US3034425A - Hydraulic presses - Google Patents

Description

May 15, 1962 w. HuEm-:R 3,034,425

HYDRAULIC PRESSES Filed Feb. ll, 1959 3 Sheets-Sheet l May 15, 1962 w. HUETTER 3,034,425

HYDRAULIC' PRESSES Filed Feb. l1, 1959 3 Sheets-Sheet 2 FIG. 4

[NVE N mi? will fre/'mfp A TTRNE YS May 15, 1962 w. HUETTER HYDRAULIC PRESSES 3 Sheets-Sheet 3 Filed Feb. l1, 1959 IIIIIFI. Il

Mge/bm 'iinited States Patent dice 3,634,425 iatented May l5, 1952 3,034,425 HYDRAULIC PRESSES Will Huetter, Krefeld, Germany, assignor to Herbert van Huellen and Alfred van Huellen, trading as the iirm Niederrheinische Maschinenfabrik Becker & van Hucllen Filed Feb. 11, 1959, Ser. No. 792,553

Claims priority, application Germany Feb. 22, 1958 3 Claims. (Cl. 10D-214) The invention concerns a hydraulic press which has a conventional stationary bedplate and a press table capable of being lifted and lowered. A single controlled hydraulic working cylinder adapted to engage the center of the press table may suiiice for the movement thereof. Usually, however, several hydraulic working cylinders are disposed as symmetrically as possible about the center of the press table.

Apart from the exceptional case which is only possible with multi-cylinder presses where, as is known, owing to a non-uniform impact of the hydraulic working cylinder the press table may be brought into a position inclined to the bedplate during the working stroke, the press table is normally moved in planes parallel to the bedplate. In order to secure it moreover against undesired tilting out of this position, the press table is usually guided with its side surfaces or corners on corresponding upright counter-surfaces of the press frame. These fail, however, if the press table assumes, for any reason at all, an inclined position relative to the bedplate during the working stroke. The press table can easily jam in guides of this kind which leads at least to disruptions of this operation, as a rule even to severe damage of the press. An unintentional inclined condition of the press table relative to the bedplate occurs for example when the material being pressed has a non-uniform thickness, its upper surface being therefore inclined to its lower surface.

An object of the present inventionis to provide a presstable guide which, on the one hand, safeguards the press table during its working and idle strokes against excessive tilting out of its plane-parallel condition relative to the bedplate and, lon the other hand permits an inclined position of the press table relative to the bedplate Without danger of jamming.

Another object of the invention is to provide a press which is simple and reliable in operation, with a further aim of constructing the press-table guide in such a way that it exerts on the press table, if the latter assumes an inclined position, a restoring force for bringing it back into a plane parallel to the bedplate.

According to the present invention a hydraulic press comprises a'stationary bedplate and a press table, the latter being movable by means of a plurality of controlled hydraulic working cylinders either in a plane parallel to the bedplate or in an inclined condition relative thereto, the press table carrying at least one guide rod of such length and construction that its free end extends for a suiiicient distance beyond the press table to a stationary press part and is adapted to bias the press table towards a parallel position relative to the bedplate whilst being elastically yielding it permits an inclined position :of the press table relative to the bedplate. A slide bearing accommodates the guide rod so that its axis is exactly perpendicular to the bedplate in the plane-parallel position of the press table.

The invention will be described further, by Way of example, with reference to the accompanying drawing, in which: Y

FIGS. l and 2 are vertical sections through a hydraulic press in different positions of the press table relative to the bedplate, these views being taken on the line I-I of FIG. 3;

FIG. 3 is a horizontal section through the press taken on the line III-III of FIG. l;

FIGS. 4 and 5 are vertical sections, similar to FIGS. 1 and 2, through a hydraulic press of modied construction, taken on the line IV-IV of FIG. 6; and

FIG. 6 is a horizontal section through the press taken on the line VI-VI of FIG. 4.

In both embodiments a press cross beam 2 is rigidly disposed on a stationary press frame 1; a vertically movable press table 3 is operated by a controlled hydraulic Working cylinder 4. Guide rods 5 are iixed to the press table 3 and their `slide bearings 6 are disposed on a stationary press part namely the bedplate 2v (FIGS. l, 2) or the press frame 1 (FIGS. 4-6). The slide bearing 6, which in the plane parallel position of the press table 3 has its axis perpendicular to the bedplate 2 above or beneath a xing point 7 of the associated guide rod 5 on the press table 3, has a convex inner surface 6a (exaggerated in the drawing) which denes a passage Whose width equals that of the'associated rod 5 at the center of this passage and progressively increases towards both ends thereof. The guide bars 5 are free from stress only if the press table moves in plane-parallel position relative to the bedplate 2. Thus the guide bars 5 try -to retain the press table 3 in the plane-parallel condition or to return it into this condition.

If, however, for `any reason at all the press table 3 should perform a Working stroke in the inclined condition relative to the bedplate 2 (FIGS. 2 and 5), the or each guide bar 5 must yield since its fixing point 7 on the press table in the inclined position thereof -moves out towards one or other direction relative to the associated slide bearing 6. Having regard to the maximum inclined position of the press table 3 and the maximum pressure force exertedby each Working cylinder `4, the guide bar 5 can be so constructed that, especially by appropriate dimensioning of its cross section, on the one hand it exerts on the press table a suliicient restoring force into the plane-parallel position relative to the bedplate 2 and, on the other hand, it permits, without excessive resistance against iiexure, an inclined positioning .of the press table 3 relative to the bedplate 2.

The embodiment shown in lFIGS. l to 3 has a substantially rectangular press table 3 which, at each of two sides on which no charging or unloading of 'the press occurs, is provided with a rigidly arranged projection 8. rl'.o each projection 8, which preferably can be formed as a lug cast onto the press table 3 or welded on to it, there is rigid-ly fastened at 7 the upwardly extending guide rod 5 which with its free end extends into the slide bearing 6 rigidly disposed on the bedplate 2. The guide rod 5 and the slide bearing `6 are thus `disposed outside the Ipress space and do not hinder the charging yand unloading of the press or the pressing .operation itself. If the press table 3 is disposed in a plane-parallel position relative to the bedplate 2 .(FIG. l), each slide bearing 6 has its axis truly perpendicular to the table above the fixing point 7 of the associated guide rod 5.

In the embodiment shown in FIGS. 4 to 6, in contradistinction to the rst embodiment shown in FIGS. l to 3, the press table 3 carries a ldepending centrally disposed `guide :bar 5, the slide lbearing `6 of this rod being xed in a housing 6b to the press frame 1. The slide bearing can also be provided several Vguide rods lying symmetrically relative to this intersection. For example, two guide rods may be arranged in either or both planes 10 and 11.

If the press table 3 performs a working stroke and therefore is moved in the direction towards the bedplate 2 in the first embodiment, the stressed length of lthe guide rod 5 is shortened between the points 7 Y and 6', whilst in the second embodiment it is increased. With this the flexural resistance of the guide rod is increased in the first case and reduced inthe second case. This bar can if necessary, according to known `rules of mechanics, he `formed in such a way that its exural resistance remains approximately the same whereby the restoring force exerted by it on the press table 3, uging it from the inclined position into the plane-parallel position relative to the fbedplate Y2, also remains constant within the tlimits in which its stressed-length changes during a working stroke lof the press table.

Conveniently either the internally curved slide bearing 6 inrits housing 6b, or the housing itself, can be pivotably mounted on the associated press part.

l. VIn a press, in combination, a stationary structure including a frame and a bedplate fixed to said frame, a tiltable table displacea-ble on said frame toward and Vaway from -said bedplate, power means engaging said frame and'said table for reciprocating the latter relatively to said bedplate, a normally straight guide rod of limited bearing having convex internal wall-s Vforming a passage of a Width equaling that of said rod at an intermediate cross section, the width of said passage increasing progressively from said intermediate cross section toward its ends.

2. In a power press, in combination, a stationary structure including a frame and a bedplate fixed to said frame,

a tiltable table ldisplaceable on said frame toward and away from said bedplate, fluid-operated means engaging said frame and said table for reciprocating the latter relatively to said bedplate, a normally straight guide rod of limited resilient deformability extending generally in the direction of reciprocation of said table, Va mounting rigidly securing an extremity of said yrod to said table, a bearing for said rod secured to-'said structure at a location spaced from said mounting but kaligned therewith in the direction of reciprocation of said table, said table and said -bedplate having confronting work-engaging surfaces normally parallel to each other and perpendicular to said resilient deformability extending generally in the direction of reciprocation of said table, a mountingk rigidly securing a first part ofsaid rod to said table, and a bearing for a second part :of `sadrod secured to said structure at a loca-tion spaced from said mounting but aligned therewith Vin the direction of -reciprocation of said table, saidV table and ysaid bedplate having confronting workengaging surfaces normally parallel to each other and perpendicular to said direction of reciprocation, said bearing engaging said rod along a single narrow peripheral zone of the latter while enabling limited llexural deformation of said rod in response to a tilting of said table by said power means upon the engagementV of a workpiece with beveled sides by said confronting surfaces, said direction of reciproca'tion, said bearing having convex internal walls forming a passage of a width equaling that of said rod at an intermediate cross section, the width of said passage increasing progressively and substantially symmetrically from said intnermediate cross sectionV toward its ends whereby `said bearing engages said rod along a single narrow peripheral zone of the latter while enabling limited iiexural deformation of said rod in response to `atilting ofrsaid table by said fluidoperated means upon the engagement .of a workpiece with beveledsides of said confronting surfaces.

, 3. The combination according to claim 2 whereinthe Y axis of said rod in its normal position lies in a median plane of said table, said duid-operated means comprisf ing a pair of hydraulic units bearing upon said table on opposite sides of said median plane.

References Cited in Vthe tile of this patent UNITED STATES PATENTS

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