US2195478A - Press - Google Patents

Description

April 2, 1940. J. Y. BLAZEK ET AL 2,195,473

' PRESS I Filed Nov. 24, 1936 2 Sheets-Sheet 1 ATTORNE .9.

April 2, 1940. J BLAZEK r AL 2,195,478

PRESS File d NOV. 24, 1936 2 Sheets-Sheet 2 g VIII/1111a INVEN TOR.

BY fer/r0 Z? Pay wmp gkg Patented Apr. 2, 1940 I John Y. Blazek, Bedford, and Vernen Rf Roy,{

" Cleveland, hio, assignors to Lempco Products,

f Incorporated, Be dford, Ohio, a corporation of Ohio . Application This invention relates to a pressoperated on the same principle as the familiar hydraulic press, in which a fluid acts as the agentjfor transmitting pressure exerted-on it at one'point to the work in the press."

" Hereto-fore presses operated 'under'fluid pressure have been constructed employing a ram which is moved into contact'with the-work and from the work to a position enabling removal "of.

appliesa great pressure thereto. .An objection i to the prior form of construction has been the time required for moving theram from an inactiveposition into contact with the work and, I

again, thetime required for moving the ram the work from the press. A further disadvantage of the types of presses heretofore used has been in the transmission of fluid through the system der.

from the compression cylinders to the ram cylinfluid together with the distance to be traversed bythe same have resulted in unwieldy and 'uneconomical fittings rendered necessary to withstand the pressures involved. With the old type of fluid transmission system leakage, especially 1 at the joints and connections, was very common and equally undesirable.

connecting devices; The time ordinarily idly consumed in move ment of the ram. to and from the work is reduced position, whereupon the work acted on may be It has been an object of our invention-to produce a hydraulic press which wastes less time in idle motion and whioh permits the application of a considerably greater fluid pressure'to the ram than has'heretofore' been deemed possible. We have also designed our invention to, accomplish this in suchIma'nner-that all the fluid ducts are carried in -a single casting which thereby "eliminates the use of many couplings and other by the provision of a dual. pressure applicating deviceyone' portion of which acts-to move the ram into contact with the work rapidly and then becomes inactive while the operating pressure is applied through a second device. A release has been provided for thepressure built up in the ram cylinder which operates to permit the re turn of the ram cylinder rapidly to an inactive i removed from the press.

The fluid, which isordinarily oil, used in the creation and maintenance of the desired oper-':

ating pressure in the ram head is, in accordance with our invention, confined; to ducts formed v.ina casting carrying both the pressure applicating means and the ram cylinder. J

Other objects of ourinvention will "become The extreme pressures developed in the.

November 24, 1936, Serial Na- 112,526 f 1' Claim. (Cl. 1 03-- 11);

apparent from the detailed description following, which is to 'beinterpreted by reference tothe annexed drawings: The novel features of our inventionwill be summarized in, the claim; It

is understoodthat we have only described a preferredform of construction embodying our invention and thatvariations may appear without departing from the. spirit of this invention.

Referring "now .to' the drawings: Fig. 1 is aside elevation of a press embodying our invention; 4 1' Fig. 2 is an} end-view of such a press;

' Fig. 3. ;is' a horizontal section as indicated b the lines 3-3 in Fig;v 1 showing a one-piececon- Y struction of the ram..and pressure cylinders;

Fig. 4 is atransversesection as indicated by the lines 4-4 in Fig. -3 showing' the pressure cylinder check valvesyand the release valve;

Figs. 53 and 6 are tra'n'sversesections asindi' cated bythe lines 5 and. 5-6 in Fig. 3 and showing respectively the'large and small pump cylindersyand 1 v 1 g Fig. 7. is .a' fragmentary section showing the form of gauge used to determine the ram operating pressure. 1 Our invention as hereinafter described contemplates the use ;of \a pair of pump cylinders I4 is provided which may be adjustably positioned onthe 'endzmembers Hlfby movable pins IE to.

provide a table-for the work; This table may be raised'or lowered by means of cables I! secured at one end thereto and-passing over pul-;

leys Hi to be wound, on -a drum carrying a ratchetwheel 2D,to which is' also'secured a hand crank. A suitable pawl 21 enables the table to be raised on rotation ofthe crank .and,-due' to the pawl, will retain the same' in aasuspended position.

.The ram and its-.operating mechanism are. carried by the upper channels l2. -As shown in Fig. '3 a casting- 25 is "carried by said channels and provides anoil r'eservoir 26 open at the .top and for which a suitable cover plate 21 may be provided. r

A ram cylinder 30 is provided in the casting 25..- Carried by the cylinderis the ram the lowermost or work-engaging end of which is removable for repair or replacement. This ram, which snugly occupies the cylinder is provided at its upper end with sealing means 36 which, together with a seal 31 of the bottom of the cylinder, eliminates substantially all loss of oil pressure in the cylinder. Four arms 38 are carried by the casting 25 at top of and about the cylinder 30. Complementaryarms 3 9 are carried by a bracket which is attached to the lower end of the ram 35. Tension springs 40 connect the respective complementary brackets and provide a quick return for the ram head which operatesminates at its inner edge in a. channel 5! which is pivoted at 52: to a pairof downwardly extending ears 58 of the casting 25; The channel 5! carries a pair of'links and 56, towhich are will link 56, but the applied force will be less. For

" parts to position and after this piston becomes stantially identical except as to size.

pivoted the pistons El] and 61 ofthe large and small pump cylinders respectively. The piston lengths and the distances between centers of the links 55 and 56 is such that the difference in piston stroke due to the respective distance of the pump cylinders from the pivot point 52 is cornpensated for. Expressed in another fashion, the pivoted channel 5| mounted at 52 will apply a different arcuate angle of movement and a different force to a piston depending on the distance between the pivot of the channel and the pivot of the links 55 or 56 on the bar; Thus the link 55 will move its cooperating piston farther for a given arcuate movement of thechann'el 5| than this reason the piston adjacent pivot v52 is employed as the high pressure piston and the other is the low pressure piston. Thus the large travel and low pressure of piston 60 rapidly moves the idle the piston 6| operates at high pressure to transmit the small added volume of oil to the parts to apply the operating pressure.

The two pump cylinders and pistons are sub-.

Both pistons are provided at their inner ends with seals which, together with packing adjacent the lower ends of the cylinders eliminates substantially all leakage between therespective pistons and cylinders. I I

In the large cylinder-.45 oil is admitted thereto through the check valve 65 when the ball of the same is drawn inwardly against its spring by creating a partial vacuum in the cylinder. Similarly oil is drawn into the small cylinder 41' through a check valve 65a. A partial vacuum is created by movement of the hand lever5U, which in turn acts to withdraw these pistons from their cylinders.

Upon filling the said cylinders with oil the same is pumped to the ramcylinder through the ducts Bl and 51a in the casting 25. In the course of' travel through said ducts the oil passes a pair of check vaves 68 and 58a which prevent its return to the respective cylinders. These check valves, shown in Figs. 4', 5. and 6,-When pushed against their retaining springs by the fluid"; allow the flow of oil to a common duct H1 leading to the ram cylinder 30. As, the oil is pumped from the cylinder back to the reservoir.

As shown .in

to the cylinder 30 the ram 35 is forced dowh wardly against the springs 40 into contact with the work, whereupon the operating pressure is built up to the desired amount. The large pump cylinder 45 is used principally to rapidly move the ram into contact with the work, after which it becomes substantially inactive. A passage containing a check valve 15, leading to the reservoir 26 through an opening vH5 is shown in Fig. 5. This valve normally acts to prevent flow of oil The coil spring in the same however, is of such strength that when the ram engages the work and begins to build up an operating pressure the valve proper is forced away from the opening by the oil under pressure and thus, makes its escape to the reservoir 2G.

The actual operating pressure, which reaches several tons, is built up by the action of the small piston, during which time the large piston reciprocates idly, If excessive pressureis built up i at the ramhead which might strain the working parts, a-pressure release check valve. 15a,

incorporated as shown in Fig. 6; begins to func-' tion. This valveliia is similar'to the valve '15 just described, except that the operating spring-Tie veryv much stronger and this requires a very much greater pressure acting against the valve iproper to eifect an oil release. As shown in Figs.'5 and I 6, the valve proper of the check valve andql5a are different. The pressure-released by thelarger valve 15 does not attain any considerablemagnitude and withtheordinary'type of valve. results in a continual chattering.

stand so great a pressure that the ball and spring socket construction there necessary. i

It is well to note 'at'this time that the. point at which the large pump-cylinder 45flcuts out,-due

to the action of the check valve 15, may be de- If desired, the springs 40x may be socalibrated that upon a certain extermined in two ways.

tension of the ram.,from*the cylinder they will build up a spring pressure sufficientto o'verbalance the force exerted by the spring ofthe checkv valve 15. If desired, this form of release-need not be used and the pressure set up inthefluid by contact of the ram head with the'work may be utilized to effect such release.

A hand wheel 82, carrying a pin adapted to engage the ball of the check valve is threadingly carried in the casting 25;

Thus rotationof the hand wheel 82 in acounterclockwise direction causes the pin 83 to push the ball 80 away from the outlet which it normally closes and thus permits flow of the 'oil to the'res ervoir' 26. 'When thezramis returned to its 'uppermost position under the action of the springs '45 the pin 83 may be withdrawn, whereupon pressure mayagain be built up in the ram cylinder. To prevent leakage of oil from the reservoir the hand wheel 80 is carried by a tapered bushing 84 shown are rendered On the other hand, the valveproper of the unit file must with which, at its outer end, carries a nut 85 which A forces packing rod 86.

It will be seen from the foregoing description about the hand wheel supporting that we have invented a novel oil-operatedhydraulic press which incorporates many 'distinc-.

tions ,over similar press. mechanism, heretofore built, and especially which" provides a unitary, construction for the "various cylinders and ducts leading thereto, and which provides a ram rapidly movable into ccntactv'vith the Work and back again to an inactive position.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided. the means stated by the following claim orthe equivalent of such stated means be employed;

erable in said cylinders, means for simultaneously operatingsaid pistons, said means comprising a lever pivotally movable about an axis which is normal to a'plane' containing the axes'of said pistons, links pivotally connecting said lever with said pistons, thepoint of pivotal connection of the link connected to the smaller piston beingcloser to the pivotal axis of said lever 'thanfthe link connected to the larger piston, said casting having passages'therein leading from the respective cylinders, a low-pressure relief valve in said lief valve in said small cylinderpassage.

JOHN Y. BLAZEK. VERNON R. ROY.

large cylinder passage and a-high pressure're-

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