US3034435A

US3034435A - Striker mechanisms for igniters

Info

Publication number: US3034435A
Application number: US7700A
Authority: US
Inventors: Schermuly Alfred James
Original assignee: Schermuly Pistol Rocket Apparatus Ltd
Current assignee: Schermuly Pistol Rocket Apparatus Ltd
Priority date: 1959-02-16
Filing date: 1960-02-09
Publication date: 1962-05-15
Anticipated expiration: 1979-05-15
Also published as: GB869341A; NL110515C; FR1247869A; DE1121977B; NL248404A

Description

y 15, 1962 A. J. SCHERMULY STRIKER MECHANISMS FOR IGNITERS Filed Feb. 9, 1960 Fl .I

A/f/ed James Schermu/y By his af/omeys United States" Patent Ofi ice 3,034,435 ?aiented May 15, 1962 3,034,435 STRIKER MECHANISMS FOR lGNlTERia Alfred James Schermuly, Kingsdown, near Deal, England, assignor to The Schermuly Pistol Rocket Apparatns Limited, Newdigate, Dorking, England, a Br tish company Filed Feb. 9, 1960, Ser. No. 7,700 Claims priority, application Great Britain Feb. 16, 1959 4 Claims. (Cl. 102-70) The present invention relates to an improved striker mechanism for an igniter.

Striker mechanisms for igniters are known in which a movable striker is normally held by some form of latch mechanism in a retracted position against the action of a spring. By releasing the latch mechanism the spring is able to assert itself and drivethe striker against an igniter to cause actuation of the latter. Such striker mechanisms have the disadvantage that the striker spring is under considerable load from the time the strike-r is assembled therein until the striker mechanism is operated. If a considerable time elapses between assembly and use of the striker mechanism there is a danger that the spring will become weakened to such an extent that there is a danger of the igniter not being actuated when the striker mechanism is operated.

The present invention provides an improved striker mechanism for an igniter, comprising a body, a striker slidably mounted in the body and a member rotatably mounted on the body, about an axis co-axial with the slidin-g axis of said striker.

Preferably the rotatable member is in the form of a tube of circular cross-section having its longitudinal axis coincident with the sliding axis of the striker.

An igniter may be mounted in said body. Alternatively, the striker may be arranged to project from the body when it is driven by said spring means, to enable the striker to engage an igniter arranged externally of the body. For example, the igniter may be arranged at the end of a flare casing to which the body of the striker mechanism is secured.

One form of striker mechanism in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing, in which-- FIGURE 1 is a longitudinal sectional view of the striker mechanism taken along the line 1-1 of FIGURE 2, and

FIGURE 2 is a section taken along the line IIII of FIGURE 1.

The striker mechanism illustrated comprises a body 1 of circular cross-section which has two portions of different diameters axially aligned with one another. The portion 2 of larger diameter is axially counterbored at 3 and the portion 4 of smaller diameter has an axial hole 5 therethrough which opens into the counterbore 3. Diametrically opposed longitudinally extending slots 6 are provided in the wall of the portion 4- of the body 1, these slots extending from the free end of the body portion 4 to a shoulder 7.

A tube 8 of circular cross-section is received in the hole 5, which tube has an external diameter slightly less than the internal diameter of the hole 5. Diametn'cally opposed longitudinally extending slots 9 are provided in the wall of tube 8, these slots being aligned with, and having the same width as, the slots 6 and extending from the end 10 of the tube to a point near to the other end 11 thereof. A conventional percussion igniter 12 is mounted in the end 11 of tube 8, whilst the end 10 of the tube 8 is screw-threaded externally and receives an internally screw-threaded circular cap 13. The cap 13 has an external diameter which is greater than the diameter of the hole 5 in the portion 4 of the body 1. The

tube 8 has such a length that'when it is inserted in the hole 5 until the cap 13 bears against the free end of the portion 4 of the body 1, the percussion igniter 12 is located adjacent to the point where the hole 5 opens into the counterbore 3.

A striker, generally designated by the numeral 14, comprising a cylindrical head 15 and a cylindrical shank 16 of smaller diameter axially aligned with the head, is slid ably mounted in the tube 8. The striker head 15 has a diameter slightly lessthan the internal diameter of the tube 8. A striker point 17 is formed at the centre of that end of the head 15 which is remote from the shank 16. Two aligned, radially projecting arms 18 of circular cross-section project from the striker head 15, these arms having a diameter slightly less than the width of the slots 6 and 9. The striker 14 is received in the tube 8 with the striker point 17 facing the percussion igniter 12 and with the arms 18 projecting through the slots 6 and 9. A coil spring 19 is also received in the tube 8 surrounding the striker shank 16. One end of the spring 19 bears against the shoulder between the head 15 and shank 16 of the striker land the other end of the spring bears against the end ofoap 13.

A tubular member 20 is rotatably mounted on the body portion 2 and surrounds the portion 4 of the body 1. The tubular member 20 has one and turned into a peripheral groove 21 in the body 1 so as to allow rotation of the tubular member 20 on the body 1 but to prevent axial movement of the tubular member relative to the body. At its end remote from the body 1, the tubular member is closed by a plug 22, the plug being secured in the member 20 by a screw 23. The plug '22 has a central circular aperture 24 therein to receive the free end of the body portion 4 and this aperture is counterbored at 25 to receive the cap 13.

Two diametrically opposed cam parts in the form of cam surfaces 26 are secured to the internalwall of the tubular member 20 intermediate its ends. Each of the surfaces 26 is arranged at right angles to the wall of the tubular member 20 and extends around approximately of the periphery of the said wall along a substantially helical path. At its end lying farthest from :the plug 22, each cam plate 26 is provided with an axially directed stop 27 on the side of the plate facing the plug 22. The arms 18, which, as will become apparent hereinafter, act as cooperating cam parts or cam followers in association with the cam surfaces 26, are lightly urged by the spring 19 to bear against the sides of the cam surfaces 26 which face the plug 22. The position of the cam surfaces 26 in the axial direction of the tubular member 20 is so chosen that, when the tubular member 20 is in such an angular position relative to the body 1 that arm-s 18 bear on the cam surfaces 26 adjacent to the stops 27, the point 17 of the strikeris held a short distance from the percussion igniter 12.

If the tubular member 20 is now rotated relative to the body 1 in the direction of the arrow A, the helical cam surfaces 26 force the striker arms 18 along the slots 6 and 9 towards the plug 22, and the tension of the striker spring 19 is increased. During this movement of the striker 14 the end of the shank 16 remote from the head 15 passes through a hole 28 in the cap 13 and enters a recess 29 in the plug 22. When the member 20 has been turned through about 90 relative to the body 1, the ends of the surfaces 26 lying closest to the plug 22 release the arms 18 and the spring 19 urges the striker 14 along the tube 8 and drives the striker point 17 into the percussion igniter 12.

In the above described striker mechanism the striker spring 19 is not under any considerable tension until immediately before the mechanism is operated. Consequently there is no danger of the spring becoming weakened through being tensioned for a considerable period of time.

The striker mechanism may be provided with any suitable safety device for preventing accidental or unintentional rotation of the tubular member 20. In the example illustrated a removable split pin 31? is provided to lock the tubular member 20 to the body portion 4.

The above described striker mechanism may be mounted in one end of the casing of a pyrotechnic device, such as a flare. To this end, the body portion 2 may be provided with a peripheral groove 31 into which the casing of the pyrotechnic device may be oannelured.

The invention is not, of course, limited to the particular form of striker mechanism described in detail above, and changes in structural design can clearly be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A striker mechanism for an igniter comprising a body, a striker slidably and non-rotatably mounted in said body, a striker point forming one end of said striker, a percussion igniter mounted within said body in the sliding path of said striker and confronting said striker point, a tubular member rotatably mounted on said body to surround said striker, the axis of rotation of said tubular member being coaxial with the sliding axis of said striker, a striker spring engaging said body, surrounding said striker and urging said striker point towards said igniter, two aligned arms projecting from the striker at right angles to the sliding axis thereof, two cam surf-aces projecting inwardly from said tubular member, spirally with respect to the longitudinal axis of said cam-surfacebearing tubular member, and diametrically disposed on the internal surface thereof, each cam surface extending over a determined arc of less than 180, one aligned arm resting on each of said surf-aces; whereby the spring is not compressed until firing time, rotation of said camsurface-bearing tubular member, through at most said de termined arc, slidably forces the 'arms up along the cam surfaces and the striker point away from the igniter until the cam surfaces end and release the arms and the striker point is driven by the spring into engagement with the igniter.

2. A striker mechanism for an igniter as in claim 1 having a tube non-rotatably, centrally and vertically disposed within the said body, slidably receiving the striker and having diametrically opposed longitudinally extending slots to receive the aligned projecting striker arms; whereby the said striker is firmly held against the clockwise cocking rotation of the oam-surface-bean'ng tubular member.

3. A striker mechanism for an igniter as in claim 2 wherein there are vertically disposed stops mounted on the low ends of each of the cam surfaces which stops, when in alignment with the striker arms and slots of the non-rotatable tube, act in conjunction therewith to prevent the counterclockwise rotation of the cam-surfacebearing tubular member and subsequent release of the striker, even lightly loaded.

4. A striker mechanism for an igniter as in claim 1 in which a removable split pin is inserted through the Walls of the rotatable cam-surface-bearing tubular mem her and slot bearing non-rotatable tube to thus prevent unintentional rotation of the said cam-surface-bearing tubular member.

References Cited in the file of this patent UNITED STATES PATENTS 1,794,411 Lalurniere Mar. 3, 1931 2,382,872 Giles Aug. 14, 1945 2,839,017 Smith June 17, 1958