US2640386A - Shell loading device - Google Patents

Description

June 2, 1953 R. c. ROLLINGS SHELL LOADING DEVICE 2 Sheet s-Sheet l Filed Aug. 22, 1950 INVENTOR.

ROBERT C.ROLLING$ fi/fl 4- ATTORNEYS R. C. ROLLINGS Sl-IELL LOADING DEVICE June 2, 1953 2 Sheets-Sheet 2 Filed Aug. 22, 1950 a INVENTOR.

' ROBERT G.ROLL

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ATTORNE Patented June 2, 1953 SHELL LOADING DEVICE Robert Charles Rollings, New Castle, DeL, as-

signor to E. I. du Pont de Ncmours & Compan Wilmington, DeL, a corporation of Delaware Application August 22, 1950, Serial No. 180,801

((31. lid-) 6 Claims- 1 The present invention relates to a novel method and apparatus for loading non-free flowing plastic materials into containers. More particularly, this invention provides an improved method and apparatus for loading gelatin and semi-gelatin dynamite powders into shells.

Industrial dynamites are made using a variety of explosive compositions, each possessing some particular characteristic or property which makes it more suitable for certain purposes than the other compositions. Most dynamite compositions, after compounding, are in the form of free-flowing powders. A substantial quantity of useful explosive compositions, however, are compounded to form the so-called gelatin and semigelatin powders. An important characteristic of the gelatin and semi-gelatin powders is their cohesion, which enables a user to pack the powders in crevices or against flat surfaces for blasting operations. 1

Free-flowing powders are packaged in paper shells by simply flowing measured amounts of the powder into a preformed cartridge, with or without the aid of tamping means. The gelatin compositions, which do not flow, may efficiently be packaged by forced extrusion through a nozzle into a cartridge. The semi-gelatin compositions, which neither flow nor have the consistency of gelatins, cannot be satisfactorily packaged by either of the above methods. When a semigelatin composition is compressed by a tamping action, it tends to pack solidly due to their inherent cohesive nature and internal friction, thereby blocking the nozzles or passageways of the loading device. When worm extrusion of semi-gelatins is attempted, the powders tend to cake within the worm housing, thus either forcing the worm out, or causing the entire mass to rotate with the worm.

Throughout the present description, the word powder will be used in referring to the explosive composition, whether it be gelatin or semigelatin in nature. This term is so used and widely understood in the explosives industry. The gelatins and semi-gelatins are not powders in the sense of aggregations of ground, loose materials in small solid particles. A gelatin composition is somewhat similar to a putty, while a semi-gelatin may be compared to a wet fine sand, insofar as their flow characteristics are concerned.

An object of the present invention is to provide a method and device for loading non-freeflowing plastic materials into containers. A fur-- ther object is to provide a method and device for loading non-free-fiowing explosive compositions into cartridges. A still further object is to provide a method and device adapted to load either gelatin or semi-gelatin explosive powders in cartridges. An additional object is to provide a method and device adapted to uniformly load a plurality of containers simultaneously with non-free-flowing materials. Additional objects will become apparent as the present invention is further described.

I have found that I achieve the foregoing objects when I first provide a means for confining relatively small amounts of a ncn-free-fiowing material in a hollow cell, eject this confined material into a container by means of pneumatic pressure, and repeat the foregoing cycle a suflicient number of times until the container has been loaded with the desired amount of material. In order to accomplish the foregoing method of loading containers, I have found that a suitable apparatus is one which has a means for properly positioning containers at openings provided in a material reservoir, a means for loading material in said reservoir to a predetermined level, a means for pressing hollow members through the material to the openings in the said reservoir, and a means for applying pneumatic pressure within said hollow members whereby the material entrapped by the hollow members is forced through the openings into the containers. Desirably, the apparatus should also be adapted to repeat the above operations automatically for a suiiicient number of times to load the desired amount of material into the container.

To more fully describe the present invention, reference is made to the accompanying drawings, which disclose an apparatus constructed in accordance with the present invention.

Figure 1 represents a frontal view of a cartridging machine embodying the elements of the present invention;

Figure 2 represents a plan view of the material hopper;

Figure 3 represents a partially sectional View of a portion of the material hopper;

Figure 4 represents an enlarged sectional view of openings in the hopper;

Figure 5 represents an enlarged sectional view of done hollow member and the control chamber; an

Figure 6 represents an enlarged cross-sectional view of the hollow member taken at 6-43 of Figure 5.

In the figures, I is a support base which rigidly 3 supports the vertical support posts 2. Centered by, and rotatable about one of the posts 2 is the shell feeding device 3, operated by mechanical means not illustrated. The shell feeding device 3 contains four shuttle support tables 4 which can be raised or lowered by means of the hydraulic lift 5. On the table 4 above the lift 5 is shown a shuttle Ii containing a plurality of preformed paper shells 7. Directly above the shell feeding device 3 is the material hopper 8,

from the bottom of which project the filling nipples 9. The shells I in the shuttle B. are so positioned as to be in axial alignment with the nozzles 9, and the lift 5 is-adapted to raise the table 4 sufiiciently so that the nozzles 9 enter the open ends of the shells I to a predetermined level.

The hopper 8 is rigidly secured to the posts 2 by means of the support members 22. hopper 8 contains a reservoir 33, the bottom of The which is formed by a nipple plate 26 containing head I3, and adapted to control the vertical reciprocation of the tube head I3 and the rotation of the paddle Hi is the power unit It.

Secured to the hopper 3 in such position that the paddle Iii must pass under it prior to passing over the reservoir is a doctor plate I l, and above the reservoir 30 at the same height as the bottom of the doctor plate I! is a stripper plate 2] containing openings for the passage of the cutters I2,

Leading to the tube head I3 are the compressed air lines It and I9, the lines I8 leading to the annular cut-outs 23 in the tube head I3, and the lines I9 leading to the annular cut-outs 29 of the cutters I2. Within the tube head I3 is the hydraulic fluid pressure chamber 25. Ports, 2% in the tube'head I3. are positioned above the annular cut-outs 23 of the cutters I2, and open to the atmosphere. Flange nuts 3| are at the upper ends of the cutters I2. The airpassageways 32 connect each annular groove 29 of the cutters i2.

Ports 24 lead'from the surfaces of the cutters I2 to passageway 28 which in turn leads tothe material chamber 33. The ports 24 are so positioned that on slight elevation of the cutter I2, within the tube head It, theybecome aligned with the annular cut-outs 23 of the head I3, and the ports 26 are so positioned that on elevation of the cutters I2 in the tube head I3 ;bey ond that required for alignment of ports 24 and cut-outs 23,;they become aligned with the cut-outs 29 of the cutters I2.

'Notshown in the figures are means for controlling the power units It, hydraulic pressure means-for applying pressure in chamber 25, compressed air sources for the lines I8 and I9, and means locking the shell feeding device 3 in-proper position.

In operating in accordance with the present invention, the operators fill the rear portion of the hopper 8 with powder, and load the shut-.

tles 6 with paper shells I having one, end thereof closed, the closed end being at the bottom. The tables 4 are then rotated into position, and, by means of the hydraulic lift 5, the shells- 1] are raised until the nipples 9 extend into the open end of the shells I a preset distance. The power units It are now started, and the loading cycle begins.

Paddle I8 rotates, cutting a chuck of powder from the mass in the hopper 8, and carrying it before it. As the paddle It passes under the doctor plate I'I, excess powder is held back. On continued rotation, an even layer of powder is deposited over the area of the reservoir 30. During this portion of the rotation of the paddle It, the tube head I3 is in its uppermost position As soon as the arm of paddle I0 passes the reservoir 3! the tube head I3 is lowered. Because of the hydraulic pressure in chamber 25 acting on the flanged nut 3|, the tubular cutters. I2 are heldin an extended position with respect to the tube head I3. They remain in this'po'sition as they pass through the layer of powder, thus entrapping a slug of powder within the chamber-33. When the tubular cutters I2 contact the nipples 9, preferably made of a resilient material, their downward motion is arrested. The tube head I3 continues to descend to the'end of its stroke, forcing the cutters I2 back into 'the head I 3. At the bottom of the stroke, the annular grooves 23 and the ports 24 arein alignment, permitting the compressed air fed from line It to enter the interior of the cutters, and force the slug of powder in chambers 33 through the nozzles 9 into the shell I. The tube head It then raises, the'pressure in chamber 25 returns the cutters to the extended position, thereby cutting off the flow of compressed air through the ports 24. Powder caught between the cutters I2 is stripped away by the stripper plate 2| and falls back into the reser- VOll'.

At this point, the paddle II), which has been continuing its rotation, provides a new layer of powder in the reservoir 36, and the cycle is repeated.- The cycle will be repeated for a predetermined number of times, after which the power units It will automatically stop with the tube head I3 in its uppermost position. The operator then lowers the shuttle table 4, separating the filled shells I from the nozzles 9, and rotates the feeding device 3 thus placing a new set of unfilled shells I in position for loading; During the filling ofthe second shuttle of shells, the first set of filled shells have their open ends closed by a separate mechanism mounted on the machine frame. The closed cartridges are then removed from the machine. In setting the automatic mechanisms used in operating the present device, it is not essential that a careful calculation be made of the amount of powder delivered at each stroke. It is only necessary that the strokes be repeated a sufficient number oftimes to completely fill the shells and the nozzles. After the shells have been filled up to the-nozzle, provided excessive air pressure is not used, no'inore powder will pass through thenozzle. 'The resistance of the powder to flow is sufiicientto overcome the air pressure, and the excess powder remains in the chamber 32 until the cutter i2 is raised, at which point the air remaining in the cutter I2 will eject the slug into the reservoir 36. Since the pressures are identical in all cutters I2, and the nozzles 9 are at the same depth in every shell '1, the amount of powder in each shell will be the same. By varying the pressure slightly, the operator can control the stick count, e. g. the

wei ht r. he fill d a i r a Pre sures produce a more densely packed cartridge of greater weight while pressure just suiiicient to force out the slug of powder produces a lightly packed cartridge.

The annular groove 29 on the cutter t2, the exhaust port 2'6 and the air entrance l9 rovide a means for shutting off the device in the event the movement of any cutter I2 is obstructed. Throughout the head It, the portions in alignment with the annular groove 29 are interconnected by passageways 32, so that air pressure applied from line is is present in each space. This pressure is used to balance a hydraulic switch controlling the power units it. If one cutter I2 is unable to descend to the nipple 9 for .7 any reason. it will be forced back in the head sufiiciently to permit. the air in the groove 29 to escape through the port 26, thereby relievingv the pressure in the system, so that the hydraulic switch cuts off the power units 16', stopping the operation. y

For practical operation, it has'been found that hydraulic pressures of from 60 to 80 pounds per square inch are sufficient to insure the passage of the cutters through the layer of powder. At these pressures, the cutting edges of the cutters have a long life, and still seat themselves with sufilcient tightness on the nozzles to prevent appreciable escape of powder into the reservoir rather than through the nozzle. may be varied from to pounds per square inch, depending on the thickness of the layer, the cohesiveness of the powder, and the desired loading density.

Example 1 A semi-gelatin dynamite composition containing 72.6 parts by weight of inorganic oxidizin salts, 18 parts by weight of nitroglycerin, 0.3 part by weight of nitrocellulose, 5.8 parts by Weight of combustibles, and 1.3 parts by weight of sulphur and chalk, was loaded into 1% x 8 inch paper cartridges with the illustrated loading apparatus. Using a hydraulic pressure of about 70 pounds per square inch, and air pressure of about 20 pounds per square inch, a stick count of 122 was obtained. The shells were filled on four loading strokes, the total time for filling operation being about 7 seconds.

The use of pneumatic pressure to eject the powder from the cutters is an essential feature of the present invention. Mechanical tamps acting within the cutters would have to fit closely in order to function at all, and would, therefore, be subject to considerable frictional resistance. Also, the use of pneumatic pressure insures an even distribution of the ejecting force over the mass of material. The cutters of the present invention do not require frequent cleaning, since the air pressure will always remove any residue remaining in the cutter. tioned, the use of air pressures permit the taking of extra strokes to insure the even loading of all shells since powder may remain within the cutter until it is raised from contact with the nipples. Of particular importance in the handling. of explosive material is the safety factor in the present method. Localized high pressure areas are avoided, as is heat caused by friction from closely fitting moving parts. There is no probability of contaminating the powder with lubricants, and any blockage will stop the apparatus before damage can be caused.

The present apparatus can be adapted to load shells of varying lengths by simply changing the Air pressures possesses the additional advantage of eliminating As previously menthe necessity of two types of loading machines for the non-free flowing powders. This feature is very important commercially in eliminating the space and cost. requirements of duplicate devices, each. suitable for only one purpose. In the packaging of gelatins with the present mechanism, it is preferred. to have an inwardly projecting lip on the lower end of the nozzles to insure separation of the powder at that point when the shuttle is lowered.

While the present device is particularly suitable for the packaging of explosive materials, it can easily be adapted for the loading of any nonfree flowing plastic material. The device described is subject to many modifications without departure from the scope of the present invention. The cutters illustrated are in tubular form, many alternate shapes could be used. The cutters are maintained normally in an extended position by hydraulic pressure. Air pressure, or even mechanical spring pressure could be substituted. The control of the ejecting air could readily be altered, for instance, by a valve controlled to coincide with the stroke of the head. The power units and the shell feeding device, neither of which are a part of the present invention, can be replaced with entirely different types mechanisms. The reservoir openings are shown grouped to form a circle, they could be arranged in linear alignment. The rotating paddle could be replaced with a reciprocating scoop.

Therefore, I intend to be limited only by the following claims.

I claim:

1. An improved apparatus for loading into containers a non-free flowing plastic material which comprises in combination, a. reservoir for receiving material, one or more openings at one end of said reservoir, means for positioning the open ends of containers in abutting relationship with said openings outside of the reservoir, means of depositing a layer of material inside said reservoir, hollow members equal in number to the openings adapted to be moved through the said material to an abutting relationship with the said openlugs, and means for applying air under pressure directly to the interior of said hollow members.

2. An improved apparatus for loading gelatin and semi-gelatin explosive compositions into shells, which comprises in combination a reservoir for receiving explosive compositions, a nipple plate at the bottom of said reservoir, one or more downwardly projecting nipples with central apertures in said nipple plate, means for positioning shells under each of said nipples, means for depositing a layer of explosive composition in said reservoir, a plurality of tubular cutting members in axial alignment with said nipples positioned above the said reservoir, means for lowering said plurality of tubular cutting members to abutting relationship with said nipples, and means for applying air under preslsoure directly to the interior of said cutting memers.

3; improved apparatus for loading gelatin and semi-gelatin explosive compositions into shells which comprises in combination, a reservoir, a nipple plate at the bottom thereof, one or more downwardly projecting nipples containing central apertures, means for placing the open ends of shells around said nipples, a paddle adapted to deposit a layer of composition in said reservoir, a cutter tube head adapted to be reciprocated vertically positioned above said reservoir, tubular cutting members mounted in said head equal in number to the filling nipples and with an open end extending downwardly in axial alignment with said nipples, pressure responsive means for holding said cutting members in a normally extended position with respect to said head, means for lowering said head a. distance slightly greater than that required for the said cutting members to contact the nipples, valving means adapted to open a passageway to the interior of the said cutting member for compressed air when the said cutting members are depressed intothe said head, means for providing compressed air to said valving means,

and means for elevating said head.

4. An improved apparatus as claimed in claim 3, wherein the pressure responsive means is a hydraulic fluid chamber filled with hydraulic fluid under pressure.

5. An improved apparatus as claimed in claim 3, including means for repeating the filling cycle automatically for a predetermined number of times without moving the shells.

6. An improved apparatus as claimed in claim 3, wherein the nipples are of a resilient material.

ROBERT CHARLES ROLLINGS.

References Cited in the file of this patent UNITED STATES PATENTS Williams Mar. 18, 1941

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