US2005260A - Press mechanism - Google Patents

Description

June 18,1935 HLIYYETT 2,005,260

BRES S MEC-HANI SM 2 Sheets-Sheet 1 Filed Dec. 30, 1952 June 18, l935.- I up. HUYETT 5 PRESS MECHANISM Filed Dec. 50, 1952' 2 Sheets-Sheet 2 Patented Jzme' 18,1935,

omrrn STATE AT NT I t v I rrmss MECHANISM Daniel D. Huyett, Wilmington, -Del., assignor to Atlas Powder Company, Wilmington, Deli, 2. corporation of Delaware, Application December 30', 1932, Serial No. 649,622

- .14 Claims. (c1. 86-20) This invention relates to press mechanism and more particularly to what may be termed a multiple point uniform pressure press adapted to deliver uniform pressure upon material at a multiplicity of points.

The press-of-the present invention is of par-.

ticular utility in pressing explosive charges into detonator or blasting cap shells, but as this description proceeds it will be seen that the invention isnot limited with respect to the particular" use for which the device is employed but that it is'capable of use in a wide variety of pressing and pelleting operations.

Uniformity is particularly desirable in the manufacture of many pelleted articles and espe-' cially in the manufacture of explosive charges. It is customary in, the manufacture of detonators to deposit the explosive'chargeused into a large 7 number of det'onator shells in asingle operation and then remove the rackbontaining the charged shells to. a-press where pressure is applied.simul-= taneously to all .of the chargesby means of numerous metal press points .or' plungers one of which enters the open end ofeacli shell.

' It is very diflicult to deposit uniform weight charges into detonator shells within the limits of commercial practice because of'variationsin the. density of the explosive and variation in its flowing properties. Consequentlmflthe under-weight charges are under pressed 'while over weight charges are over pressed. Over pressing. may render the charges dead. pressed or causebulging of the detonatorshells. Upon the other hand ,under pressed charges are conduciveto; even greater evilsfor where the the explosive charge it not firmly pressed into. a common mass, it

tends to-loosen and fall out of the open endof u the shell. The presence of loose explosive in the, metal containers in which the shells are packed n tu e a x ed n l .e eatha ar u t e ev e t to se' de o tor from whi h he explosive is wholly orpartly missingbrin'gs about s-fir lt-is, thereforeia primary ob] i v ntion o .b n ab utu ty e fiw upon the ub an e ne, re sed -.wl. .-.at same time. maintainin conditions sa e y for. the pre s operators,

ur h objects and d a t s ofibe tion will be rset, forth in the detailed description 3 which, q ws the a cq n draw ng .laay w. .29?! 2%.

. Figure 1 is a sectional "of Fig. 2.

urel2, 'the. diaphragm I {may beheld at fi mtermediate; steel coverapla-te; may

. sure pre s po nt 8 Figure 2 is a vertical sectional view upon line 2-2 of Fig. 1.

Figure 3 is a vertical sectional view illustrating a modified form of the invention, in which the cushioning and pressure applying means is car-- ried by the bed plate of the press instead of being carried by the gate or head'of the press as in Figures 1' and .2, and.

Figures 4 and 5 illustrate further. modified forms of the diaphragms hereinafter described.

Like numerals designate corresponding parts in all the figures of the drawings.

In the form of the inventionillustrated in' Fig ures 1 and 2,, 5 designates the'vertically reciprocatory gate or hea d of the is fastened to the gateby bolts 1, and a block 8 is secured to plate-6-by screws 9. The plate 6 is provided with a multiplicity of openings l0 shaped to receive the plungers comprising shanks p'ress. Asteel plateB II and enlarged heads ,l2. The tops of these heads are properly rounded and. highly polished and areall acted upon .by a single rubber diaphragm l4 common toallpoints. This diaphragm ismadelof non-coldfiowrubber whichhas the.

after being subjected to pressure. It will not flow or take permanent set under repeated.

characteristic 'of recovering its original thickness strain as readily as some grades of rubber, .These non-coldflow. properties are securedby definite'methods of compounding and curing and by proper moulding. Underactual testa di'aphragm of this character with. 1500 pounds per} square inch hydraulic .p'r'essureimposed has been subjected to 1,728,000' strokes of ,the..plunge'rs r without failure of. the, rubber. This'is equivialent to 2160 days, operation of'the ,detonatori press, AS will .be observed from anjinspection' M directly between gat'e 1:5 am p ate-i5.

ployed, if desired: :J

a mass ported upon press clearance space between the press points and -the openings 23 in block 8 in which said press ited so as to prevent injury to the diaphragm in case the press is operated with insufiicient water pressure in chamber H5, or with other improper adjustments. A slight clearance exists between the bottom' of the plungers and the top of the press points. Thus, as the gate descends and the press points start to apply pressure they have a free lift until the clearance is taken up, after which they exert a pressure on the ex plosive charges 25 in the detonator shells 26 supbed 21 up to the desired maximum for compressing the same to the proper density. Continued downward movement of the gate will result in the lifting of the plungers against the action of diaphragm l4 and against the'action of the constant hydraulic pressure in the chamber 16.

Uniform density in all-detonators whether they contain high, low, or normal charges is assured by adjusting the bottom-stroke position of the press points so that they will travel about one-half. of their total lift when pressing a normal charge. Thus; with a low charge the press points will retract less than half their total lift and with a high charge more than half their total lift, but in all' cases the ultimate pressure delivered upon the charge is determined by the hydraulic pressure existing in chamber I6.

In practice, it is not necessary to provide for a very wide variation in the volume or density of the loose explosive charged into the detonators and therefore a long compensating stroke of the press point is not necessary. A total lift of about has been found to take care of variations met with in the.present methods of charging. However, in designing this press, a lift has been provided and found to be well within the working limits of the rubber diaphragm.

The clearance provided between the plungers D and press points E serves two purposes-it permits the press point to move slightly and feel its way into the mouth of the detonator shell, and it also prevents the transfer of strain to block 8 which might be set up by any slight deflection of plate 6 imposed by the pressure in chamber l6.

With the construction shown in Fig; 2 it will be;

. seen that plate 8 with its complete set of press points can readily be replaced with another, by

removal of four bolts 9, and-without disturbing any of the hydraulic pressure elements. This mounting of a complete set of press points in plate 8 renders it possible to use groups of presspoints of different sizes according to the nature of the work to be done without the necessity .of disturbing the diaphragm and its associated plungers I l. However, I wish it to be understood that a. structure in which the press points are directly connected to the plungers is the scope of the invention. That is to say, it is clear that if the upper' ends of the press points were caused to bear directly against the diaphragm many of the advantages of the present invention would be achieved. Consequently, the appended claims coldfiow character.

'is much less sensitive.

are intended to cover not only the specific. arrangement shown in the drawings, but any equivalent arrangement accomplishing the same general result. The term press points'is to be broadly construed to mean any pressure exerting elements'for simultaneously exerting their individual pressures upon a plurality of elements whether such elements be detonator charges, pellets, or otherwise. v 4

A very close regulation of the finally delivered pressure may be had with the construction herein shown and described because the necessity of packing the individual plungers against high pressures is avoided and they are left free to follow the movements of the diaphragm without excessive frictional interference. Further, any leakage of water or other fluid along the plungers which might find its .way to, and ruin the explosive charge, is effectively prevented.

In the modified form of the invention illustrated in Fig. 3, the plungers I la are shown engaged with a diaphragm l4b which, in this instance, is carried by the bed plate 21a of the press. The press gate 5a carries a steel plate 6a and this plate in turn has the press points I811 rigidly secured thereto by having the heads 24a of said press points bound between the gate 5a and the plate 6a. Under this construction, the plungers Ha are caused to yield downwardly against the action ofthe diaphragm and the pressure in a pressure chamber l6a after the charges in the detonator shells 26a have been compressed to the predetermined degree fixed by the pressure in pressure chamber l6a.

The modified form of diaphragm indicated at Na in Fig. 4 comprises a web of relatively thin (preferably about inch) fiat rubber of the non- In this case, the heads l2 of the plungers are almost flat on. top but are rounded at the corners while the corners of the sockets within which said heads are seated are also slightly rounded as at In.

In the modification illustrated in Fig. 5 the'relatively thin web of non-coldfiow rubber l4 rests upon' the heads 12a of the plungers said heads being rounded across substantially their whole diameters and the upper corners of the sockets, in which said heads are seated being sharp or square.

In the. modification illustrated in Fig. 4, the action is much more sensitive than in the forms illustrated in Figs 1 and 2 but there is some tendency for the diaphragm to wear out because of the chewing action adjacent the upper corner of the heads of the plungers. V

The modification illlustrated in Fig. 5 is much less subject to the wearing action aforesaid and gives much longer wear than the form illustratved in Fig. 4 while giving the desired sensitive action. v

In determining the best form of diaphragm to be employed, I have to'choose between long life upon the one hand and a desired sensitivity'upon the other. The form of diaphragm illustrated in Fig. 2 has a decidedly longer life than either of the diaphragms illustrated in Figsni and 5 but In thisform of diaphragm about 50 pounds perpin is required to deform the rubber "when lifting as against a requirement of only 10 pounds with the diaphragm illustrated in Figs. 4 and 5. In other words, with the hy-- draulic pressure set for the pin to start lifting at any given pressure A the total pressure exerted by each pin as it lifts is approximately as follows with difierent types of diaphragm.-

a Pressure exerted by pin as movement ofpin starts-A Ma" 1111; m" 1m 34" m1;

4+2. A+5# A+10# A+2.5# A+5# A+10# A+12%# A+# A+50# A ten pound variation in total pressure on a charge would benegligible for any known explosive material but 50# variation is considered too great for substances like nitromannite although permissible for fu lminate-chl'orate.

Under. most severe test conditions, the diaphragm of Figures 2 and 3 has shown almost unlimited life, the form illustrated 'in Figure 4 has indicated that it is good for a press operation of about one year, while the form illustrated -in Figure 5 lasts for considerably more than a year.

- Replacing diaphragms more than once per year or even at more frequent intervals is entirely practicable from an operating standpoint. The degree of sensitivity desired is dependent somewhat upon the nature of the material being pressed. For pressing 'fulminate or tetryl I would use the diaphragm illustrated in Figs. 2' and 3 but for material requiring comparatively light only in the making of explosives but in the,

pressures, such as nitromannite, I employ the much thinner diaphragm of Figures 4 and 5.

. The provision of the rubber web 2| for preventing the accidental passage of explosive dust upwardly into the sockets within which the press points are mounted to move is a feature which makes for additional safety to the press operators since it guards against the possibility of explosions arising from the setting on of such explosive dust by either friction or shock in the operation of the press.

The particular character of actuating means for the press gate is immaterial. The press may be either hand or power operated. Presses of this character are very common in the arts not making of pellets, tablets and molding blocks .of the various kinds. The characteristic feature of pressesto which the invention relates is that they com'monly employ a multiplicity of press points and it is in. the provision of simple and eflicient means for equalizing the pressure delivered upon all of the press points that this invention particularly resides, irrespective of the particular character of the material being pressed. v It is to. be understood that the invention is not limited to the precise construction set forth, but that it includes within its purview whatever changes fairly" come within either the terms or the spirit vof'tlzie appended claims. a

Having described my inventio'mwhat I claim is: 1. A device of the character described comprising a press gate, a plate secured thereto, 9. diaphragm held between the plate and gate and shaped to constitute a pressure chamber therebehind, a plurality of plungers having heads engaged with 'said diaphragm, and a. plurality of 3 and a plurality of press points aligned with said plungers.

3. A structure as recited in claim 2'wherein said diaphragm is composed of "non-c'oldfiow rubber.

4. A structure as'recited in claim 2 in combination with a member in which the press points are mounted to move, and a diaphragm of flexible material through which said press points pass and which diaphragm snugly engages said press points.

5. A device of the character described comprising a gate, a plurality of press points fixed rigidly to said gate, a press bed, a diaphragm supported by the press bed having a pressure chamber there-behind, and plungers engaging said diaphragm and aligned with the press points- 6. A device of the character described 'comprising a gate, a plurality of press points fixed rigidly to said gate, a press bed, a diaphragm supported ,bythe press bed having a pressure chamber there-behind, and plungers engaging said diaphragm and aligned with the press points, said plungers being provided with means for limiting their'outward movement toward the press points under the action of said diaphragm.

'7. A machine for applying a uniform pressure containers comprising in combination, a reciprocatory-structure having a pressure chamber formed therein, one side of which pressurechamber consists of a diaphragm, a plurality of press points or punches associated with and carried bodily bysaid reciprocatory member, means for supporting a group of containers in alignment with the press points, said press points being adapted to enter and press the contents of the containers, a-source of positive pressure supply,

means for admitting pressure fiuid 'to the said chamber from said source of pressure supply during the reciprocation of said structure, and means for transmitting the pressure of the diaphragm as determined by the pressure fluid, simultaneously to all of the press points. 8. A structure as recited in claim 7 wherein said diaphragm is composed of a non-cold flow rubber.

9. A device of the character described comprising a reciprocatory press gate, a pressure chamber formed therein, one side of which pres,- sure chamber is constituted by a rubber diaphragm, a plurality of plungers having heads engaged with said diaphragm, and a plurality.

gate to form ,a pressure chamber therebehind,

means forsupporting a group of containers in the line of travel of the reciprocatory press gate, a plurality of press points traveling with the press gate and having ends shaped and dimensioned to enter and press the contents of said containers, means for transmitting the thrust of the said press points simultaneously to the diasimultaneously to the contents of a group of v phragm, and means for admitting pressure fluid to the pressure chamber from asource of pressure supply during the travel of the press gate.

12. In combination, a bodily movable head, comprising a pressure chamber, a flexible, imperforate sheet comprising one side of said chamber, a group of press points bodily movable with s "d head, means for transmitting pressure from said sheet to said press points, and means for admitting, pressure to said pressure chamber from a source of fluid pressure supply during the .movement of said head. 1

13. Means for imparting uniform pressure to a multiplicity of points comprising a reciproca-

Images