US2625881A - Double element setback lock - Google Patents

Description

Jan. 20, 1953 J. RABxNow DOUBLE ELEMENT sETBAcx Locx 2 SHEETS-SHEET 1 Filed Aug. 3, 1949 Siwa/Wto@ JADDE RAenNnw Jan. 20, 1953 J. RABiNow DOUBLE ELEMENT sETBAcx Loox 2 SHEETS-SHEET 2 Filed Aug. 31 1949 gmac/nio@ JADE@ RAEIINUW Patented Jan. 20, 1953 UNITED STATES PATENT OFFICE 2,625,881 DOUBLE ELEMENT SETBACK LOCK Jacob Rabinow,.Washington, D. C., assignor to the United States of America as represented by the Secretary of the Army 1 Claim.

sec. 266) Theinvention described herein may be manufactured and used by or for the Government for governmental purposes without payment to me of. any royalty thereon.

This invention relates to a safety setback lock or release for ordnance devices and more particularly to a device for arming the fuse of an ordnance missile only after a predetermined periodr` of. sustained acceleration such as occurs, for example, in the disch-arge of a rocket.

In ordnance missiles, which commonly carry explosive charges, it is desirable that the missiles remain safe or unarmed.until after they have been fired. This ensures maximum safety of the using personnel, yet enables the explosive to cause damage to the target. Various means are used to secure this result. For example, rotating missiles may be equipped with arming mechanisms which are responsive to the centrifugal forces developed when the lmissile is fired. Nonrotating missiles, such as mortar shells, certain classes of rockets, and the like, are ordinarily equipped with arming mechanisms which are responsive to the forces of setback, which occur when the missile is launched.

Until very recently, many such arming devices were not shockproof, and the missile could accidentally be' placed in the armed condition if it were dropped or otherwise subjected to a strong mechanical shock.

The present invention deals with a particular vspecies of double element release which is respons'ive tov sustained acceleration only, and which may be rapidly, easily and cheaply manufactured on screw machines. While my device may be produced in any convenient size, for the purposes of economy of cost and space, and ease of manufacture, I prefer to make the device approximately 1A, inch in maximum diameter and approximately l inch in length, or smaller.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing, in which Figure 1 is a longitudinal section of a projectile detonator or fuse nose embodying my invention.

Figure 2 is a longitudinal section to a greatly enlarged scale of the setback safety lock shown in Figure l, in its initial or safe condition,

Figure 3 is a sectional view of part of the device shown in Figure 2, showing an initial phase of the action.

Figure 4 is a view similar to Figure 3 showing the final armed position of the safety lock.

2 Figure 5 is a cross section taken on line 5-5 of Figure 2. y

Figure 6 is a cross section taken on line 6--6 of Figure 4.

Figure 7 is a view similar to Figure 3 showing the action due to a nonsustained shock.

Figure l shows an example, for the purpose of illustration, of an organization employing safety release or lock, which is indicated generally at30. The fuse ZI is adapted to be' screwed into the nose of a projectile by means ofy threads 22. A transverse bore 23 is closed by threaded block 24 and contains a plastic slidable element 21, which may be suitably'keyed to prevent rotation in the bore, this element being biased to the right in Figure 1 by spring 25, and restrained against displacement by my safety setback release generally indicated at 30. Part of the release element projects into recess 3i in b0re23 to prevent motion of slidable element 21. It will be apparent that as this projection 3l is withdrawn into safety release 30 the slidable element 21 will move to the right until detonator 28 is aligned with firing pin 33y to arm the fuse in known fashion. Upon impact the detonator will be fired by pin 33 which will in turn set. off booster 24 to explode the projectile charge. It will be understood that in place of the impact mechanism shown any other type of fuse mechanism may be employed. My invention is concerned primarily with the safety setback release mechanism which will be described in more detail below with reference to Figures 2 to 7.

In each of these. figures, I` isa weight which is free to move in one direction'insidea second weight or latch 2. Weight I is forwardly pressed by spring 4, and is retained in weight 2 by a lip 2a formed thereupon. Weight 2 is free to move in one direction in sleeve 3, and is retained therein by lip 3a which is formed thereupon and bears upon shoulder 2b formed in weight 2. Weight 2 is forwardly pressed in sleeve 3 by spring 5. Ball 6, when the device is in the unarmed position, Figure 1, rests with slightly more than half its diameter in hole 2c of weight 2, and slightly less than half its diameter in hole 3b of sleeve 3, locking weight 2 to sleeve 3. The diameter of hole 3b is slightly less than the maximum diameter of ball 6; this prevents ball 6 from passing through hole 3b and becoming disassembled from the device While the `device is' in the unarmed position of Figure l.

When setback occurs, as when the missile is fired, weight I, responsive thereto, moves rear- Wardly against the force of spring 4. This motion causes the constricted portion la of weight I to be brought into juxtaposition with ball 6, which is thus freed to move inwardly and is urged to do so bythe contour of hole 2c.

If themissile has been accidentally dropped, as against a hard surface, the setback force is only momentary, and the sloped shoulder I b of weight I returns ball 6 to its original position, locking sleeve 3 and weight 2, when weight I is forwardly pressed by spring 4.

1f, however, the missile vhas been launched, setback force is sustained, and the action hereinafter described occurs in place of the action described in the paragraph immediately preceding.

Weight 2, responsive to the continued force of setback and freed from sleeve 3 by the inward motion of ball 6, moves rearwardlyagainst the pressure of spring 5, carrying ball B with it as shown in Figure 3. If the setback is sufficiently sustained, the slope of hole 2c causes ball 6to move outwardly into hole 3c because of setback force on ball 6. When setback has ceased, springs 4 and 5 tend to return weights I and 2, respectively, to their original positions. Sloping shoulder Ib of weight I, is used to urge ball outwardly so that it occupies a position with slightly more than half its diameter in hole 2c of weight 2 and slightly less than half its diameter in hole 3c of sleeve 3 if it has failed to enter this position due to the force of setback. Thus ball 6 locks weight 2 in the retracted position in regard to sleeve 3, as shown in Figure 4.

At the end of setback, the device is thus in the condition shown in Figure 4. Weight l has assumed its original position in respect to weight 2. Weight 2 has moved and is locked rearwardly with respect to sleeve 3. Consequently both weight I and weight 2 are contained within sleeve 3.

In some applic-ations, it is desirable that Weight 2 be expelled from sleeve 3 after the cessation of setback forces. In this condition, lip 3a is omitted from sleeve 3, and shoulder 2b may be omitted from weight 2. Ball 6 may then roll outwardly from weight 2 and sleeve 3, so that spring 4 expels weight 2 from sleeve 3 when setback has ceased.

When the device is used to block motion of a powder train interrupter or similar mechanism such mechanism is blocked by the forward portion of weight 2, and is not free to move to its armed position until the action described has taken place as shown in Figure 1, and the device has assumed the position shown in Figure 2.

I claim:

'I'he combination with a fuse for ordnance missiles of means forming an axial bore in said fuse, a firing pin positioned within said bore, means forming a transverse bore within said fuse, a plastic element slidable within said transverse bore and adapted to accommodate a detonator, resilient means adapted to bias said plastic element into normal armed position to align said ring pin with said detonator, means forming a longitudinal bore in said plastic element, safety set back release mechanism within said latter bore to compress said resilient means for latching said plastic element intounarmed position, said safety set Vback release mechanism comprising, a rst -cylinder stationary within said latter bore, a second cylinder slidable within said first cylinder and spring biased forwardly to extend in a forward direction a substantial distance from the forward end of said first cylinder, means to latch said rst and second cylinders together to prevent axial movement, a third cylindrical Weight slidable within said second cylinder and spring biased in a forward direction to place the forward end of said weight in substantial alignment with the forward end of said second cylinder, slot means in said fuse for accommodating the forwardly extending portions of said second cylinder and said Weight, said Weight being constructed and arranged upon sustained set back to release said means latching said first and second cylinders whereby said second cylinder is forced rearwardly and out of said slot means by sustained set back due to launching acceleration to release said plastic element and to enable said resilient means to move said element into armed position.

JACOB RABINOVV.A

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,549,763 Greenwell Aug. 18, 1925 1,690,331 Brayton Nov. 6, 1928 FOREIGN PATENTS Number Country Date 558,570 Great Britain Jan. 11, 1944 690,879 France June 30, 1930

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