Background of Invention
This invention relates to the improvements in quench presses used for the precision quenching of gears, bearing rings, and other flat and/or cylindrical shaped parts. Generally, the quench press is used to help correct the distortions that exist in a part immediately prior to the press quenching operation. Additional distortions that are caused by the actual quenching process itself are also minimized.
Obtaining a minimum amount of distortion is very critical in the production of gears, bearing rings and other articles. In practice, an allowance of extra material on the part is made in the before-heat treat condition to help insure that the part can be finished after heat treatment to the proper sizes and requirements for roundness, taper, and flatness. If too little allowance is made, or if the part distorts more than predicted, then the part is many times scrapped. If an excessive allowance is made, then the time and/or cost for grinding, lapping, or sizing by other methods increases and thus becomes an even more expensive operation. Press quenching helps the manufacturer minimize the amount of extra material on the part(s) prior to heat treating to minimize the cost of subsequent material removal operation needed to obtain the desired final dimensions. For carburized parts, it is very critical to minimize the distortion existing in a part after heat treatment, so that the material removed from the part in the subsequent sizing operations will leave a uniform effective case-depth on the part. The ability to minimize any distortions existing in the part after heat treatment by using a quench press can reduce the total time required for carburizing because the parts will not have to be carburized to a deeper depth to help insure that the part will have a sufficient case depth where required after the part's final sizing operations are completed. If no material is removed from the part after heat treating, a quench press can help the manufacturer produce a part with less distortions, and therefore, more dimensionally correct.
In most prior art quench presses, the frame of the machine requires heavy and expensive castings or weldments which subsequently require very accurate machining. Additionally, the nonsymmetrical configurations allow misalignment, as the frame deflects from forces involved with the quenching operation. Also in the prior art quench presses, specially designed and manufactured power cylinders would have to be used to obtain unique forces to drive three totally independent concentric rams. These cylinders would be such that they are concentric to each other and pose many problems with sealing and mounting and would be expensive to repair or replace. Also, in the prior art quench presses capable of handling parts larger than 24 inches in diameter, either the lower die plate or the upper die plate and/or rams are made to swing away and thus have a tendency of misalignment. Also in the prior art quench presses it is necessary to change and/or adjust the splash guards or guard for various heights or workpieces at much expense of time and labor, plus the inconvenience of storing and stocking a multiple of splash guards and related fasteners. Also in the prior art quench presses, the bore diameter adjustment is difficult or omitted entirely. One such bore diameter adjusting device uses a threaded spacer nut that is not accessible, is not accurate, but is easily damaged to the point that adjustments are very difficult. Also in the prior art quench presses, access to remove the part from the press has been limited since there is generally only one door or access provided. Also in the prior art quench presses, the proper quenching cycle is not available because no means of delaying the introduction of the quenching media to the quenching chamber were included.
Summary of the Invention
The present invention offers a novel means for overcoming one or more of the problems as set forth above.
According to the present invention, the preferred embodiment of the quench press utilizes a novel arrangement of a plurality of posts or tie-rods with a plurality of horizontal plates such that the posts or tie-rods are equally spaced around the centerline of the quench press so that they absorb the forces, deflections, and thermal expansions of the quenching operation in an equal manner. Such forces, deflections, and expansions do not cause misalignment of the rams to the lower die plate.
Also according to the present invention, the preferred embodiment of the quench press has an arrangement of three concentric rams, each ram being independent and individually controlled as to the force applied, the speed at which the rams move, the number of times that the force or forces are applied, and the amount of time that the force or forces are applied. Each of the rams, other than the center ram, is powered by a plurality of hydraulic or pneumatic cylinders or other force exerting devices that are spaced in such a manner that the forces are evenly distributed. This novel application in the preferred embodiment of inexpensive and relatively common hydraulic or pneumatic cylinders and/or other force exerting devices offers easy repair and replacement and does not tend to cause misalignment of the rams to the lower die plate.
Also according to the present invention, the preferred embodiment of the quench press provides a means of having more than one door or access area to the die or tooling area for installation and/or removal of the tooling and/or operation of the quench press. The preferred embodiment of the quench press will utilize three such doors but the scope of the invention is not limited to three doors or access areas.
Also according to the present invention, the preferred embodiment of the quench press provides for an automatic splash guard that requires neither changes nor adjustments for set-up of various heights of workpieces. Said guard is generally held closed during the quenching process by a plurality of hydraulic or pneumatic cylinders or other force exerting devices such that the position of the splash guard is caused to be adjusted by the movement of the outer die holder or ram.
In the preferred embodiment, said ram is the third or outer ram.
Also according to the present invention, the preferred embodiment of the quench press incorporates a fixed or stationary lower tooling or die plate to insure positive alignment of the rams to the lower tooling or die plate. This accurate alignment is helpful in producing workpieces that are more dimensionally correct.
Also according to the present invention, the preferred embodiment of the quench press incorporates a novel means of adjusting the diameter of the workpiece by adding or removing graduated and properly sized shims or other devices to the positive stop for the center ram such that the bore diameter of the workpiece is decreased or increased as required. The preferred embodiment is to add or remove the shims or other devices from the immediate vicinity of the lower die plate and not from the center ram or its means of transmitting force. Also according to the present invention, the preferred embodiment of the quench press has a novel means of delaying the introduction of the quenching media to the quenching chamber.
As can be seen by the above description, the present invention provides a substantial improvement in the quench press design and operation. These improvements offer reduced manufacturing and maintenance costs by allowing the use of less expensive components and members while still improving and maintaining more accurate alignment. More access to the tooling area and the various components allows easier and faster tooling changes.
In addition, provisions are made to enclose the quench press, to control the flow of quench oil or other quenching media to the workpiece, and to control the force or movements of the various rams.
Brief Description of the Drawing Figures
FIG. 1 is a perspective cut-away view showing the quench press in accordance with the present invention in the preferred embodiment.
FIG. 2 is a front sectional view showing the die or tooling area in an open or load/unload position of the quench press in accordance with the present invention in the preferred embodiment.
FIG. 3 is a front sectional view showing the die or tooling area in the closed or quenching position of the quench press in accordance with the present invention in the preferred embodiment. Quench oil or other quenching media flow is indicated by the heavy arrows.
FIG. 4 is a front sectional view showing the quench press in accordance with the present invention in the preferred embodiment.
FIG. 5 is a top view showing the quench press in accordance with the present invention in the preferred embodiment.
FIG. 6 is a partial top view showing the splash guard and doors of the quench press in accordance with the present invention in the preferred embodiment.
FIG. 7 is a perspective view showing one of the doors of the quench press in accordance with the present invention in the preferred embodiment.
FIG. 8 is a perspective view showing the splash guard of the quench press in accordance with the present invention in the preferred embodiment.
FIG. 9 is a perspective view of the quench press in accordance with the present invention in the preferred embodiment.
Detailed Description of the Quench Press in Accordance With the Present Invention in the Preferred Embodiment
Averting first to FIG. 1, there is illustrated therein a quench press 10 in accordance with the present invention. The press 10 has three vertical posts 11 which absorb the thrust forces of the quenching processes. The three posts 11 are attached to the stationary lower plate 12 that acts as a base for the quench press 10 and also provides a member to which the walls 13 are attached. Another stationary plate 14 is mounted to the upper end of the three vertical posts 11. The plate 14 also serves as a mounting position for cylinder 15, three of cylinders 17, three of cylinders 16, three of cylinders 18, and three of cylinders 19. The arrangement of said cylinders in the preferred embodiment is more readily apparent by reference to FIGS. 5 and 6.
The center ram 20 is attached to one of the cylinders, namely cylinder 15, and expands a conventional segmented quenching die under the impetus of cylinder 15. Three cylinders 16, equally spaced around the centerline of the quench press 10 in such a manner as to share the quenching thrust forces uniformly and equally, are attached to a moveable plate 21. The moveable plate 21 is accurately guided by the three vertical posts 11 by means of precision bushings 22 wherein said bushings 22 are rigidly fixed to the moveable plate 21 and wherein said bushings 22 are free to reciprocate vertically along the three vertical posts 11. The moveable plate 21 is further attached to and rigidly mounted to a ram 23 wherein provisions are made to attach a conventional die or adapter plate. Also, three additional cylinders 17, equally spaced around the centerline of the quench press 10 in such a manner as to share the quenching thrust forces uniformly and equally, are attached to a moveable plate 24. The moveable plate 24 is accurately guided by the three vertical posts 11 by means of precision bushings 25 wherein said bushings 25 are rigidly fixed to the moveable plate 24 and wherein said bushings 25 are free to reciprocate vertically along the three posts 11. The moveable plate 24 is also referred to as a ram and herein said plate 24 has provisions for attaching a conventional die or adapter plate.
The quench oil splash guard 26 is held in contact with the outer ram, previously referred to as a moveable plate 24, by means of three cylinders 19, equally spaced around the centerline of the quench press 10 in such a manner as to share the thrust forces uniformly and equally. Three precision bushings 27 accurately guide the lifting arms 28 which are rigidly fixed to the splash guard 26 and to the three cylinders 19.
A stationary plate serves as the lower die plate 29 and is attached to the base 12 of the quench press 10 by means of the three short vertical posts 30 wherein all are rigidly secured. The three short vertical posts 30 are equally spaced around the centerline of the quench press 10 in such a manner as to share the loads uniformly and equally. The lower die plate 29 has provisions for mounting conventional dies and also has passages provided for flow of the quenching media.
The quench press 10 in the preferred embodiment has a positive stop 31 that also serves as a guide to insure positive alignment of the center ram 20 while in the closed or quenching position. A female conical surface of the positive stop 31 engages a corresponding male conical surface of the center ram 20. Graduated and properly sized shims 32 are added or removed from the positive stop 31 as required to decrease or increase, respectively, the bore diameter of the article being quenched. The operation of the shims 32 can better be visualized by reference to FIG. 3. A change in the vertical position of the center ram 20, because of the matching conical surface of the quenching die, will cause a change in the bore diameter of the article being quenched in a manner in proportion to the tangent function of the conical angle of the center ram 20.
The quench press 10 in the preferred embodiment has a removeable top 34 and cap 33 for access to all of the cylinders for the purpose of replacement or service or components enclosed in by the top 34 or cap 33.
The quench press 10 in the preferred embodiment has provisions for three doors 35 for loading and/or unloading, and set-up, and are actuated by three cylinders 18 and said doors 35 being free to move in a vertical direction. Provisions are made to control any of three doors 35 independently.
The quench press 10 in the preferred embodiment has provisions for the delay of the introduction of the quenching media to the quenching chamber.
Detailed Description of the Operation of the Quench Press
The structure of the quench press 10 of the present invention in the preferred embodiment can better be understood by consideration of the operation of the quench press 10. With the quench press empty, all of the rams raised, the splash guard 26 lowered, and one of the access doors 35 opened, the quench press 10 is ready for a quenching cycle, provided, however, that proper dies have been set-up in the quench press 10 and tested for the correct adjustments.
A hot workpiece is placed into the quench press 10 and the automatic cycle is initiated. First the door or doors 35 will close and the splash guard 26 will move into position such as to form a quenching chamber by contacting the upper die plate or ram 24. Then the center ram 20, ram 23, and moveable plate 24 will move downward into position. Ram 20 will first contact the positive stop 31 and thus expand the conventional segmented die to the proper bore diameter generally conforming to the workpiece after heat treat size. The cylinder 15 exerts sufficient force to restrict the movement of the segmented dies when the workpiece is quenched and tries to contract because of thermal contractions.
Next, the second ram 23 and the third ram 24, moving downward into position, will cause the quenching dies to contact the hot workpiece, thereby causing the workpiece to be held flat or to whatever contour the dies and/or tooling are designed to produce. At this time the quenching oil or other quenching media is caused to fill the quenching chamber and continues to flow thru the passages to extract the heat from the workpiece at a controlled rate or rates until the part is sufficiently cooled. During the quenching, the upper rams, namely the second ram 23, and the third ram 24, are momentarily released several times to allow the workpiece to contract and shrink inwardly without restriction.
After the workpiece has cooled sufficiently, the flow of the quenching media is stopped, the center ram 20, the second ram 23, and the third ram 24 are raised to an "up" position. Then the quenching media is drained and the splash guard 26 is lowered and one of the access doors 35 is opened for removal of the workpiece. Such workpiece is removed and the quench press 10 is ready for another quenching cycle.
After inspection of the first piece, the shims 32 can be added to or remove from the positive stop 31 as required to decrease or increase, respectively, the bore diameter of the next workpiece and any successive workpiece. Provisions are also made for adjusting individually the pressure of each of the rams, the time of each element of the quenching cycle, the number of times the force is momentarily released, and the flow rate of the quenching media during each stage of the quenching cycle.
It will be understood that the above described embodiment is merely exemplary and that those skilled in the art may make many variations and modifications without departing from the spirit and scope of the present invention. All such modifications and variations are intended to be within the scope of the invention as defined in the appended claims.