US3608478A

US3608478A - High-speed press

Info

Publication number: US3608478A
Application number: US29196A
Authority: US
Inventors: Bernard L Hoffman
Original assignee: Krause Ass F A
Current assignee: FREDERICK A KRAUSE ASSOCIATES Inc; Krause Ass F A
Priority date: 1970-04-16
Filing date: 1970-04-16
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28

Abstract

Press mechanisms comprising a frame mounting at least two pairs of press shoes which are actuated by crankarms; and mechanical or electrical synchronizing means for operating the press shoes in alternate sequence.

Description

United States Patent [50] Field of 100/186, 209, 244, 245, 264, 295, 208, 282; 72/405, 404, 403; 18/30 LM, 30 LC, 30 LD, 30 PM; 83/519 n m H LN 1.2% t mm er BT r o m N m a v P m A 1 1 2 l 7 2 r r [22] Filed [56] References Cited UNITED STATES PATENTS 5/1876 Dederick......................

Apr. 16, 1970 [45] Patented Sept. 28, 1971 [73] Assignee Frederick A. Krause Associates, Inc. Frenchtown, NJ.

X l U 9 p 6 2 1 O 0 [54] HIGHSPEED PRESS Attorney-Ward, McElhannon, Brooks & Fitzpatrick 8 Claims, 4 Drawing Figs.

100/209, ABSTRACT: Press mechanisms comprising a frame mounting 72/403, 100/244, 100/245, 100/282 at least two pairs of press shoes which are actuated by cran- [51] Int. B301) 15/04, karms; and mechanical or electrical synchronizing means for B30b 15/ 14 operating the press shoes in alternate sequence.

PATENTEU SEP28 as?! SHEEI 1 [IF 3 19/ mews S HIGH-SPEED PRESS This invention relates to presses and more particularly it concerns a novel press structure suitable for sustained high production output.

Conventional presses utilize a continuously rotating flywheel which turns a crankarm to move a die shoe in a reciprocal manner back and forth along a linear path. A cooperating stationary die shoe is also mounted along the path and workpiece material to be press worked is fed into the space between the die shoes. As the movable die shoe moves toward, or closes upon the stationary die shoe, the workpiece material between them is squeezed, drawn shaped or similarly worked. Thereafter, as the movable die shoe moves away from the stationary die shoe, the press worked workpiece is removed and a new workpiece is inserted.

The above-described conventional press arrangement is subject to a number of limitations which reduce its effectiveness. One of these limitations lies in the fact that only a very minor portion of each operating cycle is available for doing useful work. The remaining, major portion of each cycle is used in opening the die shoes, in removing the pressed workpiece and in inserting a new workpiece. As a result of this the crankarm length required for a given effective stroke must be quite large. Moreover, as crankarm lengths increase, the resultant local stresses in the system increase at an even greater rate at a given operating speed.

According to the present invention there is provided a novel press arrangement suitable for continuous operation which makes available a much larger portion of the operating cycle for doing useful work. This novel press arrangement moreover actually achieves a reduction in stresses throughout the system by reducing the length of crankarm required to produce a given effective stroke.

The present invention achieves these results through the provision of dual pairs of press shoes arranged to close and open in alternate sequence. These press shoes are guided in a rigid frame for movement toward and away from each other. One press shoe from each pair is connected to be actuated from a common crankarm, so that during one-half of the crankarm rotation one set of the press shoes closes while the other set opens; and during the remaining one-half of the crankarm rotation the first set of press shoes opens while the other set closes. The remaining press shoe in each pair is also arranged to be actuated by a crankarm so that only half the total stroke is undertaken by each individual press shoe. Means are provided for synchronizing the rotational movements of the various crankarms; and these synchronizing means serve to distribute power flow and to equalize stresses throughout the system. As a result higher production speeds may be employed for sustained periods of time without producing undue stresses on the system.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. it is important, therefore that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope the invention.

Specific embodiments of the invention have been chosen for purposes of illustration and description; and are shown in the accompanying drawings forming a part of the specification, wherein:

FIG. 1 is a perspective view illustrating one embodiment of the present invention;

FlG. 2 is a top plan view of the embodiment shown in FIG. 1;

FIG. 3 is a section view taken along lines 3-3 of FIG. 2; and

H6. 4 is a perspective view illustrating a second embodiment ofthe present invention.

As shown in FIG. 1 there is a provided novel double action press which comprises an outer frame 10 of massive boxlike configuration having front and rear sidewalls l2 and 14 and a pair of

end walls

16 and 18. A plurality of

press shoes

20, 22, 24 and 26 are arranged within the outer frame 10 to move reciprocally back and forth therein. The various press shoes are each provided with guide lugs 28 protruding from each side thereof into guide channels 30 formed along the inner surfaces of the front wall and sidewalls l2 and 14.

The first and

second press shoes

20 and 22 constitute a cooperating first pair; and these shoes are arranged with mutually facing work surfaces which move toward and away from each other to produce a desired pressing action therebetween. Similarly, the

remaining press shoes

24 and 26 constitute a second cooperating pair; and these also have a mutually facing working surfaces which close and open with respect to each other to produce a desired press working action. Means (not shown) are provided in order to utilize the press working action of the various press shoes in any desired manner. For example, specially designed cooperating dies may be provided for drawing or stamping sheet metal objects.

A central crankshaft 32 is mounted in the outer frame 10 to extend from a location near the midpoint of the front sidewall 12 to a corresponding location near the midpoint of the rear sidewall 14. Near the center of the central crankshaft 32 there are provided a pair of parallel crankarms 34. As shown in FIG. 2, the outer ends of these crankarms 34 are interconnected by means of a crankpin 36. An inner connecting rod 38 is pivotally connected at one end to the crankpin 36 and is connected at its opposite end via a pivot block 40 to the press shoe 24. Similarly, a bifurcated, outer connecting rod 42 is provided with forked arms 42a and 42b, which are pinned to the crankpin 36 on opposite sides of the inner connecting rod 38. The opposite end of the outer connecting rod 42 is similarly connected via a pivot block 44 to the press shoe 22.

There are also provided

outer crankshafts

46 and 48 which extend from the front sidewall to the rear sidewall 14 parallel to the center crankshaft 32 at a location closer to the

respective end walls

16 and 18. Each of the

outer crankshafts

46 and 48 is provided near the center thereof with a pair of mutually parallel crankarms 50 which are interconnected at their outer ends by means of crankpins 52. A further connecting rod 54 is pivotally connected at one end to each crankpin 52 and is connected at its opposite end via a pivot block 56 to a respective one of the

outermost shoes

20 and 26.

As shown in FIG. 1, one end of the central crankshaft 32 is provided with a crank pulley 60. This crank pulley receives rotative power via a drive belt 62 and a drive pulley 64 from a drive motor 66. It will thus be seen that in operation of the device the central crankshaft 32 turns continuously.

As shown in FIG. 2 the end of the central crankshaft 32 opposite the crank pulley 60 is provided with a central gear 68 which is meshes with

outer gears

70 and 72 keyed to the

outer crankshaft

46 and 48 respectively. It will be noted that

gears

68, 70 and 72 are all of the same size and therefore the

crankshafts

32, 46 and 48 all turn synchronously and at the same speed; although the central crankshaft 32 turns in one direction while the

outer crankshafts

46 and 48 turn in opposite direction.

As shown in H6. 3, the distance between the respective axes of the central crankpin 36 and the central crankshaft 32 is indicated as A. Thus, as the central crankshaft 32 rotates through a complete cycle, the two

press shoes

22 and 24, which are connected to the crankpin 36 via their respective inner and outer connecting

rods

38 and 42, each move laterally, as shown, through a total distance equal to 2A.

Similarly, the crankarms 50 produce displacements B and C between the axes of the

outer crankshafts

46 and 48 and their respective crankpins 53. As a result, when each of the

outer shafts

46 and 48 undergo the complete cycle of rotation, the

press shoes

20 and 26, which are connected to the crankpins 52 by means of associated connecting rods 54, are each caused to undergo a lateral displacement equal to twice the distance B and C respectively as shown.

It will be noted that the

various crankarms

34 and 50 are arranged such that they each extend horizontally at the same time, with the outermost crankarms 50 extending in one direction form the

respective crankshafts

46 and 48 while the crankarms 34 extend in opposite direction from the central crankshaft 32. As a consequence, the first

pair press shoes

20 and 22 are displaced by a minimum distance D as shown in Fig. 3 while the other pair of

press shoes

24 and 26 are displaced by a maximum distance E. As the drive motor 66 turns the

various crankshafts

32, 46 and 48 via the crank pulley 60 and the

gears

68, 70 and 72, the first pair of

press shoes

20 and 22 will move apart from each other, each transversing its respective total displacement 2B and 2A so that the shoes move from a closed displacement D to an opened displacement D+2A+2B. At the same time the second pair of

press shoes

24 and 26 move toward each other, each transversing its respective total displacement 2A and 2C so that the shoes move from an opened displacement E to a closed displacement E--2A2C.

It will be appreciated that as the central crankshaft 32 undergoes one complete revolution, it causes a pressing action during two portions of this invention. That is, during each onehalf revolution one or the other pairs of press shoes are closing upon each other. This contrasts with conventional presses which produce a pressing action only during one portion of shaft rotation. Thus, a grater portion of the movement of the press arrangement is utilized in producing useful work on workpieces.

The synchronizing gears 68, 70 and 72 serve to maintain the two pairs of press shoes 20, 22 and 24, 26 in alternate pressing sequence so that the first pair of

press shoes

20 and 22 close while the

second pair

24 and 26 open and vice versa. As a result of this finished workpiece may be taken out from between on pair of press shoes and new workpiece material may be inserted at the same time that the other pair of press shoes is producing a pressing operation on another workpiece.

In addition to performing the above-described synchronizing action, the synchronizing gears 68, 70 and 72 serve to distribute the stresses undergone by the various moving parts of the system so that a smooth and continuous flow of power may be maintained along with high speed of operation and without the introduction of highly concentrated localized stresses in the system. Thus, it will be appreciated that by virtue of the synchronizing gears the individual crankarms may have a total throw of only one-half of a total stroke of each pair of press shoes. Because of this minimization of crank throw, stresses are considerably reduced and higher speeds are obtainable.

Referring to FIG. 4, a press system similar to that described above, but utilizing an alternate synchronizing will now be described. In the arrangement of FIG. 4, as in the preceding arrangement, there is provided an outer frame having

press shoes

20, 22, 24 and 26 arranged to be driven by central and

outer crankshafts

32, 46 and 48. In the present embodiment, however, no synchronizing gears are provided. Further, no single drive motor and belt/pulley drive system is provided as in the preceding'embodiment. Instead, in the embodiment of FIG. 4 each of the

crankshafts

32, 46 and 48 is driven by an individual synchronous

electrical motor

80, 82 and 84. The

motors

80, 82 and 84 are known as followers" or slaves. Each of these motors receives electrical energy in alternating in current form via

lines

86, 88 and 90 from a common mastersynchro 92. The master-synchro 92 supplies electrical power for driving the

synchronous motors

80, 82 and 84 and further it supplies power in the form of alternating current energy in such a manner that each of the motors is maintained in rotationally synchronized relationship to the master-synchro 92 in a manner similar to the manner in which electrical clock motors turn in synchronization with a master generator at a central power supply system.

It will be seen that the various pairs of press shoes are made to open and close in alternate sequence in the preceding embodiment. Further in the arrangement of FIG. 4 a stress distribution suitable for maintaining an even and continuous flow of power is also provided. However, the power distribution, instead of being effected through mechanical gears, is effected electrically through the synchrosystem.

Having thus described my invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which the invention pertains, after understanding my invention that various changes and modifications may be made therein without departing from the spirit and scope of my invention, as defined by the claims appended thereto. I

What is claimed as new and desired as to be secured by Letters Patent is:

l. A press mechanism comprising a rigid stationary frame, at least two pairs of mutually facing cooperating press shoes, means in said form for guiding the shoes in each pair for movement toward and away from each other, a plurality of crankshafts having crankarms mounted thereon, said crankshafts in turn being mounted to rotate in said frame; means connecting said press shoes to the crankarms of associated crankshafts so as to convert continuous rotational movement of the crankshafts to reciprocal linear movement of the press shoes, and means synchronizing the rotation of the various crankshafts in a manner to cause opening and closing of said press shoes in mutually opposite sequence.

2. A press mechanism as in claim 1 wherein the press shoes in each of said pairs are arranged in said frame to move toward and away from each other during rotational movements of their respective crankshafts.

3. A press mechanism as in claim 2 wherein said press shoes are arranges in a line along the direction of their reciprocal linear movement.

4. A press mechanism as in claim 3 wherein the adjacent press shoes of adjacent pairs are connected to a common crankshaft.

5. A press mechanism as in claim 4 wherein said adjacent press shoes are connected via common crankarms to said common crankshaft.

6. A press mechanism as in claim 5 wherein said crankshafts are gearably interconnected.

7. A press mechanism as in claim 6 wherein one of sai crankshafts is coupled to a press drive motor.

8. A press mechanism as in claim 5 wherein said crankshafts are individually driven by synchronous electric motors.

Claims

1. A press mechanism comprising a rigid stationary frame, at least two pairs of mutually facing cooperating press shoes, means in said frame for guiding the shoes in each pair for movement toward and away from each other, a plurality of crankshafts having crankarms mounted thereon, said crankshafts in turn being mounted to rotate in said frame; means connecting said press shoes to the crankarms of associated crankshafts so as to convert continuous rotational movement of the crankshafts to reciprocal linear movement of the press shoes, and means synchronizing the rotation of the various crankshafts in a manner to cause opening and closing of said press shoes in mutually opposite sequence.

3. A press mechanism as in claim 2 wherein said press shoes are arranged in a line along the direction of their reciprocal linear movement.

7. A press mechanism as in claim 6 wherein one of said crankshafts is coupled to a press drive motor.