US3911718A - Hydraulic ejection device - Google Patents

Abstract

An hydraulic ejector device is presented which is completely independent and normally secured to a special holder or bolster by means of a two piece draw-bolt clamp assembly. The hydraulic quick-disconnects are attached to the two fittings on the holder. The holder is mounted on a movable slide unit or die platen by means of four nuts. The quick-disconnect device is provided so that the self-contained ejector may be quickly changed if the manufacturer desires to use more conventional holders and tooling. The ejector device is generally cylindrical in form and has a central through opening in the casing, in which are found serially from back to front a back plug, a cylindrical pressure chamber in which is a reciprocable piston having a piston extension projecting forwardly, in one embodiment an intermediate or ejector pin normally abutting the piston extension, and a formed-part die at the forward end of the casing, one wall of which is provided by the distal end of the ejector pin in its retracted position. In a second embodiment, the piston extension serves as an ejector pin. In the first embodiment, retraction of said ejector pin and motor is accomplished by the entry of a new part into the die. In the second embodiment, hydraulic fluid is introduced to drive the piston back for a second cycle. These parts in retracted position in the casing provide a sturdy column to transmit forming pressure through the back plug, the piston and the ejector pin to shape a part held in the formed-part die as two platens of a header or press approach each other. Means is then provided for introducing pressure fluid in a cylindrical pressure chamber causing the piston and the ejector pin to move forward and eject the formed part. In the cylindrical pressure chamber, there are substantially equal pressure-exposed areas in opposite directions, one against the back plug and one against the piston, so that when hydraulic fluid is introduced into the pressure chamber to cause an ejection, the entire device tends to remain stationary.

Description

United States Patent [191 Requarth [451 Oct. 14, 1975 HYDRAULIC EJECTION DEVICE Robert E. Requarth, 22 Shawnee Road, Greensburg, Pa. 15601 [22] Filed: June 12, 1974 [21] Appl. No.: 478,689

[76] Inventor:

Primary E.\'aminerC. W. Lanham Assistant ExaminerRobert M. Rogers Attorney, Agent, or FirmBaldwin, Egan, Walling & Fetzer [57] ABSTRACT An hydraulic ejector device is presented which is completely independent and normally secured to a special holder or bolster by means of a two piece draw-bolt clamp assembly. The hydraulic quick-disconnects are attached to the two fittings on the holder. The holder is mounted on a movable slide unit or die platen by means of four nuts. The quick-disconnect device is provided so that the self-contained ejector may be quickly changed if the manufacturer desires to use more conventional holders and tooling. The ejector device is generally cylindrical in form and has a central through opening in the casing, in which are found serially from back to front a back plug, a cylindrical pressure chamber in which is a reciprocable piston having a piston extension projecting forwardly, in one embodiment an intermediate or ejector pin normally abutting the piston extension, and a formed-part die at the forward end of the casing, one wall of which is provided by the distal end of the ejector pin in its retracted position. In a second embodiment, the piston extension serves as an ejector pin. In the first embodiment, retraction of said ejector pin and motor is accomplished by the entry of a new part into the die. In the second embodiment, hydraulic fluid is introduced to drive the piston back for a second cycle. These parts in retracted position in the casing provide a sturdy column to transmit forming pressure through the back plug, the piston and the ejector pin to shape a part held in the formed-part die as two platens of a header or press approach each other. Means is then provided for introducing pressure fluid in a cylindrical pressure chamber causing the piston and the ejector pin to move forward and eject the formed part. In the cylindrical pressure chamber, there are substantially equal pressure-exposed areas in opposite directions, one against the back plug and one against the piston, so that when hydraulic fluid is introduced into the pressure chamber to cause an ejection, the entire device tends to remain stationary.

4 Claims, 6 Drawing Figures U.S. Patent Oct. 14, 1975 Sheet 1 of4 3,911,718

US. Patent Oct. 14, 1975 Sheet 2 of4 3,911,718

FIGZ B FIG?) WJ/W US. Patent Oct. 14, 1975 Sheet 4 Of4 3,911,718

HYDRAULIC EJECI'ION DEVICE BACKGROUND OF THE INVENTION The hydraulic ejector device of this invention is intended for use in bolt makers, cold headers, cold nut formers, I-Ii-pro headers, progressive cold formers, hydraulic presses, punch presses, and injection molding presses and similar types of machinery. The present invention provides a means for up-dating older equipment so that it will be more competitive with newer machinery. It is a small, self-contained unit which can be readily attached or detached from a piece of machinery. Also, it has only a few parts so that it is simple to make and to maintain. A cooling factor increases tool life.

An object of this invention is to provide a unitary, self-contained hydraulic ejector for use in part-forming machinery such as headers and presses.

Another object of the invention is to provide such an ejector device comprising a few parts such as a casing with a through opening in which are assembled a back plug, a piston reciprocable in a pressure chamber with a forward extension, or with an intermediate or ejector pin, the distal end of which forms a wall of a formedpart die at the front end of the ejector device.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

FIG. 1 is a central sectional view through the first embodiment of the hydraulic ejector device of this invention with the ejecting pin in its retracted position;

FIG. 2 is a view similar to FIG. 1 with the ejecting pin in its projected position;

FIG. 3 is a fragmental sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a schematic diagram showing the proposed hydraulic system for operating the ejecting device of the first embodiment;

FIG. 5 is a central sectional view through a second embodiment with the parts retracted; while FIG. 6 is a view similar to FIG. 5 with the parts in ejecting position.

Referring now to FIGS. 1 and 2, a special holder or bolster is shown at 10 which is specially designed to receive the hydraulic ejector device of this invention. It has a planar rear face 11 and a forwardly projecting sleeve 12 and a passageway shown at 13 permitting the introduction of operating pressure fluid to the hydraulic ejector device. A central through opening 14 is provided to receive the hydraulic ejector device of this invention.

The unitary, self-contained hydraulic ejector unit 15 is generally cylindrical and adapted to slide into the opening 14 by entrance from either end. The ejector assembly is independently adjustable about its longitudinal axis with reference to the holder. There is a cen- I tral through opening 16 through the casing 15, in which there are assembled the following parts. Beginning at the rear end, at the right in FIG. 1, a threaded opening 17 receives a back plug 18 which is sealed against the bore 16 by an O-ring seal 19. Next is found a piston 20 which preferably has a rearward extension 20a and a forward extension 20b. An annular pressure seal 21 fits tightly between an annular groove 22 and the bore 16.

The forward piston extension 20b slides snugly in a reduced portion 16a of the central opening 16. As seen in FIG. 1, this abuts against the head 23a of an intermediate or ejector pin 23, the head 23a being a snug sliding fit in the bore 16a. At the front end of the central opening of the casing there is inserted, as by a press fit, or otherwise, a formed-part die 24. This die conforms to the shape intended to be produced and is here shown suitable for forming a head on a bolt or the like. It will be noted in FIG. 1 that the wall 24a of the die is formed by the distal end of the ejector pin 23, which forms a piston rod ejector extension.

The portion of the bore 16 in which the piston 20 travels forms a cylindrical pressure chamber into which pressure fluid may be introduced to move the parts from the position of FIG. 1 to the position of FIG. 2. To this end, a plurality of openings 25 are provided extending through the walls of the casing 15 to receive pressure fluid introduced at 13. Referring to FIG. 3, it is desirable to have a plurality of openings 25 spaced around the casing 15 so as to provide quick access of the pressure fluid over the entire piston 20. Preferably, a pressure distributing chamber 26 is provided by an annular area cut into the special holder 10 radially outside of the casing 15 and opposite the openings 25. An

annular area is cut into the outside diameter of the ejector case. This is required so as not to damage the ejector holder pressure seals.

Referring to FIG. 2, attention is called to the pressure chamber 16 and the substantially equal pressureexposed areas 18a on the back plug 18 and the combined areas 20 and 20a on the piston. Because of this arrangement, when pressure fluid is introduced through 13 and 25, it exerts equal pressures both forward and rearward so that the ejector pin 23 may eject the formed part with practically no tendency to cause any movement endwise of the casing 15.

It will be noted that there are annular resilient pressure seals 27 seated in suitable annular recesses in the holder 10. 7

It will be understood that in the use of this invention, the holder 10 is positioned inthe platen or header slide so that the rear end of the casing 15 is against one of the adjustable wedges 28 of one of the press platens while the work to be formed is manipulated by any standard transfer device to position the part between the die 24 and the other platen (not shown) opposite the platen holding wedge 28.

Suitable mechanism is provided to introduce pressure fluid at 13 through line A and to return the same to a main reservoir R through line B. One such system is shown in FIG. 4. Electric motor M, through flexible coupling FC, drives a fixed displacement pump PF. This pump draws hydraulic oil from the reservoir tank R through a strainer ST and pumps the same into the accumulator ACC to the desired pressure setting which merely as a safety device to insure against malfunction of the pressure switch or unloading valve and thus eliminating the possibility of uncontrolled pressure build-up which would cause serious system damage. The twoway solenoid valve V is illustrated with a solenoid SB energized. In this position, the valve spool has been shifted to the return position. This is the period of the cycle in which the accumulator is charged with the maximum system pressure. A pressure gauge PG is in stalled between the valve V and the accumulator to record the stand-by pressure of the system. The cam and micro-switch which is used to control the valve V is not shown in this diagram.

During the forming operation of the machine cycle, the solenoid valve SB is energized as illustrated in FIG. 4. The cam for operating the solenoid SB and SA is mounted on the end of the reciprocating crank shaft of the header or press and is adjusted to strike the solenoid valve SB preferably at the forward dead center position of such crank shaft. This timing point is determined by the customer to meet his particular partsforming requirements. The timing may be set before dead center unlike mechanical units. When solenoid SA is so energized, the solenoid SB is de-energized allowing the spool within the valve V to be shifted to the pressure position. At this time, the stored pressure fluid within the accumulator is allowed to disperse through the check valve C2 into the ejector E, thereby completing the ejection cycle. As illustrated in FIG. 4, when the piston 20 in the ejector E is depressed mechanically inward, the hydraulic oil is forced through line B on through the check valve C3, after which it continues back through the two-way solenoid valve V and through a heat exchanger HE to cool it and then on through a filter F back to the reservoir R. In fact the hydraulic oil is always directed through the cooler except during the ejecting cycle. The ejector pin 23 remains in the position of FIG. 2 until the next part to be formed is moved to the right in FIG. 2 by its connected platen which then pushes the parts 23 and 20 back to the position of FIG. 1, being stopped by the back plug 18.

During the ejecting cycle, all pressures are contained within the ejector casing 15, thereby eliminating practically all stress induced on the bolster or on workstuds. Practically all mechanical type ejectors presently known to me induce added strain and consequently wear on various machine members and parts. The ejector of this invention may be loaded and pressure applied with literally no physical means of retaining the ejector casing within the holder 10. However, means for securing the ejector casing is provided. The part can be ejected and the ejector device will remain practically stationary.

By designing into this system two check valves C2 and C3 with their opposite free flow directions, the following has been accomplished.

a. The elimination of entrapping air between the valve V and the ejector E. Entrappment of air at this point would cause a cushion effect on the ejector piston, thereby lowering the effectiveness of the ejector because of reduced oil pressure.

b. By expelling the total volume of oil in the ejector case back to the reservoir, a cooling effect of the ejector case is accomplished. This means that cooler hydraulic oil is circulated through the casing at each operation of the cycle, thus cooling the part-forming insert 24. It is not uncommon for dies in cold forming machinery to attain temperatures in the area of 300 to 400 Fahrenheit. With this invention, the hydraulic fluid in the ejector unit is constantly being recirculated back to the reservoir tank R through the oil cooler or heat exchanger HE. The recirculation of this fluid through the ejector unit will tend to carry away some of the heat, thereby reducing the temperature of the forming die which increases die life. This is an impor tant feature of this invention.

Another important feature is that the position of the parts in FIG. 1 utilizing the sturdy construction of piston 20 and pin 23 strongly resists the forming pressure exerted between the platens on the part resting in the die 24.

It should be understood that one or more ejector units may be connected to lines A and B so as to eject a plurality of parts simultaneously or individually.

A second embodiment of this invention is shown in FIGS. 5 and 6 of the drawings. This shows a machine designed to make a socket head cap screw, or other similar object which needs a die male part as shown at 31 to form a female end on the work piece placed in the opening at 24. Here the special holder 10 is like that previously described insofar as the passage 13' is like the passage 13 mentioned in FIGS. 1 and 2. Another opening for the admission of hydraulic pressure fluid is indicated at 32, as will presently appear.

Here the casing 33 has a central through opening into which is threaded a back plug 34 resting against the wedge 28' carried by one of the header or press platens, then a movable piston 35 reciprocatable in the cylinder combustion chamber 36 and having an elongated extension 35a extending forwardly in an annular manner to a level at 35b (when the parts are retracted) where it becomes part of the die holding the piece to be formed in the opening 24'. This die is indicated at 3'7 as being a press fit, or the like, at the left-hand end of FIGS. 5 and 6. The male die part 31 is firmly fixed and supported by the male die extension support pin 38 which is supported by a threaded pin 39 in the back plug 34.

In this embodiment, the passages for introduction of hydraulic fluid through 13 to the compression chamber 36 includes a plurality of passages 25 supplied from an annular oil pocket 26 as described in connection with FIGS. 1 and 2. However, the additional hydraulic fluid introduction opening 32 is provided leading through an annular hydraulic fluid pocket 40 to a plurality of passageways 41 leading into the compres sion chamber 36 to apply pressure on the down stream face of the piston 35 when necessary.

Annular pressure seals are provided at all of the points indicated in the drawings.

The operation of the second embodiment is like that described in the first embodiment in connection with FIG. 4. With the parts assembled as shown in FIG. 5, a piece to be formed is positioned in the opening 24 in the die 37 by means carried by one of the platens of the header or press. The platens at opposite sides of FIGS. 5 and 6 then are caused to approach each other in the usual manner in headers or presses and forming pressure is applied on the piece to be formed which is firmly supported by the casing 33, the die 37, the piston 35 and its extension 35a, the same being backed up against the back plug 34 held by the wedge 28', and by the male die 31, its supporting pin 38 and again the pressure being conducted through the back plug 34. When the part is formed, hydraulic pressure fluid is introduced through 13 and 25 to the right-hand end of compression chamber 36 causing the piston 35 and its extension 35a to move forwardly to the position of FIG. 6, thus stripping and ejecting the formed socket head cap screw, or the like, moving it out of the indented chamber 24. Thereafter, hydraulic fluid is introduced through the opening 32 and passageways 41 by means not shown to the left-hand end of the compression chamber 36, as viewed in FIGS. 5 and 6, against the down stream face of the piston 35, thus moving it back to the starting position of FIG. 5.

The apparatus shown in FIGS. 1, 2, 5 and 6 can be adjusted to take care of changes in the die 24 or 37 as these dies become worn and are reground. The adjustment is limited by the distance between the points A and B indicated on FIGS. 1 and 5.

It will be seen that this invention provides: (a) A doublc acting device which acts as a stripper and ejector; (b) provides dissipation of tooling temperature (at dies 24 and 37) through recirculation of hydraulic fluid through the heat exchanger HE and the reservoir R; (0) variable infinetely in precise timing, by adjustment of the cam for operating the solenoid SB and SA, which cannot be accomplished with present mechanical devices; and (d) longitudinal adjustment of the ejector within the ejector holder as noted in the dimensions A and B.

What is claimed is:

1. A unitary, self-contained hydraulic ejector for use in part-forming machinery such as headers and presses; comprising a generally cylindrical ejector causing adapted to be held snugly in, and longitudinally adjustable in, a complementary opening in a special holder or bolster in a header or the like; there being a central through opening in said casing; hydraulically operable piston-motor means in said central through opening including a piston reciprocatable in a pressure chamber and a piston rod ejector extension responsive to operation of said motor means to eject a formed part, a back plug closing the rear end of said through opening, there being a part-forming die having an opening including pressure-receiving walls in the front end of said casing in line with said ejector extension, there being an hydraulic pressure fluid passage through said casing communicating with said motor means pressure chamber in position to urge said piston-motor means forward in an ejection direction, said parts in said casing through opening including a direct pressure-transmitting train in non-ejecting position from said pressure receiving walls to said back plug, said back plug being positioned to receive pressure directly from a press platen, and said cylindrical pressure chamber having substantially equal pressure-exposed areas in opposite directions, one on said back plug and one on said piston, practically eliminating endwise stress, whereby said casing may be fixed in operating position in a header or press and pressure applied in a known manner between two platens to form a part introduced into said part-forming opening, after which hydraulic pressure fluid may be admitted to said piston-motor means to eject the formed part.

2. An ejector as defined in claim 1, including an hydraulic fluid storage reservoir, circulation means providing fluid flow from said reservoir to said casing and means for return flow of said fluid from said casing through a heat exchanger to said reservoir, whereby heat is conducted from said part-forming die through said casing and through said parts in said central through opening to said hydraulic fluid before it returns to said reservoir.

3. An ejector as defined in claim 1, wherein said ejector extension is an intermediate pin in line with and in engagement with said piston of said piston-motor means when said parts are in ready-to-eject position.

4. An ejector as defined in claim 1, wherein said ejector extension is an extension of said piston; there being a central through opening in said piston and extension; a male die holding pin passes through said last named opening and is secured to said back plug; and means is provided for supply of hydraulic pressure fluid through said casing selectively to opposite faces of said piston.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat n 3.911.718 Dated October I4 1975 Inventor(s) Robert E, Requarth It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 1, line 3, "causing" should read casing".

Signal and Scalcd this I thirtieth Day of December 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Ave-sting Officer Commissioner a] Forum and Trademarks

Claims (4)

1. A unitary, self-contained hydraulic ejector for use in partforming machinery such as headers and presses; comprising a generally cylindrical ejector causing adapted to be held snugly in, and longitudinally adjustable in, a complementary opening in a special holder or bolster in a header or the like; there being a central through opening in said casing; hydraulically operable piston-motor means in said central through opening including a piston reciprocatable in a pressure chamber and a piston rod ejector extension responsive to operation of said motor means to eject a formed part, a back plug closing the rear end of said through opening, there being a part-forming die having an opening including pressure-receiving walls in the front end of said casing in line with said ejector extension, there being an hydraulic pressure fluid passage through said casing communicating with said motor means pressure chamber in position to urge said piston-motor means forward in an ejection direction, said parts in said casing through opening including a direct pressure-transmitting train in non-ejecting position from said pressure receiving walls to said back plug, said back plug being positioned to receive pressure directly from a press platen, and said cylindrical pressure chamber having substantially equal pressure-exposed areas in opposite directions, one on said back plug and one on said piston, practically eliminating endwise stress, whereby said casing may be fixed in operating position in a header or press and pressure applied in a known manner between two platens to form a part introduced into said part-forming opening, after which hydraulic pressure fluid may be admitted to said piston-motor means to eject the formed part.

2. An ejector as defined in claim 1, including an hydraulic fluid storage reservoir, circulation means providing fluid flow from said reservoir to said casing and means for return flow of said fluid from said casing through a heat exchanger to said reservoir, whereby heat is conducted from said part-Forming die through said casing and through said parts in said central through opening to said hydraulic fluid before it returns to said reservoir.

3. An ejector as defined in claim 1, wherein said ejector extension is an intermediate pin in line with and in engagement with said piston of said piston-motor means when said parts are in ready-to-eject position.

4. An ejector as defined in claim 1, wherein said ejector extension is an extension of said piston; there being a central through opening in said piston and extension; a male die holding pin passes through said last named opening and is secured to said back plug; and means is provided for supply of hydraulic pressure fluid through said casing selectively to opposite faces of said piston.

Images