US 3623211 A
In order to frame a foil portion with a mirror surface, a foil is perforated along a circular line, a marginal zone of the foil is frictionally held within the endless line, the foil is cut along the endless line, and the marginal zone is firmly clamped and moved over a first frame part and tensioned, whereupon a second frame part is pressed against the first frame part and clamps the tensioned foil to the first frame part without any wrinkles or folds.
Claims available in
Description (OCR text may contain errors)
Nov. 30, 1971 G. zUHLKE METHOD OF FRAMING A FOIL PORTION 3 Shntshnt l` Filed Oct. 6, 1969 Fig. 1
i Nov. 3o, 1971 G, ZUHLKE 3,623,211
METHOD OF FRAMING A FOIL PORTION Filed OCT.. 6. 1969 3 Sh0ltl-$hlt I INVENIQR. Gen/wm) 20Hbkc Nov. 30, 1971 G, ZUHLKE 3,623,211
METHOD OF FRAMING A FOIL PORTION Filed Oct. 6. 1969 3 Shuti-Shnt l Fig. 5
5- Faun 9 IU HN!" United States Patent O METHOD OF FRAMING A FOIL PORTION Gerhard Zuhlke, Geroldswil, Switzerland, assignor to Schweiger & Schweizer AG, Zug, Switzerland Filed Oct. 6, 1969, Ser. No. 864,048 Claims priority, application Switzerland, Oct. 21, 1968, 15,674/ 68 Int. Cl. B23p 11/02 U.S. Cl. 29-448 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION It is known to frame mirror-reflecting foils onto large frames, and such mirrors are used for decorative purposes in store window displays. It is difficult to obtain a uniformly tensioned foil part surrounded by the frame, without folds or wrinkles adjacent the frame. When smaller frames are to be provided with a mirror-refiecting foil, for the purpose of making mirrors of average size which can be used as pocket mirrors and the like, folds and wrinkles in the region of the smaller frames cannot be avoided by the prior art. Consequently, foil mirrors have only been used in Very large sizes.
SUMMARY OF THE INVENTION It is one object of the invention to provide a method and apparatus by which glassless foil mirrors of average size can be manufactured in large series.
Another object of the yinvention is to provide a method and apparatus for framing a foil without folds or wrinkles.
Another object of the invention is to produce inexpensive framed mirrors without the use of glass.
In accordance with the invention, a mirror-refiecting foil which is much larger than the area of the mirror to be produced, is tensioned in a plane, and perforated along an endless annular line, whereupon a marginal zone within the line of perforation is frictionally held between a pair of clamping parts. The foil is then cut between the perforated holes, whereupon it is more firmly clamped by pressing the central foil part into engagement with a first frame part. Thereupon, a second frame part is pressed against the first frame part, clamping the foil between the two frame parts, while the marginal zone is pulled out of the clamping means.
` A method, according to the invention, comprises the steps of tensioning a foil in a plane; making perforations in the foil along an endless line surrounding a foil part; frictionally holding an annular marginal zone of the foil part within the endless line; cutting the foil along the endless line; supporting first and second frame parts on opposite sides of the foil part inward of the frictionally ice held marginal Zone; moving the marginal zone beyond the first frame part so that a central foil portion of the foil part surrounded by the first frame part is tensioned; and moving the first frame part, and a second frame part matching the first frame part first into engagement with an annular framing Zone of the foil between the marginal zone and the central foil portion, and then into clamping engagement with the lfirst frame portion while pulling the marginal zone out of frictional engagement whereby the central foil portion is framed.
LIt is preferred to frictionally hold the marginal zone during the cutting of the foil, and to firmly clamp the marginal zone during the tensioning of the central foil portion.
An apparatus according to the invention comprises tensioning means for tensioning a foil in a plane, and being preferably part of transporting means for stepwise transporting a foil web; cutting means having an annular edge formed with circumferentially spaced cutting points, and including cutting edge portions between the cutting points; annular clamping means for frictionally holding or clamping an annular marginal zone of the foil inward of the annular cutting edge; first and second support means for supporting the first and second frame parts on opposite sides of the tensioned foil inward of the annular clamping means; and operating means for operating the cutting means, the clamping means and the `support means in a timed sequence.
Preferably, the operating means first move thev cutting means to a perforating position in which the points penetrate the foil, then move the clamping means to an operative position frictionally holding the annular marginal zone of the foil, then moves the cutting means to a cutting position in which the cutting edge portions cut out a foil part frictionally held by the clamping means, and then move the support means to a framing position in which the first and second frame parts clamp the cutout foil part while the marginal zone is pulled out of the clamping means.
In the preferred embodiment, the cutting means includes an annular wall having an annular cutting edge in which the cutting points alternate with recesed cutting edge portions so that, when the cutting means is moved toward the foil, first the cutting points penetrate the foil and make holes through the same along the endless line, whereupon further movement of the cutting means effects complete cutting of the foil along the endless line.
In the preferred embodiment of the invention, the clamping means include first and second clamping parts. First spring means bias the yfirst clamping part and second spring means bias the second clamping part, the first spring means being weaker than the second spring means so that the first clamping part compresses the Ifirst spring means and engages the second clamping part for frictionally holding the marginal zone, whereupon movement of the first clamping part with the second clamping part compresses the second stronger spring so that the marginal zone is firmly clamped and the foil part is tensioned in the framing position.
The foil preferably consists of polyester, and has a thickness between 5 micron and 20 micron. A mirror-refleeting layer of aluminum is vaporized onto one side of the foil. However, the invention is not limited to the framing of mirror-refiecting foils, and foils framed in accordance with the invention may be used for other purposes.
The novel features which are considered as characteristi'c for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. l is a fragmentary schematic elevation, partially sectioned, illustrating an embodiment of the invention;
FIG. 2 is a fragmentary sectional view illustrating a detail of FIG. 1 on a larger scale;
FIG. 3 is a fragmentary elevation illustrating a portion of a cutting means viewed in the direction of the arrow III in FIG. 2;
FIG. 4 is a fragmentary sectional view corresponding to FIG. 2, but illustrating another operational position; and
FIG. 5 is a fragmentary sectional view illustrating a modified embodiment of a frame provided with a foil in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A foil supply reel 2 is rotatably mounted on a supporting frame 1 and is driven from a motor 3 by a V-belt 4 in the direction of the arrow B. A thin foil having a reecting mirror surface is Wound up on supply reel 2, and is guided over a tensioning roller 6, under a guidey roller `8, and between a pair of transporting rollers 9* and 10, so that the section of the foil web 40 located between rollers 9, and 8, is lo'cated in a plane, and tensioned by tensioning roller 6 which is mounted on a lever arm 5 pivotally supported at its upper end on the supporting frame 1, and being biassed by a spring 7 to urge tensioning roller `6 towards the right as viewed in FIG. l.
Transporting roller 10 abuts transporting roller 9 under pressure, and is turned by means of a lever 11 by a drive motor 12 in the direction 0f the arrow C so that upon each stroke of motor 12, foil web 40 is pulled off the supply reel 2. The tensioned section of foil web 40 is located between a stationary support 19 carrying at its top end a iirst frame part 20, and a movable support 28 carrying at its lower end a second frame part 29 which has a flange with an inner cylindrical face 29a matching the outer cylindrical face 2011 of a flange of frame part 20, as best seen in FIG. 4. In accordance with the apparatus and method of the invention, a substantially circular foil part is framed between frame parts 2t)` and 29 in the tensioned condition obtained by tensioning roller 6. It will be noted that the tensioned section of the foil web 40 is substantially larger than the part thereof which can be framed by frame parts 20 and 29.
The drive motor 12 serves only the purpose of stepwise transporting foil web 40. During the forward movement of foil web 40, tensioning roller 6 is turned against the action of spring 7 to the position illustrated in broken lines in FIG. 1, in which a switch, not shown, is actuated by tensioning means 5, 6 to start motor 3 by which the foil web 40` is unwound from supply reel 2 until tensioning roller 6 assumes a position on the r-ight illustrated in the full lines in FIG. l. In this end position, the tensioning means 5, 6 actuate another switch by which the circuit of motor 3 is interrupted.
Foil web 40 preferably consists of polyester, and has a thickness between 5 micron and 20 micron. The mirror coating on one side of the foil is preferably vaporized aluminum.
`Supporting frame 1 has a base portion with a tubular wall having an inner cylindrical surface 13 provided with a circular groove 14 having rectangular cross-section. A
` tubular clamping part 15 is located within the cylindrical surface 13, and has a Circular outer flange 16 projecting into the annular groove 14. The annular cup face of groove 14 serves as a stop abutment for flange 16 which is urged by springs 17 resting on the lower annular face of groove 14 to move upward to the illustrated end position of the tubular clamping part 15 in which the circular clamping face 118 is located slightly below the tensioned foil section. The annular clamping face 18 is located in a horizontal plane parallel to the plane of the tensioned foil section, and perpendicular to the vertical axis of the apparatus.
The base portion of supporting frame 2 carries a pair of upright guide posts 21 on which a yoke 22 is mounted for up-and-down movement. Yoke22 is fixedly connected with support 28 which carries the upper frame part 29, and is reciprocated by a link 23 pivotally connected thereto and also to a rotary member 25 carrying a pivot 24 on which the upper end of link 23 is mounted. Member 25 is driven by a pulley and drive belt 27 from a motor 26 so that during operation of the motor 26, yoke 22 is reciprocated in up-and-down strokes.
The vertical posts 211 also support cutting means for vertical movement. The cutting means include an annular holder 30 guided by posts 2-1 and located between upper springs 36 abutting yoke 22, and lower spring 37 abutting the top face of the base portion of support frame 1. A oircular knife or cutter 31 is secured to cutter holder 30, movable with the same. Cutter holder 30 has an inner face l32 formed with an annular groove 33l having a rectangular cross-section. A circular clamping part 34 has an outer flange 340 located in groove 33 and abutting the lower annular face of the same due to the action of coil springs 34 which abut the upper face of groove 33. The circular clamping face of the upper clamping part 34 is located in a plane parallel to the plane of the tensioned foil, and opposite the clamping face 18 of clamping part 15. The diameter of clamping part 34 is greater than the diameter `of support 28 and frame part 29, and smaller than the diameter of the circular cutting knife 31. The upper and lower faces of grooves 33 limit the up-and-down movement of Iclamping part 34.
The resilient spring force of springs 17 is greater than the force of springs 35, and the spring force of springs 36 is greater than the spring force of springs 37.
FIGS. 2 to 4 Iillustrate the active parts of the apparatus on a larger scale. As best seen in FIGS. 2 and 3, a cutting means 31 has a circular wall 31a with a lower circular cutting edge 31h which is formed with circumferentially spaced cutting points 38 whose lateral cutting portions define the angle 2a. Intermediate the cutting points 38, cutting recesses 39 are provided bounded by cutting edge portions defining the angle 2,6, which is preferably equal to the angle 2a. Intermediate cutting recesses 39 and cutting point 38 less-slanted cutting portions are located.
When the cutting means 30, 31 is moved downward, the cutting points 38 penetrate the tensioned foil section and form holes in the same along an endless circular line. When cutting means 30, 31 is further moved down rst, the cutting angle a is effective so that slits are formed in the foil without circumferentially stretching the foil. In the same manner, the foil is cut at the ends of the downward cutting stroke of the cutting means 30, 31 by the cutting edge portions forming the recesses 39, the cutting angle /8 being preferably equal to the cutting angle a and effecting cutting through the last rear end portions of the foil between the perforations formed by the points 38. The intermediate less-slanted cutting edge portion effects the cutting between the effective periods of points 38 and recesses 39, and it is sufficient to have a small cutting angle only at the beginning and at the end of the cutting stroke by which the tensioned foil section is first perforated and then cut along a circular line for cutting out a circular central foil part.
Due to the construction` and shape of the cutting knife 30, a circular cut can be neatly effected during movement of the cutting knife in a direction perpendicular to the plane of the foil.
- f OPERATION The foil web 40 is held in a tensioned planar position between guide roller 8 and transporting rollers 9 and 10. The foil section is tensioned by the action of spring 7 on lever 5 of tensioning roller 6 which is urged to the position shown in solid lines in FIG. 1.
The vertical axis of the machine is also the axis of supports 28, 19, frame parts 29 and 20, circular clamping parts 34 and 15, and of cutting knife 31.
At the beginning of the operation, frame part 20 is located under the tensioned foil portion, and frame part 29 is located above the same, spaced a greater distance and registering with the lower frame part 20. The annular clamping face 180 is located outside of frame part 29 above the tensioned foil portion, registering with clamping face 18 of clamping part 15 which is located under the tensioned foil portion. Springs 36 and 37 hold the cutting means in a position in which the cutting edge is located below the clamping face 180 and adjacent the top face of the tensioned foil section.
Operating motor 26 is started and drives operating member 22 with support 28 downward. The motion is also transmitted by a spring 36 to holder 30 of the cutting means, and by a spring 35 to the upper clamping part 34, and since these parts move simultaneously, the points 38 of cutting edge 31 first reach the tensioned foil and penetrate the same to form holes along a circular line surrounding a circular foil part whose diameter is greater than the diameter of the frame parts 20 and 29.
During further downward movement of operating member 22, clamping face 180 engages the tensioned foil portion of foil web 40 and presses the same against clamping face 18 of the lower clamping part 15. The flanks of the cutting points have somewhat deeper penetrated through the tensioned foil portion, and form spaced slits in the same.
Since springs 35 are weaker than springs 17, the pressure exerted on the foil section by clamping faces 180 and 18 corresponds only to the spring force of springs 35 so that a circular marginal portion of the foil section is frictionally held.
Further downward movement of operating member 22 lowers the cutting edge 31 far enough so that the cutting recesses 39 become effective to complete the circular cut connecting the initial perforations of the foil so that the cutout foil partis only frictionally held by the clamping faces 180 and 18. The downward movement of operating member 22 moves holder 30 of the cutting means to a position in which the upper face of the annular groove 33 abuts the upper edge of the flange 340 of clamping part 34 so that clamping part 34 is rigidly coupled with holder 30, and since springs 36 are stronger than springs 17, further downward movement of operating member 22 moves the lower clamping part 15 downward against the action of springs 17 which results in increased pressure exerted by the clamping faces 18 and 180 on the clamped annular marginal zone of the foil so that the same can not slip between clamping faces 18 and 180.
As best seen in FIG. 4, the clamped marginal portion moves downward ywith clamping means 34, 15 to a position located below the top face of frame part 20 so that an annular framing zone 41a surrounding the central mirror portion 41 is engaged by the peripheral part of frame 20 and tensions the central nip foil portion 41. As shown in FIG. 4, the outer part of the foil section of foil web 40 remains in initial position surrounding cutting knife 31.
During further downward movement of the operating member 22, frame part 29 engages the annular portion of the foil surrounding the frame part 20, and clamps the same by contact of inner surface 29a against outer surface 20a of frame part 20.
The central mirror foil part 41 is now framed by frame parts 20, 29 in a tensioned condition without any folds or wrinkles. Two frame parts 29 and 20 may now be secured to each other in any desired manner.
During the last part of the downward movement of the operating member 22, the marginal zone of the cut-out foil part is pulled out from the clamping end faces and 18, and the outermost part thereof projecting from the gap between the faces 29a and 20a, may be cut off.
Due to rotation of member 25, operating member 22 is again raised so that the finished and framed mirror can be removed from stationary support 19 on which it rests. New frame parts 29 and 20 are mounted on support 19 and 28, and motor 12 is operated to move the foil web 40 a step so that another tensioned foil section is located between the new frame parts 20 and 28.
Springs 17 move clamping part 19 back to its normal higher position shown in FIG. 1, and the springs 37 move the cutting means 30, 31 upward, while clamping part 28 assumes its lower position under the action of springs 35.
FIG. 5 illustrates a modified frame consisting of a frame part 20' and upper frame part 29'. In addition to clamping faces 20a and 29a', an annular groove 42 is formed in frame part 20 into which a rib 43 of frame part 29' projects. The outer margin 41' of the central foil part 41 is laid about rib 43. Reinforcing ribs 46 are provided in the interior yof frame part 20 so that its rigidity is increased. Frame parts 29' and 20 have abutting faces 45, 44 which are preferably welded by ultrasonic vibrations so that the mirror foil is permanently held in the frame 29', 20'.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatus for framing a foil differing from the types described above.
While the invention has been illustrated and described as embodied in method and apparatus for mass-producing framed mirror refiecting foils, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the sprit of the present invention.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:
1. Method of framing a foil portion comprising the steps of tensioning a foil in a plane; making perforations in said foil along an endless line surroundng a foil part; frictionally holding an annular marginal zone of said foil part within said endless line; cutting said foil along said endless line; supporting first and second frame parts on opposite sides of said foil part inward of said frictionally held marginal zone; moving said marginal zone beyond said first frame part so that a central foil portion of said foil part surrounded by said first frame part is tensioned; and moving said first frame part and a second frame part matching said first frame part first into engagement with an annular framing zone of said foil between said marginal zone and said central foil portion, and then into clamping engagement with said first frame portion while pulling said marginal zone out of frictional engagement whereby said central foil portion is framed.
2. The method of claim 1, comprising placing said first and second frame parts on opposite sides of said foil before cutting said foil along said endless line.
3. The method of claim 2, comprising placing said first and second frame parts on opposite sides of said foil after cutting said foil along said endless line.
4. The method of claim 1, wherein said first and second frame parts engage said annular framing zone of said foil before the step of cutting said foil along said endless line.
5. The method of claim 1, wherein said first and second frame parts engage said annular framing zone after the step of cutting said foil along said endless line.
6. The method of claim 1, comprising frictionally hold- 3,180,220 4/ 1965 Jeree 160--37 8 ing said marginal zone during cutting of said foil, and frm- 3,243,042 3/1966 Moulton 209 403 1y clamping saici marginal zone during tensioning of said 3,286,338 11/1966 Bohr 29 446 central foll portion; and Wherem the tensioned larea of the foil is substantially greater than said central foil portion. 5 3291164 12/1966 Swallow 29""449 X References Cited CHARLIE T. MOON, Primary Examiner UNITED STATES PATENTS U S CL XRl 173,720 2/1876` Guerin. i60-378 2,961,759 11/1960 Weissfloch 29-452 10