US2349082A - Press frame construction - Google Patents

Description

y 1944- w. ERNST ET AL 2,349,082

- PRESS FRAME CONSTRUCTION Filed Dec. 11, 1942 Ezra-7", I I3 W INVENT R WALTER 8am? IRA amwvaa, BERNARD D. Mummy-e BY 5% Patented May 16, 1944 PRESS FRAME CONSTRUCTION Walter Ernst, Ira B. Lawyer, and Bernard D. Ashbaugh, Mount Gilead, Ohio, assignors to The Hydraulic Development Corp., Inc., Wilmington, DeL, a corporation of Delaware Application December 11, 1942, Serial No. 468,650

8 Claims.

This invention relates to presses, and particularly to presses that have plates that provide the main structural support.

An object of the invention is to provide a, plate type press that is constructed and arrangedin a manner that the forces applied upon the head and base of the press are assumed directly by the plates that provide the main support structure for the press.

Another object of the invention is to provide a press having plates that are used as the main support members for the head and base of the press, the plates being interconnected in such a manner that they are prevented from substantial deformation when pressing or pull-back forces are developed by the press, whereby the platen of the press can be guided more accurately throughout its stroke of operation.

Still another object of the invention is to provide a press having main supporting plates that carry the head of the press in such a manner that the head is secured in position to the supporting plates with prestressed support members to prevent movement of the head relative to the plates during either the pressing stroke or the pull-back stroke.

It is still a further object of the invention to provide a press having plates that are used as the main frame members that are interconnected in such a manner that the plates are prevented from any substantial bowing to thereby maintain accurate alignment of the movement of the platen of the press during its working stroke.

It is another object of the invention to provide a press using plates as the main frame members wherein the head of the press engages the frame plates so that they absorb the pressing forces and prestressed members are provided between the head and the frame plates which prevent movement of the head relative to the plates during the pull back stroke of the press.

Further objects and advantages will become apparent from the drawing and the following description.

In the drawing:

'Fig. 1 is a front view of a press incorporating features of this invention, a portion of the view being in cross-section.

' Fig. 2 is a side view of the press showing a portion thereof in cross-section.

Fig. 3 is an enlarged cross-sectional view showing the manner in which the head of the press is secured to the frame plate members.

It is well-known in the art that the pressing when the press is on a pressing stroke that the frame plates have a tendency to bow lengthwise of the plates so that the accuracy with which the platen of the press is guided is lost. Also, during the pull-back stroke of the press there is considerable force tending to move the head of the press toward the base until the dies are separated. This is particularly true in deep drawing operations, or in drawing or pressing operations that produce articles that have a relatively large surface area from which one of the dies must be removed during the pull-back stroke. The alternate forces applied to a head of a press thereby tend to constantly move the same relatively to the supporting plates so that difiiculty has been encountered in maintaining the head of the press forces developed in a press tend to separate the head of the press from the base of the press. When using flat plates as main frame members for a press, some difficulty has developed in the operation of the presses due to the fact that true with relation to the plates so that the accuracy of guiding the platen of the press can be maintained, the movement of the supporting plates causing a change in the clearance between the guiding surfaces on the platen and the guide gibs provided on the supporting plates.

The press of this invention consists of a front plate In and a rear plate N that provide the main structural supporting members for the other elements of the press. The plates Ill and II are rectangular in outline and are relatively thick to support the remaining structural elements of the press. The front plate [0 is pro vided with a rectangular opening l2 and the rear plate I I is provided with a similar rectangular opening l3.

The press bed I4 is disposed between the lower ends of the plates I0 and H and is provided with flanges l5 and I6 that engage the bottom edges I1 and I8 of the rectangular openings l2 and I3, respectively, provided in the plates ill and II. The bed I4 is thus supported entirely by the plates l0 and II, and is secured to the plates by means of the bolts l9 and 20.

The head 25 of the press includes a hydraulic motor 35 that includes a cylinder 2| and a piston 22 having a plunger 23 extending therefrom. The plunger 23 carries a platen 24 that is positioned between the gibguides 26 provided adjacent each corner of theplaten 6 to accurately'guide the platen 24 during its stroke of operation. 'The platen 24 is provided with gibs 21 that cooperate with the gib guides 26 for guiding the same.

The head 25 of the press is provided with flanges 28 and 29 that engage the upper edges 3| and 32 of the rectangular openings l2 and [3 provided in the front and rear plates in and I l, respectively. Shoulders 33 and 34 extend upwardly adjacent the flanges 28 and 29, respectively, against which the front and rear plates l0 and II are held by means of the bolts 35 and 36. The bolts 35 and 33 retain the plates i9 and H against the shoulders 33 and 34 toprevent' transverse movement of the plates l and H relatively to the head 25.

To prevent vertical movement of the head 25 of the press relatively to the plates HI and H, a pair of bolts, or rods, 31 extend upwardly from the shoulder 34 adjacent the rear plate I I. These bolts or rods are suitably secured to the shoulders 34 and are disposed a substantial distance apart from one another as shown in Fig. 1. A similar pair of bolts or rods 38 extend upwardly from the shoulder 33 adjacent the front plate H]. A pair of bars 39 and 40 extend between the plates H) and II upon opposite sides of the cylinder 2|, the bars 39 and 40 have their ends thereof positioned upon plates 4| and 42 that are suitably welded to the front and rear plates l8 and II, respectively. The bolts or rods 31 and 38 pass through the ends of the bars 39 and 40 and nuts 43 and 44 are provided on the rods 3'! and 38, respectively, to engage the bars 39 and 40 and thereby retain the same upon the plates 4| and 42, whereby the flanges 28 and 29 on the head 25 of the press are drawn into 5 of the cylinder 2| extending into the reservoir engagement with the upper edges 3| and 32 of v the rectangular openings l2 and 3 provided in the front and rear plates I8 and II, respectively.

During the process of the assembly of the press the rods 3'! and 38 are heated to cause a substantial elongation of the rods. The nuts 43 and 44 are then drawn tightly upon the bars 38 and 48 while the rods 31 and 38 are hot to draw the flanges 28 and 29 against edges 3| and 32 of the openings 2 and I3 in the plates l0 and H. The assembly is thereby tightened while the rods 31 and 38 are hot. When the rods 31 and 38 cool, they shrink and thereby pre-stress the rods 3'! and 38 to the maximum limit of the load they will be required to bear during any operation of the press, whereby the pie-stressed rods 31 and 38 are prevented from elongation during the operation of the press so that the flanges 28 and 29 will always be maintained in tight engagement with the edges 3| and 32 of the openings l2 and I3 in the plates l8 and H respectively.

During the pressing operation the force developed by the hydraulic motor 38 tends to separate the head and the bed M of the press. The upward force upon the head 25 of the press is applied substantially at the middle of the press so that the head 25 tends to bow upwardly whereby the plates l0 and H tend to bow inwardly toward the axis of the plunger 23 between the head 25 and the bed l4 so that the clearance between the gibs 2! and the gib guides 26 is lessened causing a certain amount of unnecessary friction between the gibs 21 and the gib guides 26.

To prevent the plates I8 and II from bowing inwardly in this manner a pair of rods and 46 extend between the plates I8 and H near the upper edges thereof. The rods 45 and 46 extend through bosses 41 and 48, respectively, provided on opposite sides of the cylinder 2| of the hydraulic motor 38. Sleeves 49 are provided around the rods 45 and 46 between the bosses 41 and 48 and the plates l0 and H so that when the nuts 58 are drawn tightly against the plates I8 and H they will be securely held between the sleeves 49, and rigidly held from transverse movement by means of the bosses 47 and 48 on the cylinder 2|. The rods 45 thus tie the plates I0 and I together and to the cylinder 2| so that the upper ends of the plates I0 and H cannot bow outwardly when the force developed by the 5| and having a surge valve 53 provided therein which permits a free flow of liquid from the reservoir 5| during the down stroke of the piston 22 until pressure has been created in the upper end of the cylinder 2|, at which time the surge valve 53 closes to permit development of hydraulic pressure in the upper end of the cylinder 2| to complete the pressing operation. Such surge valves are well-known in the art and therefore description of the valve is not necessary.

The reservoir 5| consists of a bottom plate 54 that supports a suitable tank 55.

The apparatus disclosed and described herein provides for a more rigid construction of a plate type press, and increases the accuracy of the press for various operations because distortion of the supporting plates is reduced to a minimum, and the head and bed of the press are accurately maintained in their relative positions between the main frame plates of the press. During the pressing operation of the press the forces tend to separate the head from the bed of the press. Since the entire separating force is borne by the upper and lower edges of the rectangular openings l2 and I3 it may -be seen that the only longitudinal distortion that can occur in the press between the head and the bed is in the plates I8 and II between the upper and lower edges of the openings l2 and I3 in the plates, the head and the bed of the press being prevented from relative movement except through elongation of the plates I0 and H.

When the press has completed its pressing stroke and is ready to return, considerable force develops in separating the dies provided in the press, particularly when the press is used for deep drawing operations, or when the surface area of the article is relatively large even-though the drawing operation may not be exceptionally deep. During the pull-back stroke of the piston 22 the force developed tends to pull the head 25 of the press toward the bed |4, thereby attempting to separate the flanges 28 and 29 from the upper edge of the openings I2 and I3 in the plates l8 and II. However, as previously mentioned the rods 31 and 38 are prestressed to the maxlmum load they are required to carry during the operation of the press, this load being the maximum load developed during the pull-back operation of the press. Since these rods 31 and, 38 are prestressed the head of the press 25 cannot move longitudinally relative to the plates l8 and II so that the flanges 28 and 29 will always be maintained in engagement with the edges 3| and 32 of the openings l2 and I3 in the plates l8 and II, respectively. The construction thereby insures that no play will develop between the various parts of the press. As heretofore referred to the rods 45 prevent the plates from buckling or bowing, from a plane so that the accuracy with which the platen 24 is guided is improved.

While the form of the invention disclosed and described herein constitutes a preferred form, yet it is understood thatthe apparatus is capable of substantial alteration without departing from the spirit of the invention and that all such modifications as fall within the scope of the appended claims are intended to be included herein.

Having thus fully described our invention what we claim as new and desire to secure by Letters Patent is:

1. A press including, a pair of main supporting plates having aligned openings therein, a press head secured between said plates and having flanges engaging said openings in said plates to absorb the pressing thrust of said press, and means for continuously maintaining a unidirectional thrust of said flanges upon the edges of said openings during the complete cycle of operation of the press to prevent relative movement therebetween.

2. A press including, a pair of main supporting plates having aligned openings therein, a press head secured between said plates and having flanges engaging said openings in said plates to absorb the pressing thrust of said press, and mea 1 loaded to at least the maximum force tei to separate said flanges from said openings to continuously maintain a unidirectional thrust of said flanges upon the edges of said openings at all times.

3. A plate type press including, a pair of main support plates having openings therein provided with upper edges, a press head including a hydraulic motor for moving a platen through a pressing stroke and a pull-back stroke, flange means on said head engaging said edges of said openings to cause said opening edges to absorb the thrust produced during the pressing stroke of the hydraulic motor, and preloaded means for maintaining the same direction of thrust of said flanges upon said edges of said openings during the pull-back stroke of said press as occurs during the pressing stroke thereof.

4. A plate type press including, a pair of main support plates having openings therein the upper edges of which are adapted to be engaged by the press head, a press head including a hydraulic motor for moving a platen through a pressing stroke and a pull-back stroke, flange means onsaid head engaging said edges of said openings to cause said openings to absorb the thrust produced during the pressing stroke of the hydraulic motor, means for absorbing the pull-back thrust of said press including means extending between said plates and supported thereby, and means extending between said last mentioned means and said head parallel to said plates to maintain the same direction of thrust of said flange means upon said edges of said openings during the pull-back stroke of the press as occurs during the pressing stroke thereof.

5. A plate type press including, a pair of main support plates having openings therein the upper edges of which are adapted to be engaged by the press head, a press head including a hydraulic motor for moving a platen through a pressing stroke and a pull-back stroke, flange means on said head engaging said edges of said enings to cause said openings to absorb the thrust produced during the pressing stroke of the hydraulic motor, means for absorbing the pull-back thrust of said press including a pair of bars extending between said plates on opposite sides of said hydraulic motor and supported by said plates, and supporting rod means extending between said bars and said head for maintaining positive engagement of said flanges on said head upon said edges of said openings during the pull-back stroke of the press.

6. A plate type press including, a pair of main support plates having openings therein the upper edges of which are adapted to be engaged by the press head, a press head including a hydraulic.

motor for moving a platen through a pressing stroke and a pullback stroke, flange means on said head engaging said edges of said openings to cause said openings to absorb the thrust produced during the pressing stroke of the hydraulic motor, means for absorbing the pull-back thrust of said press including bar means extending between said plates on opposite sides of said hydraulic motor and supported by said plates, and rod means extending between said bar means and said head preloaded to substantially the maximum pull back force developed by the press for maintaining positive engagement of said flanges on said head upon said edges of said openings during the pullback stroke of the press.

'7. A plate type press including, a pair of main support plates havin openings therein provided with upper and lower edges, a press head including a hydraulic motor for moving a platen through a pressing stroke and a pull-back stroke,

flange means on said head engaging said upper edges of said openings to cause said upper edges to absorb the thrust produced during the pressing stroke of the hydraulic motor, preloaded means for maintaining the same direction of thrust of said flanges upon said upper edges of said openings during the pull-back stroke of said press as occurs during the pressing stroke thereof, means securing said press head between said plates adjacent the upper edges of said openings, a press bed secured between said plates adjacent the lower edges of said openings, rigid means extending between said plates above said preloaded means and adjacent the upper edges of the plates for interconnecting said plates, and means securing said rigid means to said head whereby said rigid means, said head and said bed prevent any substantial deflection of said plates.

8. A plate type press including, a pair of main support plates having openings therein provided with upper and lower edges, a press head including a hydraulic motor for moving a platen through a pressing stroke and a pull-back stroke, flange means on said head engaging said upper edges of said openings to cause said upper edges to absorb the thrust produced during the pressing stroke of the hydraulic motor, preloaded means for maintaining th same direction of thrust of said flanges upon said upper edges of said openings during the pull-back stroke of said press as occurs during the pressing stroke thereof, means securing said press head between said plates adjacent the upper edges of said openings, a press bed secured between said plates adjacent the lower edges of said openings, said hydraulic motor in said head extending upwardly therefrom between said plates, and rigid means disposed above said preloaded means extending between said motor on opposite sides thereof and the upper edges of said plates to rigidly interconnect said motor and said plates, whereby said rigid means, said head,

said motor and said bed prevent any substantial deflection of said plates.

WALTER ERNST. IRA B. LAWYER. BERNARD D. ASHBAUGH.

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