US1931902A - Mold making machine - Google Patents

Description

Oct. 24, 1933. OYSTER 1,931,902

I MOLD MAKING MACHINE Filed Oct. 6, 1950 2 Sheets-Sheet 1 /4 la flr w li t INVENTOR. 9 0 8850/2 5. 0 yaler Oct. 24, 1933.

E. F. OYSTER MOLD MAKING MACHINE Filed Oct. 6, 1930 2 Sheets-Sheet 2 INVENTOR.

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Patented Got. 24, 1933 UNETED. STATES Mom) MAKING MACHINE EarlF. Oyster, Shaker Heights, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application October 6, 1930. Serial No. 486,597

Claims.

This invention relates to mold making machines and more particularly to a means for controlling the squeeze and draw operations of such ma-.

Other objects and purposes of the invention will be apparent as the description proceeds. A preferred form embodying the principles of this invention is set forth in the following specifications taken in conjunction with the accompanying drawings, although it will. be uderstood that I do not limit myself to this particular form of mechanism. 7

In the drawings Fig. 1 is a vertical central transverse section on the line 11 of Fig. 2; Fig, 2

. is a diagrammatic plan view showing the position of the control with relation to the other parts of the mechanism; Figs. 3, 4, 5 and 6 illustrate the control means in various positions. 7

Referring now particularly to Figs. 1 and 2, a molding machine is illustrated in somewhat conventional style, including a jolt table 10 having the usual guide'rods 11 at the four corners and having the valve pin 12, which is a principal element of the control means to which this invention pertains, located at the rear and protected by the jolt table;

In the particular type of machine illustrated in Fig. 1 both the squeezing and drawing are accomplished by the same piston. For convenience this 4 will be termed the draw piston, and is indicated by the reference characterlB. A jolt piston 14 of usual construction and forming no part of the present invention is carried within the draw piston. The draw piston 13 is mounted Within a casing 15, which provides a cylinder within which the piston 13 moves.

A sleeve 16 closes the top of the cylinder 15 and projects down therein as at 17. Thepiston 13 is enlarged at its lower end as at 18, this enannular space 19, which space is limited at the top' by the downward extension 17 of the sleeve 16. The jolt table 10, secured to the upper end I of the jolt piston 14, rests, when not jolting, on'

the upper end of piston 13 so as to move therewith, and the pin 12 is in turn fast to the jolt table. Thus the movements of the pin 12'coincide during all squeeze and draw operations with those of the draw piston 13.

The pin 12 extendsdownward through a valve housing 21, a convenient construction being to have the housing suitably secured at its top to the sleeve 16, as shown.

The pin 12, preferably an integral rod, may con,- veniently take the form of a straight cylindrical 65;, portion 22 for about the upper three-fourths of its length, from which depends a relatively short reduced cylindrical neck 23 below which the pin again gradually tapers outwardly. as at 24 resuming its full diameter and cylindrical form for a 79;

short distance at the bottom end as indicated at 25. The housing 21 throughout its upper portion fits the full portion 22v of the pin closely throughout its upper length. A small annular lubricant.

chamber 26 may be provided near the top. Near the bottom of this close fitting portion an air line 27, exhausting from the draw cylinder as shown at 33, is connected into a chamber 28 disposed near the bottom of the upper portion across the direction of travel of the stem 12, the bottom of' so,

thechamber 28 being formed by a web 28 a port 28 in which fits the valve stem closely so that when any full sectionof the valve stem, as. 22

or 25, is in the web aperture the flow of air will be shut off. l as;

The lower portion 29 of the valvehousing 21 is enlarged to form' anair chamber 30 which is conveniently closed by a bottom plug 31. An

exhaust line 32'to the atmosphereis connected to the chamber 30, preferably near its upper end. 99;

The air line 27, previously mentioned, leads from beneath the head 18 of the. draw piston 13 through a passage 33 in the base of thecasing 15 to the chamber 28. Thus the exhaust path from the draw cylinder to the atmosphere is through 9 5;

the elements 33, 27, 23 28 30 and 32, and eX- haust is possible only when the. portions 23 or 24 of the pin 12 is in the'part 28 Air to raise the draw cylinder 18 is supplied'through a pipe such as 18*"-, of greater capacity than the exhaust line, 190

r for a reason described below. This line is connected to the cylinder at 18 The operation of the apparatus is apparent by a comparison of the positions of pin 12 shown in Figs 1, 3, 4, 5 and 6. Inasmuch as the invention is chiefly operative as an exhaust valve the sequence of operations may be most conveniently. considered in the order of Figs. 3, 4, 5, 6 and 1.

In Fig. 3 the parts are shown in the squeezing 1111i position, the piston. 13 having beenmoved to the upper limitof its travel by means of air pressure which has been admitted by any convenient inlet (not shown) beneath the head 18. This travel has carried the pin 12 upward so that its bottom portion 25 stands above the chamber 28 thus allowing the air beneath the squeeze cylinder to exhaust through the passage 33, line 27 and chamber 28 into the chamber 30 and thence through the passage 32 into the atmosphere. The rate of the supply of air to hold the squeeze cylinder up is greater than the rate of exhaust, so that the action just described will not be effective to allow the draw piston to fall until the operator cuts off the air supply. Upon cutting off the air supply the release of pressure through the path just described allows a quick drop of the squeeze piston of an inch or two to the position of Fig. 4. The utility of this quick short drop is to remove the mold quickly from the pressure head, and will be understood by reference to Figs. 1 and 2 of Patent No. 1,781,126. Supposing the mold of that patent to be in the squeeze position, up against the pressure head as, the jacket 43 will partly surround the pressure head. It is advantageous to have it clear quickly, so that the head 44 can be run back and the operator can turn his attention to removal of the jacket after the draw. This quick drop permits the operators movements to be more eificient.

In Fig. 4 the bottom full diameter portion 25 of the pin 12 cuts off communication between the chambers 28 and 30, thus checking the descent of the piston 13 in the early part of the draw. The length of the portion 25 is so related to the thickness of the web 28 that the descent is not stopped but only checked, because the momentum of the parts carries the valve section 25 below the web 23 so that escape of air is again allowed past the tapered portion 24. As the descent continues the narrowing of the taper allows faster escape of air, as will be apparent from Fig. 5, with consequent increase of speed of the descent. The speed of the draw becomes greatest when the neck 23 is within the aperture of the web 28 but the escape of air is suddenly out oh; by the full portion 22 of the pin 12, holding enough air in the draw cylinder to cushion the piston 13 at the bottom of the stroke, thus completing the draw, with the parts in the position shown in Fig. 1.

It will be understood that theforegoing description, relating to a preferred form of the invention, is illustrative and not limiting, and that the scope of the invention is not to be through which the piston will be moved by the momentum acquired in such early part of the stroke, means for thereafter progressively increasing the open area of said port, and for finally suddenly closing said port near the bottom of the stroke.

2. In a molding machine, in combination, a draw cylinder, an exhaust air valve operatively connected therewith, said valve comprising a pin movable synchronously with said cylinder, an air passage controlled by said pin, said pin comprising portions adapted to completely close said passage and portions intermediate said first named portions adapted to progressively change the effective area or" said passage.

3. In a molding machine, in combination, a draw cylinder, an exhaust air valve for said cylinder, said valve comprising a movable by said cylinder anda port adapted to be completely closed by portions of said pin, said pin comprising a short cylindrical bottom portion, an intermediate portion thereabove of diminishing diameter, a further intermediate portion of reduced constant diameter, and a top cyiindrical portion, said bottom and top cylindricalportions closely fitting said port.

1. In a molding machine, in combination, a draw piston, a valve pin parallel thereto and movable thereby, an exhaust line below saidpiston, an air port in said exhaust line, a portion of said pin being adapted to travel through said port a distance equal to the travel of said piston, the upper and lower ends or" said portion being adapted to completely close said port and the intermediate elements of said portions being adapted to vary the rate of exhaust at successive positions.

5. In a molding machine, a draw cylinder mechanism including in comination means for allowing suddenexhaust or" air beneath said .cylinder, 11162115101 momentarily checking such'exhaust, means for allowing continued exhaust at an increasing rate, means for allowing exhaust at a constant rate, and means for suddenly stopping said exhaust, all in the sequence described.

EARL F. OYSTER.

CERTIFICATE OF CORRECTION.

October 24, 1933.

Patent No. 1, 931, 902.

EARL F. OYSTER.

It is hereby certified that error appears in the printed specification of the above numbered parent requirbig correction as icilcws: Page 2, line 79, claim 1, for "drawn" read draw; anc thaf the said Letters Patent shouid be read with this ccrrection therein that the same may conform to the record of the case in the Patent Office.

Sign d and sealed this 12th day of December, A. D. 1933.

F. M. Hopkins (Seal) Acting Commissioner of Patents.

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