US2290917A

US2290917A - Lens molding press

Info

Publication number: US2290917A
Application number: US363322A
Authority: US
Inventors: Charles V Smith
Original assignee: Univis Lens Co
Current assignee: Univis Lens Co
Priority date: 1940-10-29
Filing date: 1940-10-29
Publication date: 1942-07-28
Anticipated expiration: 1959-07-28

Description

July 28, 1942; c. v.' SMITH LEENS MOLDING PRESS Filed Oct. 29, 1940 INVENTOQ .CHAQLES V SMITH MR/MAI,

by ATTORNEYS Patented July 28, 1942 LENS MOLDING PRESS Charles V. Smith, Dayton, Ohio, assignor to The Univis Lens Company, Dayton, Ohio, a corporation oi Ohio Application October 29, 1940, Serial No. 363,322

15 Claims.

This invention relates to die apparatus used in forming various materials.

It is an object of the invention to provide a simplified die holding apparatus, and one which may be constructed relatively inexpensively.

Another object of the invention is to provide a die holding device having means for the circulation of fluid therethrough, the fluid passage being finned for greater thermal transfer of heat.

Another object of the invention i to provide a die holding apparatus wherein the die element i arranged in good thermal transfer with fluid circulating therethrough, and is removably positioned within the die holding apparatus.

It is another object of the invention to provide a die holding apparatus wherein the die element is removably positioned, and wherein the means for removably supporting the die element providcs means for aiding the thermal transfer of heat between the holding device and the die element.

Another object of the invention is to provide a forming die and holding apparatus wherein fluid is circulated through the die, or holding apparatus, and wherein means are provided for insuring that the fluid passage is completely filled with fluid when circulating therethrough.

Another object of the invention is to provide means for adjusting the position of the perpendicular axis of the die with respect the platen of a forming press.

A still further object of the invention is to provide means for coaxially aligning a pair of die elements, which means.is removable, upon the die elements being positioned properly within a forming press.

A still further object of the invention is to provide a simplified forming press for forming small motor provides the power element for operating the press, the motor being operated either by pneumatic or hydraulic pressure.

Another object of the invention is to provide a simplified formin press for forming small masses of material at relatively low pressures.

Further objects and advantages will be apparent from the description and the drawing.

Inthe drawing:

Figure 1 is a vertical cross-sectional view of a forming press having die holding devices and die elements positioned therein constructed in accordance with the teachings of the invention;

Figure 2 is a horizontal cross-sectional view taken along line 2-201? Figure 1;

Figure 3 is a cross-sectional view of a portion of the die holding'device and die elements, showing the means for aligning the die elements and holding devices.

In this invention a simplified forming press is provided wherein the die holding elements are of a simplified construction, and wherein the forming die elements are removably positioned.

The die elements, and the die holding members are provided with means for coaxially aligning thedie members for insertion into the simplifled press. Upon positioning the die holding members with their die inserts therein within the forming press, in their aligned condition, suitable means is provided for properly supporting the die holding members upon the platen and the head of the press so that the aligned relation of the die holding members, and thus the die elements, is maintained.

The simplified die holding members I0 and Illa consist of an internally threaded cylinder II..

This cylinder II can be a common internally threaded pipe member, the accuracy of the threads I2 being of no particular value. The cylinder H is cut from a length of the internally threaded pipe to the desired length to provide the body for the die holding member In. Since the die holding members l0 and Illa are of identical construction only one of said members will be described, it being understood that like parts are represented by like numerals. A mounting plate I 3 is positioned adjacent one end of the cylinder II, the cylinder being secured to the plate l3 by suitable means such as brazing or welding, as indicated at I. The mounting plate I 3 thus seals one end of the cylinder H.

The opposite end of the cylinder II is closed by means of a disk l5 which is provided with external threads I 6. The threads l6 ar adapted to match the threads I! of the cylinder ll so that the disk l5 can be threaded into the open end of the cylinder II. The disk I5 is positioned a substantial distance inwardly from the end l8 of the cylinder ll whereby a recess is provided in the end of the cylinder ll between thedisk l5 and the end of the cylinder. The disk I5 is secured in position within the cylinder II by suitably fastening the disk therein through such means as brazing or welding. A plurality of circular slots I9 are positioned in the inner face of the disk I5. These slots are for the purpose of providing additional surface area to the inner face of the disk IS. The mounting plate Bend the disk [5 thereby provide a sealed chamber 20 within the cylinder II. The chamber 20 is provided with a fluid inlet 2| and with a fluid outlet 22. The fluid outlet 22 is provided with means for restricting the outlet 22, such as the valve 23. While a valve 23 is used for purposes of restriction in the outlet 22, the valve 23 may be dispensed with if the discharge line 22 is of smaller diameter than the inlet line 2|.

This restriction to the flow of fluid through the chamber 20 is provided. to insure that the chamber 20 is completely fllled with fluid circulating therethrough. Since the inlet 2| can pass more fluid than the outlet 22, when the valve 23 is restricted, it may be seen that the chamber 20 will be completely fllled'with fluid in thermal transfer with the walls thereof. It is, of course, to be understood that the use of the valve 23 is optional, but its use is advantageous to insure complete filling of the chamber 20 and to prevent short-circuiting of fluid from the inlet directly to the outlet opening.

When using cooling and heating fluid for cooling and heating the die carrying members I l and Ila it is, of course, desirable. that the fluid outlet shall be arranged in a manner that the chambers 20 can be drained of fluid. Hence, the fluid outlet is usually positioned at the lowest point of the chamber 20. In the case of the upper die carrying member II), a short-circuiting of fluid between the inlet and the outlet is not as serious as in the case of the lower die carrying member Ila. If the fluid circulating through the chamber 20 short-circuits between the inlet 2| and the outlet 22 of the die carrying member Ila it may readily be seen that the disk of the die carrying member Ila will not have good thermal transfer with the maximum quantity of inlet fluid circulating into the chamber 20. Hence, the restrictions in the outlet 22 are of value to insure that the end closure disks I5 will be in heat exchange relation with the maximum volume of fluid passing through the chamber 20.

As heretofore mentioned, the cylinder II consists of an internally -threaded pipe member, hence the threads I2 will extend throughout the length of the chamber 20. These threads provide means for increasing the surface area of the chamber exposed to the fluid circulatin therethrough, and in effect provide fins for the internal surface of the chamber 20. The circular grooves I 9 provided in the end closure disks I5 increase the surface area of the disk exposed to the fluid within the chamber 20, and hence the portions between the grooves I9 serve as heat transfer fins for the disk I5.

The die element is removably positioned within the recesses provided between the outer exposed face of the disk I5 and the end I 8 of the cylinder II. The die element 30 consists of a disk 3| which is provided with external threads 32 which are adapted to engage the threads I2 within the cylinder II to retain the die 30 in position within the recess. The threading of the disk 3| into the recess provides a means whereby the heat transfer area between the cylinder II and the disk 3| is increased, the threads servin this purpose. Also, the disk 3| is in thermal transfer relation with the end closure disk I5. The disk 3| of the die 30 carries a forming die insert 35. This insert 35 is suitably secured within the carrying disk 3|, and may consist of any one of a number of materials suitable for forming masses of material under pressure. The exposed faces of the inserts 35 are provided with the desired contour which will produce an article of the desired shape when the die members 35 are brought into the proper adjacent relation. It is of course to be understood that the die inserts are not essential but that the contoured face could be provided upon the disk 3|.

In order to strengthen the end closure disks I5 for the cylinder II a centrally disposed post 33 is positioned between the disk I5 and the mounting plate I3. The post 36 is suitably attached to the disk I5 and the mounting plate I3.

The die carrying members I3 and Ila are suitably positioned within a forming press, which in this invention consists of a stationary head 4la which forms apart of the press frame 40 and a movable platen H. The movable platen H is mounted upon the end of a plunger 42 whichis connected to a diaphragm type motor 43. The motor 43 is mounted upon the bed portion of the frame 40 of the press. The bed and the head 40a are both parts of the press frame 40 and are stationary with respect each other. The plunger 42 is guided in its reciprocal movement by means of a plurality of rollers 44 mounted therearound. The rollers 44 are bearinged upon the press frame 40 in any suitable manner, as by the axles 45. The diaphragm motor 43 provides an extremely simplified form of press motor, and improves the performance of the forming operation in that the platform 4| can be moved in an absolutely uniform stroke. Since the diaphragm motor 43 is a friction-free piece of apparatus, and since the rollers 44 are also friction-free apparatus with respect to the movement of the plunger 42, it can be seen that slight additional pressure application to the motor 43 .will produce a corresponding movement of the platen 4|.

When molding or forming certain articles,

such as optical articles, and more particularly lenses, it is essential that the movement of the die member shall be at an absolutely uniform rate. The use of a diaphragm motor permits the movement of the die at a uniform rate and eliminates all vibration or jerky movement of the platen 4|. The diaphragm type motor 43 is particularly advantageous for use in forming optical articles since this type motor is a friction-dfree piece of apparatus. When using a conventional forming press there is a slight amount of vibration produced in the plunger caused by the pressure against the .plunger overcoming the friction of the sealing device for the plunger. Such vibration is not produced when using a diaphragm type motor. Further, these motors can be used with either pneumatic or hydraulic presses and since the pressures involved when forming optical articles from resinous material are not high, it is quite possible to use ordinary city water pressure as the press operating means, or air pressure of like degree.

The die carrying members I0 and Ila are secured to the platen 4| and the head 40a of the press frame 40 by means of mounting bolts Il which extend through the mounting plate I3 into engagement with the platen 4| and the head 40a of the press frame.

To provide for proper alignment for the die carrying members I. and Ila, and thus for the die elements 35, a circular groove ll is provided in the die supporting disks 3|. These grooves II are concentric with the central axis of the die inserts 35, and thus concentric with the axis of the contoured surface of-the die insert 35. A hollow cylinder BI is adapted to be positioned within the grooves 60 in order to provide proper alignment of the die inserts 35. The hollow cylinder 6| will thus cause the grooves I! to be brought into proper coaxial alignment, and since the grooves 60 are concentric with the axis of the contoured face of the disk 38 it may be seen that the inserts 35 will be brought into coaxial alignment.

It is of course to be understood that the die elements 30 have been previously positioned within the respective die carrying members III and Illa, so that when the die elements 30 have been properly aligned, the die carrying members It and lfla will also be in proper coaxial alignment. The die carrying members I. and Ilia are then positioned between the platen H and the head 40a of the press frame of the forming press in this assembled and aligned relation. To maintain this aligned relation a plurality of adjusting screws 65 are in threaded engagement with the mounting plate I3. These screws 65 engage the surfaces of the platen ll and the head 40a adjacent the mounting plate It. By .properly adjusting the screws 65 so that the ends thereof engage the platen 4| and the head 40a it may be seen that the mounting support for the die carrying members III and lid can be adjusted in a manner that slight angular irregularities between the die carrying members and the platen and head of the press can be compensated for, to permit the maintenance of the proper coaxial alignment of the die elements 30. After the adjustable supporting screws 65 have been properly adjusted the binding bolts 50 may then be drawn tightly against the mounting plates I! to secure the die carrying elements It and Ifla 'at their proper aligned relation. The

platen and head of the press can then be opened to permit removal of the ring 6| from between the die carrying disks 3|. V

By the use of the ring ii and the adjusting bolts 65, it may be seen that I provide means for coaxially aligning the die elements 30 and the die members l and Illa, and also provide means whereby the angularity of the axis of the die carrying members perpendicular to the platen and head of the press can be altered slightly to correct misalignment. It is also possible to use the adjusting bolts 65 as means for obtaining angular relation between the perpendicular axis of the die carrying members I and Illa, should such angular misalignment be de-.

sired.

The structure of the die carrying members, the adjustments therefore, and the structure of the press, as described in this invention, are particularly adaptable for use in connection with the a forming of optical articles from resinous mateials. When forming a mass of resinous material it is not required that tremendous pressures be used, hence the construction of the die carrying members and the dies, can be greatly simplified to the extent wherein lighter structure can be the mold are not at exactly the same temperature as other portions. Since optical work requires exacting production, it may beseen that used than has heretofore been common when molding or forming masses of material. Further, I have been able to simplify the die structures, and die carrying members to such an extent that the production cost of the dies and press are considerably reduced, whereby the advantages of single mold cavities for the production of optical articles can be used advantageously. When producing articles of resinous material it is required that all articles be heated or cooled uniformly. Such uniform cooling or heating is not possible in a multiple mold since fluid passingthrough the mold will lose some of its heat transfer value, whereby certain portions of such inaccuracies as would result from slightly different expansion of different parts of the mold would be detrimental. Further, since the production of optical articles requires that the mold surfaces be in constant engagement with the articles during forming and also while the articles are being set, it may be seen that any non-uniformity of spacing of the mold elements would cause some of the mold surfaces to permit the formed mass of material to draw away from the mold surfaces. Hence, the follow up of the mold surface, required by shrinkage of the material, would not be uniform, and would result in nonuniformity of the articles produced in the multiple mold. Hence, by simplifying the mold structure, the advantages of single mold structures, such as uniformity of heating and cooling, uniformity of follow up, and uniformity of surface alignment, are brought within the economical range for production use. I

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A forming apparatus comprising a die carrying member, means for securing a die to said member, means for supporting said die carrying member, flange means extending from one end of said member, means extending through said flange means for angularly adjusting the axis of said member with respect to the supporting means, and means extending through said flange means into engagement with said supporting means for securing said member to said supporting means.

2. A forming apparatus comprising a die carrying member, means for securing a die to said member, means for supporting said die carrying member, flange means extending radially from one end of said member, means extending through said flange means in threaded engagement therewith for angularly adjusting the axis of said ,member perpendicularly with respect to the supporting means, and means extending through said flange means into threaded engagement with said support for retaining said membertin adjusted angular position upon said suppor 3. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate abutting one end of said body and sealed thereto, and a second closure plate threaded into engagement with the threads in the opposite end of said bore and sealed thereto, the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wall to receive and support a die member.

4. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate secured to said body for sealing one end of said bore, and a second closure plate threaded into engagement with the threads in the opposite end of said boreand sealed thereto to provide a closed chamber, the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wallv to receive and support a die member, said chamber having a fluid inlet and a fluid outlet for the circulation of fluid therethrough. Y

5. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate secured to said body for sealing one end of said bore, a second closure plate threaded into engagement with the threads in the opposite end of said bore and sealed thereto to provide a closed chamber, .the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wall to receive and .support a die member, said chamber having a fluid inlet and a fluid outlet for the circulation of fluid therethrough, and means for restricting the flow of fluid from said chamber to insure complete filling of said chamber with fluid in thermal exchange therewith.

6. A forming apparatus comprising an internally threaded cylinder, a mounting plate abutted against one end of said cylinder and sealed thereto, an externally threaded. disk threaded into the opposite end of said cylinder a substantial distance to provide a recess in the end of said cylinder and sealed in said position, a plurality of annular recesses in the inner face of .said disc, a fluid inlet and a fluid outlet for said cylinder and a die member removably positioned in said recess.

7. A forming apparatus comprising an inter nally threaded cylinder, a closure plate secured to one end of said cylinder for sealing said end, an externally threaded disk threaded into the opposite end of said cylinder a substantial distance to provide a recess in the end of said cylinder and secured in said position, said disk sealing said end of said cylinder whereby an internal chammr is provided, fluid inlet and outlet means for said chamber, and a die member removably positioned in said recess in threaded engagement with said cylinder threads and in thermal contact with said disc.

8. A forming apparatus comprising an internally threaded cylinder, a mounting plate secured to one end of said cylinder for sealing said end, an externally threaded disk threaded into the opposite end of said cylinder a substantial distance to provide a recess in the end of said cylinder and secured in said position, said disk sealing said end of said cylinder whereby an internal chamber is provided, fluid inlet and outlet means for said chamber, and a, die member removably positioned in said recess in threaded engagement with said cylinder threads and in thermal contact with said disk whereby said die is heated or cooled by fluid circulating through said chamber.

9. An apparatus for forming a mass of material comprising, a pair of forming die elements, means for supporting said die elements in operative relation, means for securing said die elements upon said supporting means, and means for coaxially aligning said dies when positioning the same upon the supporting means, comprising an annular recess in each of the adjacent faces of the die elements concentric with the axis of said elements, and a loose hollow cylinder removably positioned in the adjacent cooperating recesses to coaxially align the same.

10. A forming die comprising, an internally threaded cylinder, a mounting plate secured to on end of said cylinder forming a closure therefore, an externally threaded disk in threaded engagement with said cylinder threads and positioned a substantial distance inward from the end of the cylinder to provide a recess, means for securing said disk in said position, a fluid inlet and outlet for the chamber provided by the cooperation of the cylinder and end closure devices, and a forming die removably positioned within said recess by engagement with said cylinder threads.

11. A forming die comprising, an internally threaded cylinder, a mounting plate secured to one end of said cylinder forming a closure therefore, an externally threaded disk in threaded engagement with said cylinder threads and positioned a substantial distance inward from the end of the cylinder to provide a recess, means for securing said disk in said position, a fluid inlet and outlet for the chamber provided by the cooperation of the cylinder and end closure devices, a forming die'removably positioned within said recess by engagement with said cylinder threads, and means for adjusting the angularrelation of the axis'of the di with respect to the supporting means therefore.

12. The method of aligning a pair of die elements within a forming press comprising, the step (a) of positioning an aligning device upon one of the forming dies in coaxial alignment with the axis thereof, the step (b) of coaxially positioning the cooperating forming die upon said aligning device, the step (c) of positioning said aligned assembly within a forming press, the step d)- of adjusting the die supporting means to the angularity of the press pressure plates to maintain the coaxial die alignment, and the step (e) of securely fastening the dies to the press pressure plates in said coaxially aligned position.

13. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate abutting one end of said body and sealed thereto, a second closure plate threaded into engagement with the threads in the opposite end of said bore and sealed thereto, the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wall to receive and support a die member, and a support member extending between said closure plates.

14. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate abutting one end of said body and sealed thereto, a-second closure plate threaded into engagement with the threads in the opposite end of said bore and sealed thereto, the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wall to receive and support a die member, and a support member extending between said closure plates and secured to each of said plates.

15. A carrying member for a forming die comprising, a body having an open ended threaded bore, a closure plate abutting on end of said body and sealed thereto, a second closure plate threaded into engagement with the threads in the opposite end of said bore andsealed thereto, the outer face of said last mentioned plate being positioned inward of the end of the bore to provide a recess having a threaded wall to receive and support a die member, and a support member extending between said closure plates and positioned coaxially with said bore.

CHARLES V. SMITH