US2305601A - Primer assembly and testing apparatus - Google Patents

Description

-- Dec. 22, 194 2.

PRIMER ASSEMBLY ND TESTING Amnmus Filed March 14, "1941 I la INVENTORS Clifford WEmuwn.

John Punch RNEYS c. w. BROWN ETAL 1 Patented Dec. 22, 1942 PRIIVIER ASSEMBLY AND TESTIN APPARATUS i Clifiord W. Brown and John Pouch, Philadelphia, Pa.

Application March 14, 1941, Serial No. 383,456

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 2 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates in general to the assembly of primers for use in ammunition and other related arts, and in particular to an apparatus having features for detecting mis-assemblies.

In previous methods and apparati for assembly of primers, if the percussion element were put in upside down and not detected on inspection, such primer would result in a dud on firing. Similarly a flash hole in the primer head not drilled entirely through to the percussion element chamber would result in a misfire.

In carrying out the invention, advantage is taken of the configuration of the ordinary primer cap, in which the bottom portion has an inward dimple, the under side of the arched primer anvil. This dimple or recession will clear a circuitclosing pin contained in the assembly apparatus but if the primer should be introduced in its inverted position, the pin will yield and close an alarm circuit.

It is, therefore, an object of this invention to produce an apparatus for the assembly of primers which will detect mis-assemblies.

It is a further object of this invention to produce an apparatus for the assembly of primers which will detect inverted percussion elements and incomplete flash holes.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing wherein:

Figure 1 is an elevation in section of a primer assembling apparatus, and

Figures 2 and 3 are elevations in section showing a primer and portions of the assembling apparatus under conditions of faulty assembly.

Figure 4 is a partial plan view of the base showing the stop assembled thereto.

Referring to the drawing by characters of reference there is shown in Figure 1 an assembly unit comprising in the main, a base I, a nest, or primer holder 2 and a stop 3 for quickly positioning the nest concentrically under a punch 4.

In the base I is mounted an electric switch comprising two contact plungers 5 and 6 carried by an insulating plug I screwed into the base. Immediately containing the plungers 5 and 6,

respectively, are the inner metal plugs 8 and 9 which are threaded into a central opening in t e plug 1 and are held apart by an insulating r ng lll. Upper plunger 5 is slidable in a bore in upper metal plug 8 and has an annular shoulder I2 fitted in a countersunk bore it or plug 8 and urged against the inner extremity thereof by a spring i4 acting against a threaded spring holder It iitted in plug 8 and having a bore It for the passage of plunger 5.

hower plug 9 is similarly constructed with an annular shoulder ll in a counterbore l8 and a spring l8 retained by a holder 20 which has a bore 2| for the passage of lower plunger 6.

The circuit, which is normally open between plungers 5 and 6, comprises insulated lead wires 22 and 23 passing through bores 24 and 25 respectively in the base I, a source of current 26 and a signaling device 27, shown in the drawing as a bell, but which may consist of a light bulb, relay or some item of control equipment.

Threaded into the head of upper plunger 5 is a screw 28 and force-fitted into a hole in the head thereof is an insulator 29. Screw 28 serves to fasten the bai'ed terminal 30 of lead wire 22. The insulating plug 29 takes the thrust of another plunger 3! contained within the primer holder 2.

Primer holder 2 comprises a cylindrical block with a central bore 32 and a plunger holder 33 threaded into one end thereof. The plunger holder 33 is generally similar in structure to plunger holders 8 and 9. Plunger 3| has a shoulder 34 fitted in a counterbore 35 of the holder 33 and a spring 36 for pressure against the shoulder 34 is retained by a, threaded plug 31.

The other end of the bore 32 of holder 2 is adapted to receive a primer casing 38, having a flash hole 39 and a curved anvil 4|] within a primer cap 42. Inserted in the top of the primer casmg is a guide 4| for the primer cap 42 and the punch 4 which is shown in the raised position after ramming in the primer cap.

The stop 3 consists of two bars 3a and 3b secured the base by screws and dowels or other convement means, the two bars making a right angle the bisector of which passes through the center of the hole in the base I. It is the function of the stop 3 to conveniently locate the primer holder 2, shown in phantom lines in Fig. 4, in concentric relation to the hole in the base I and the punch 4.

Ina normal assembly, with the primer cap 42 so disposed that the anvil 40 is lowermost in the primer casing 38, no contact is made with plunger 3|, which is received in the recess of the anvil. However, if the primer cap 42 should happen to be inserted into the primer casing in any other than its normal position, for instance upside down as shown in Figur 2, plunger 3| is forced down against spring 36, urging plunger 5 into electrical connection with plunger 6 against the action of their respective retaining springs and the detector circuit is closed. On retraction of the punch 43 and removal of the primer, plungers 34, 5 and 6 are returned to normal position.

Also, in the case of a primer wherein the flash hole has not been completely drilled through, as shown at 44 in Figure 3, plunger 31 will be actuated to complete the warning or remedial circuit.

The particular embodiment shown is for illustrative purposes only. Many other types of electric switches for use in the assembling device will readily suggest themselves to those skilled in the art, and the invention is therefore not to be deemed as limitedexcept within the scope of the appended claims.

We claim:

1. An alarm unit for detecting faults in the assembly of primers comprising a primer casing, a primer cup therein, a flash passage in the casing and an arched anvil in the cup with the hollow of the arch opposed to said flash passage, said unit comprising a holder for reception of the primer casing, a resiliently held plunger in said holder with one end normally lying within said flash passage but terminating short of said arched anvil when the primer cup is correctly seated in said casing, and means responsive to depression of said plunger to produce an alarm signal when the flash hole is incomplete or the cup is in an abnormal position with the hollow of the anvil arch not aligned to receive the plunger.

2. An assembling and detecting device for primers comprising in combination a base block, a primer holding device thereon and positioning means for said primer holding device on said block, an electric signalling device in said block comprising a circuit and two resiliently held conducting plungers in said circuit spaced to hold the circuit open in normal position and with one of said plungers accessible from above said block but terminating at or below the face of the block, insulating means atop said accessible plunger and. a resiliently held plunger in said primer holding device aligned with said insulating means said last-mentioned plunger being receivable in the primer and adapted'to be depressed by the inner parts thereof when the latter are assembled in other than the normal position.

CLIFFORD W. BROWN. JOHN POUCH.

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