechanism (26) at its forward end, which is accessible through a restricted throat (12) of the housing. A connection between the rocket (25) and the line (21) is obtained by means of a sleeve (33), which is slideable along the rocket towards a shoulder (35) at the rear end thereof. The sleeve carries a bridle (34) of flexible, non-combustible material. The bridle has sufficient length to permit the rocket (30) to be removed from its discharge tube, for replacement without disturbing the line. A soft metal wire (37) is attached to the bridle and is wound several turns around the discharge tube before it is attached to the line (21). The discharge tube comprises a tubular portion (16a), which is fitted to the bottom (17) of the discharge tube, by means of an easily breakable member (42) so that the tubular portion (16a) is pulled along by the metal wire (37) during the initial stage of the launching. <IMAGE>

Description

SPECIFICATION A line-thrower This invention relates to a line-thrower. For life saving at sea, and elsewhere where it is also desirable rapidly to bring about a connection between two positions, for instance between two ships, between one ship and the shore, or between two points separated by water, a line thrower is often used. Such a line-thrower comprises a length of line, one end of which is attached to a rocket, while its other end is anchored in a suitable manner at the location of launching the rocket.

The capacity of line-throwers is determined by international conventions. The strength of the line shall thus be at least 2000 N, and its length shall be at least 230 meters.

With known designs of line throwers, the terminal end of the line has been provided with means for anchoring it at the site of launching, close by the operator, and on many occasions the portion of the line extending between the linethrower and the anchoring has hindered the feeding-out of the line. It may be difficult to find a suitable anchoring ground, and the jerk caused when the line is fully stretched may cause a recoil, which twists the line. If the line has been attached to a thicker rope, which is to be passed on to the target, part of the rope may be pulled out even if the rocket misses the target. The rope will then have to pulled back and coiled before a new rocket can be launched. It oftens happens that the line issues as partly intertwined tangles, which reduce the effective range, and also tend to guide the rocket sidewards.The connection between rocket and line has furthermore often been designed so as to cause detrimental deviations sidewardly, or in relation to the intended elevation.

A general object of the present invention is to provide a line-thrower, where most drawbacks of older types of line-throwers have been removed.

With particular preferred embodiments of the invention, a more specific object is to provide a line-thrower where a good guiding of the path of the line is obtainable, where it is possible to anchor the line in the housing of the thrower, without the risk of detrimental jerks occurring, and where the feeding-out of the line may be braked in a simple manner if such action should be needed.

A line-thrower of the type intended here is stored in a protected place, and must be readily available for use. The rocket will have to be substituted after some time, for instance every third year, in order to ensure a safe functioning, and it is important that exchange of rockets can be performed with only a small disturbance of other components. The design of the rocket is further of major importance for ensuring a suitable trajectory and the capacity to reach the intended target.

A line-thrower according to the invention comprises a housing having a discharge tube located centrally therein for receiving a rocket, together forming an annular chamber for a line connected to the rocket, and is characterized in that the housing has a cylindrical form, with a restricted throat and a removable bottom, and that the discharge tube has such a length that it extends from the bottom of the housing to the throat to leave a firing mechanism at the forward end of the rocket accessible through the throat.

The line is preferably wound into a selfsupporting spool of the type where, during the winding up, the line performs a guided reciprocatory, axial movement in relation to a rotatable spindle, which is removable after the winding operation and has a larger diameter than the discharge tube, whereby a central passage for feeding-out the line will be formed. It will then be possible to produce pre-coiled lines in a factory for insertion in the housing before its bottom is fitted.

Such spools will have a very compact structure and provide a safer feeding-out than with the embodiments where the line is fed by hand into the housing.

A shield insertable in the upper end of the housing and having a central opening for feedingout the line is preferably provided, said opening having a larger diameter than the discharge tube and substantially the same diameter as the central passage in the line spool. The shield and the bottom of the housing are outwardly vaulted, whereby the line spool will be subjected to pressure along its envelope portion when the bottom is being fitted in the housing.

In order to increase the braking action the coils in the envelope portion of the line spool may be bonded together, for instance by glue, to promote braking.

A sleeve surrounding the rocket is preferably applicable to the forward end of the discharge tube, and carries a bridle of flexible, noncombustible material, to which the line is attached, the length of the bridle being selected so as to permit the sleeve and the rocket to be lifted from the discharge tube without stretching the attached end of the line. Hereby it will be possible to substitute the rocket without any ingress upon the line spool or the discharge tube.

Rockets of this type, and for similar use, have hitherto always been ignited by way of the exhaust nozzle. The fire front within the rocket will then always have to force, at an increasing counter pressure, a bubble of gas before itself, until the full fire surface has been ignited, which will result in a comparatively "slow" rocket. According to the invention the firing mechanism is fitted at the forward end of the rocket, and the charge of the rocket is formed with an axial passage. This will permit an instantaneous travel of the firing front from the firing mechanism at the forward end of the rocket to its jet end.

The mouth of the throat has a smaller diameter than the spool chamber and is adapted for cooperation with a removable lid, whereby a space will be formed for the reception of components necessary for the firing of the rocket, but not required to be accessible during storage.

The discharge tube is preferably provided with a stationary bottom and a tubular portion, severable therefrom, but retained at the bottom by means of a releasable catching means. The tube will be pulled along, when the rocket is launched, but will fall to the ground just outside the housing.

The line is securely coiled in the spool, and when the center thereof is free of obstacles, it will be possible to reduce the extension of the firing range by inclining the housing, so the friction between the line and the opening in the shield is increased.

It will even be possible to turn the housing upside down, so the line will grind against the ground, or other support for the operator.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a section through a linethrower according to the invention, with its lid removed and ready for firing; Figures 2 and 3 show an elevation and an end view, respectively, of a line spool, illustrating the principle for coiling the line; Figures 4 and 5 show a vertical and a horizontal section, respectively, through the line spool; and Figures 6 and 7 show cross-sections through line spools, which have been partly impregnated by glue in various ways.

The line-thrower shown in Figure 1 has a cylindrical housing 10, with a reinforced bottom 1 and a somewhat restricted throat 12 having an external thread 13. A lid 14, provided with an internally threaded portion and a rope handle 15, will be fitted to the housing during storage for protecting the components contained in the housing.

A discharge tube 16, a so-called mortar, likewise having a reinforced bottom 17 is mounted centrally in the housing 10, so that an annular chamber 18 is formed around the discharge tube. A line spool, of a type to be described in connection with Figures 2 to 7, is fitted in this chamber. The chamber is outwardly defined by a shield 19, which has a centrally located opening 20. This will, with a clearance at least corresponding to the thickness of the line 21 to be used, enclose the upper end of the discharge tube 1 6. The terminal end 22 of the line is attached to the shield 19, adjacent to the housing 10. The forward end 23 of the line issues from the lower portion of the line spool, and the clearance 24 between the spool and the discharge tube is sufficiently wide to permit the line end 23 to be extended upward, approximately to the shield 1 9.

The line is coiled irl the manner common with twines and pack-wnreads, i.e. the line will during the winding operation, be brought to perform a guided reciprocatory movement in relation to the axis of a rotatable center spindle. When the spool is complete, and a possible fixation of the outer contour of the spool has been performed, the spindle is removed. The diameter of the spindle is selected to be somewhat larger than that of the discharge tube. In this manner a self-supporting spool without any central core is obtained, from the inside of which the line may be extracted. The basic appearance of such spools can be seen in Figures 2 and 3.

The shield 19, as well as the bottom 11, has an outwardly vaulted form in relation to the line spool. The spool will be fitted into the housing - while the rear end of the housing is still open.

When the bottom is forced into the housing the spool will be subjected to pressure alongs its envelope portion, which will retain the spool, and furthermore will increase the resistance to uncoiling during the later part of the feeding-out of the line.

A rocket 25 is fitted into the discharge tube, which projects above the shield 1 9. In a mounted position the rocket will project outside the discharge tube. In contradistinction to rockets hitherto used with line-throwers of known designs, the rocket is here provided with a firing mechanism 26 located at the end thereof which is accessible from the mouth of the housing. The firing mechanism comprises, in a well known manner, a percussion cap 27, a firing pin 28, and a triggering wire 29 for the latter. A number of annular charges 30 are fitted between the firing mechanism and a jet nozzle 31 of the rocket.

Foliowing an ignition, the fire front will instantaneously pass through the central passage 32 through the charges.

A sleeve 33 having sidewardly extending ears fitting into slots at the discharge tube 1 6 will be mounted thereat. A bridle 34 of flexible, noncombustible material, for instance a soft wire or a chain, is attached to the ears. The sleeve is designed in such a manner that it will slide downwards along the rocket during the discharge thereof, or more correctly, the rocket will pass upwards through the sleeve. A shoulder 35 at the rear end of the rocket will finally catch and retain the sleeve, whereupon the bridle will be freely suspended behind the rocket. One end 36 of a soft metal wire 37, wound several turns around the discharge tube is attached to the bridle. The other end 38 of the metal wire is connected to the forward end of the line, extending upwards through the clearance between the spool and the discharge tube.This part of the line is protected by a heat-resistant cover 39.

The length of the bridle is selected so that the rocket, after a predetermined period of time, may be lifted from the discharge tube to be substituted, without the metal wire 37 and the line attached thereto being disturbed.

The bottom 1 7 of the discharge tube is securely attached to the bottom 11 of the housing. In addition to the bottom, the discharge tube comprises a detachable tube portion 16a, which is secured to the discharger bottom 17 by means of a fine metal wire 42, which is passed through mating holes in the tube and in the bottom. This wire is extended to, and attached to the bridle 34.

When the rocket is fired, the wire 42 will be pulled out from the bottom so that the tube portion 1 6a becomes free. It will follow the bridle outwards, but soon falls to the ground.

The wire 37 between the bridle and the line will of course, during the initial stage of the launching exert a pulling force upon the discharge tube, and instead of the securing wire 42 it will, on many occasions, be sufficient to provide breaking pins, or other easily removable members between tube portion 1 6a and the bottom 17.

An annular body 16b of a material easily destroyed by the heat, for instance foamed plastics, is provided to support the upper end of the discharge tube during storing and handling.

When the rocket is in flight the bridle, and thereafter the metal wire 37 will pull the line along, axially behind the rocket. The rocket is ignited from its end remote from the exhaust nozzle 31 , which means an instantaneous firing all along the inward surface, and a rapid through-flow of gases. The rocket will thus have already gained so high a speed when it leaves the discharge tube, that the guiding braking force from the line is fully developed (about 20 N), The braking force during the accleration of the rocket at the moment of discharge is of significant importance for directing the rocket.

The rocket is, according to established rules, designed to pull out a minimum of length of a line of a certain character. The line chamber 1 8 is now designed so that it has a capacity to receive a line, having a length exceeding the greatest practical trajectory of the rocket. As the feedingout of the line occurs from the inside of the spool, towards it outer position, and which furthermore can be done without the risk of tangles suddenly passing out, the line will gradually be subjected to an increased resistance while passing out through opening 20 in the shield 1 9. The line will run out, loop after loop, from the central passage, but as the loops gradually approach the wall of the housing, the increasing bending of the wire within the chamber will imply an increased resistance.A strong wind from behind tends to increase the range, but it is possible to increase the braking action by altering the inclination of the housing, as need be. As will be evident from the description in connection with Figures 4 to 7 the resistance may be increased by the envelope portion of the spool being impregnated with glue.

To facilitate handling during the firing, the housing is provided with a handle 40, which is attachable to the housing by means of two screws 41. The space between the shield 1 9 and the mouth of the throat is designed in such a manner that the removed handle 40, as well as dismounted components of the firing mechanism, can be stowed therein, before the lid 1 4 is fitted.

In this manner these components will be safely retained within the housing during the storing of the line-thrower.

Figures 2 and 3 show a spool of a type common for dispensing twine and pack-threads, and is adapted to operate without any central support.

The inward end 23 of the line will be accessible from the passage 43, which is formed in the center of the spool. The opposite end 22 of the line is found adjacent the edge of the spool and at the end thereof to be turned upwards, when fitted into the housing.

in order to increase the braking action it is possible, in the manner indicated in Figures 4 and 5, to impregnate the envelope portion of the spool with glue. In Figures 4 and 5, the core 44 of the spool is not affected by glue, whereas the outward, cross-hatched portion 45 is impregnated with glue. The impregnation is preferably arranged so the radial measure of the glued portion 45 increases in the direction from above towards the bottom of the spool.

Figures 6 and 7 show cross-sections through line spools 46 and 47. In Figure 6 the spool has been rolled in glue, so this glue could enter from opposite directions, just into one half of the spool, and then into the other half. According to Figure 7 four different sides of the spool have been partly dipped into glue, which thus could enter from all directions, but could penetrate to different depths.

The last two mentioned examples will provide a more distinct shape and extension of the impregnated part of the spool, than with the embodiment according to Figures 4 and 5.

In the specification and in the claims expressions such as up and down are sometimes used for simple identifications, and shall be understood as referring to the position shown in Figure 1 , which shows the line-thrower ready for launching. During the launching proper, the housing, and thus the rocket, will be inclined depending upon the intended trajectory and possible side wind.

Claims

1. A line-thrower comprising a housing having a discharge tube located centrally therein for receiving a rocket, together forming an annular chamber for a line connected to the rocket, characterized in that the housing has a cylindrical form, with a restricted throat and a removable bottom, and that the discharge tube has such a length that it extends from the bottom of the housing to the throat to leave a firing mechanism at the forward end of the rocket accessible through the throat.

2. A line-thrower as claimed in Claim 1, characterized in that the line is wound into a selfsupporting spool of the type where, during the winding up, the line performs a guided reciprocatory, axial movement in relation to a rotatable spindle, which is removable after the winding operation and has a larger diameter than the discharge tube, whereby a central passage for feeding-out the line will be formed.

3. A line-thrower as claimed in Claim 2, characterized in a shield insertable in the upper end of the housing and having a central opening for feeding-out the line, said opening having a larger diameter than the discharge tube and substantially the same diameter as the central passage in the line spool.

4. A line-thrower as claimed in Claim 3, characterized in that the shield and the bottom of the housing are outwardly vaulted, whereby the line spool will be subjected to pressure along its envelope portion when the bottom is being fitted in the housing.

5. A line-thrower as claimed in either Claim 3 or Claim 4, characterized in that the coils in the envelope portion of the line spool are bonded together to promote braking.

6. A line-thrower as claimed in Claim 5, wherein said coils are bonded together by glue.

7. A line-thrower as claimed in any one of the preceding claims, characterized in that a sleeve surrounding the rocket is applicable to the forward end of the discharge tube, and carries a bridle of flexible non-combustible material, to which the line is attached, the length of the bridle being selected so as to permit the sleeve and the rocket to be lifted from the discharge tube without stretching the attached end of the line.

8. A line-thrower as claimed in Claim 7, characterized in that the discharge tube outside of the shield carries a soft metal wire wound several turns around the tube and forming a connection between the bridle and the forward end of the line.

9. A line-thrower as claimed in either Claim 7 or Claim 8, characterized in that the length of the line is greater than the practical range of the rocket, and that the shield is provided with means for retaining the terminal end of the line.

10. A line-thrower as claimed in any one of the preceding Claims, characterized in that the charge of the rocket is formed with an axially extending passage for causing an immediate passage of the ignition front from the firing mechanism at the forward end of the rocket to a nozzle end thereof.

11. A line-thrower as claimed in any one of the preceding Claims, characterized in that the mouth of the throat has a smaller diameter than the spool chamber and is adapted for cooperation with a removable lid, whereby a space will be formed for the reception of components necessary for the firing of the rocket, but not required to be accessible during storage.

12. A line-thrower as claimed in any one of Claims 8 to 11, characterized in that the discharge tube comprises a stationary bottom and a tubuiar part separable therefrom, and is retained to the bottom by means of a releasable member.

1 3. A line-thrower substantially as hereinbefore described with reference to and as shown in the accompanying drawings.