US2280471A - Apparatus employed in the hardening and tempering of armor-piercing projectiles and the like - Google Patents

Description

April 21, 1942.

w; BRIDGES ETAL 2,280,471 APPARATUS. EMPLOYED IN THE HARDENIQG AND TEMPERING 0F ARMOR-PIERCING PROJECTILES AND THE LIKE Filed Feb. 11, 1941 him/v5 Patented Apr. 21, 1942 iTED orrice I APPARATUS EMPLOYED IN THE HARDEN- ING AND TEIVLPERING OF ARMOR-PIERC- ING PROJECTILES AND THE LIKE Application February 11, 1941, Serial No. 378,478 in Great Britain December 30, 1939 3 Claims.

This invention is for improvements in and relating to apparatus employed in the hardening and tempering of armor piercing projectiles and the like. In the hardening and tempering process for armor piercing projectiles it is necessary at certain stages to submit the projectiles to a pro-heating operation. In the methods at present in use the projectiles are pro-heated one by one and in this operation are subjected to direct contact with a heating flame. procedure has two disadvantages. The first is due to the treatment of the shells one after another and resides in a low output and uneven results, and the second resides in the oxidation of the surfaces of the projectiles by reason of the bare flame. The present invention provides in the hardening and tempering of armor piercing shells the step of pre-heating the shell by subjecting them to an atmosphere of hot air or gas. This indirect mode of heating, as contrasted with the hitherto-practised mode of heating by direct flame contact, gives more even results and it reduces the oxidation of the shell 1 surfaces, particularly if the atmosphere is a nonoxidising one, such as may be obtained by the employment of an inert gas or an atmosphere deprived of, or low in, oxygen.

According to a further feature of this invention there is provided in or for a furnace for the heat treatment of metal articles, particularly for the pro-heating of armor piercing shells, a device for supporting the articles during treatment, comprising a receptacle having a plurality of abutments at different levels and carriers, for the articles, adapted to be received on the abutments one above the other in a tier and to be inserted and removed one after another through the top of the receptacle, wherein the arrangement is such that each carrier in its'movement to or from its rest position clears all abutments located at a higher level. To this end the relative dimensions and/or configuration of the car-. riers and their respective abutments may differ in such manner that each carrier is capable of being supported only at one predetermined level.

The above device permits a plurality of shells or the like to be treated in the furnace at the same time, particularly if, as is preferred, each carrier receives a plurality of the shells or the like. By treating the said work-pieces in batches as thus provided for, not only is a greater uniformity in the heat treatment achieved and testing or checking simplified, but the output of the plant is increased.

In order that the invention may be better un- This mode of derstood reference will now be made to the accompanying drawing, in which Figure 1 is a sectional elevation of a device constructed in accordance with the present invention, for use in conjunction with an electric furnace (not illustrated) in the pre-heating of armor piercing shells at one or more stages in the hardening and tempering thereof;

Figure 2 is a plan, showing in one half thereof the upper end of the device and, in the other half thereof, a carrier located in the device; while Figures 3 and 4 are views similar to Figs. 1 and 2, but illustrating a device for holding a lesser number of heavier projectiles.

In the accompanying drawing, the electric furnace itself (of the heated air type) is not illustrated, since those versed in the art to which this invention relates will appreciate that the furnace may be wholly or in the main of known construction, approximately in the form of a vertical cylinder, and that the body of the device herein illustrated and described may be built into the furnace or may be constructed as a separate entity to be inserted therein.

The device comprises a plurality of vertical guide bars 3! spaced apart around its circumference by suitable peripheral connections, these guide bars being for example four in number. They are advantageously of T-section material having the central webs 3la. directed radially inwards. At various levels in the height of this device or the furnace incorporating it abutments 32 are provided in association with these webs 31a, on which abutments carriers 33 hereinafter described in detail may rest. There maybe abutments at as many levels as circumstances require. Thus in Fig. 1, abutments are provided at four levels, while in Fig 3 abutments(32a32c) are provided at three levels because the device shown in Fig. 3 is intended to deal with longer projectiles. Referring to Fig. l, the abutments 32a, 32b and 320 (below the top abutment 32d) comprise small blocks of metal attached one at each side of each web Sla, and the top abutment 32d may either consist of such blocks or may be constituted by the flanges of the T-section members 3|. The abutments differ progressively in size from the top level to the bottom one, so that the abutments at-the top level project to the least extent at the interior of the furnace, while those at the bottom level project to the greatest extent, and those at the intermediate levels project to intermediate extents. It will therefore be appreciated that a carrier 33a. for the bottom level, provided with parts so disposed as to rest on the abutments 32a of said bottom level, may readily be so constructed that, in being lowered into the furnace or retracted from it through the top, it clears the abutments at all the higher levels. The same is true of the carriers for the intermediate levels.

Each carrier 33 is a metal element, substantially flat in form but ribbed as desired for strength, and having at spaced locations in its' periphery radial slots 34 in which the flanges Bio, of the vertical bars 3| aforesaid may be received. These flanges 3la co-operating with the slots 34, therefore serve as guides for a carrier as it is being lowered into and withdrawn from the furnace. In the several carriers, however, the material thereof at each side of the slots extends outwards to contrasting distances from the centre of the carrier. These dimensions are so chosen with regard to the degree of inward projection of the abutments that, for example, the bottom carrier 33a is capable of sliding down the guide bars past all the abutments 32d, 32c and 3212 until it comes to rest on the abutments 32a on the bottom level. Likewise each intermediate carrier is capable of sliding down past all abutments above those of the level at which it is intended to be located, while the top carrier 33d is capable of resting on the abutments 32d of the top level and is not capable of descent past these abutments.

It will be appreciated that it is the material of a carrier 33 at each side of the aforesaid slots 34 in said carrier that rests upon the appropriate abutments.

In the case of armor piercing shells the said shells are preferably suspended from the underside of the carriers as indicated at I4 and I4 in Figs. 1 and 2 and 3 and 4 respectively. For this purpose each carrier may be provided with tapped holes 35 at suitably spaced locations and into-each hole a screw-threaded projection suitably attached to a shell at the rear end thereof may be screwed so that the shells are suspended nose downwards from the carriers. Each carrier may be arranged to aclcommodate any convenient number of shells according to their size and the diameter of the furnace. Thus a given furnace may be provided with alternative sets of carriers. For example there may be one set of carriers each of which is adapted to accommodate four shells and another set each of which is adapted to accommodate eight smaller shells.

In order to facilitate the lowering of the carriers into, and their removal, from the furnace through the upper end thereof, each carrier may be provided with a central screw-threaded hole 36 into which a lifting ring 31 may be screwed.

For the purpose of achieving uniformity of heating throughout the furnace the latter may be provided with a plurality of pyrometers at different levels. For example there may be one pyrometer near the base of the furnace and another pyrometer near the top thereof.

We claim:

1. In furnace apparatus, means for receiving and supporting articles, comprising a cage-like structure having a plurality of spaced vertical perimeterically disposed guide bars providing an unobstructed space Within them; a series of vertically spaced abutments on each of said bars disposed to provide a plurality of horizontal sets,

a horizontal dimension of the abutments in each set increasing progressively from the uppermost set to the lowermost; and an article carrier engageable with each horizontal set of abutments to span the space within the vertical guide bars and support the articles therein, each carrier having perimetric apertures to slidably engage portions of said vertical guide bars, and the position of the abutment engaging portions of each carrier varying, whereby each carrier is engageable only with a predetermined horizontal set of abutments to be supported thereby, and may freely slide along said guide bars during introduction into and removal from the structure through the top thereof, clearing all abutments above its own particular set.

2. In furnace apparatus, means for receiving and supporting articles, comprising a cage-like structure having a plurality of parallel vertical guide bars spaced around its perimeter, providing an unobstructed space within them; abutments on said bars disposed to provide a plurality of vertically spaced horizontal sets, the abutments of each set projecting inwardly of the bars to progressively increasing extents from the topmost set-downwards; and a plurality of article carriers, one for each set of abutments, for spanning the space within the guide bars and supporting the articles therein, said carriers having perimetrically disposed guide apertures for slidable engagement with the guide bars and portions adjacent thereto engageable with the abutments, said portions on each carrier being disposed at a radial distance from its axis which is different from the corresponding distances on all other carriers, whereby each carrier is engage-

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