US2717626A - Apparatus for producing edge compression stresses in metal strips - Google Patents

Description

Sept. 13, 1955 LIEICEIRWOO 2,717,626

- .L. APPARATUS PROD NG EDGE MPRESSION SSES IN ME ST I S STRE Filed March l9 1 N V EN TOR. fi/K/W? A ffla/zvaad Wm M United States PatentO 1 2,717,626 APPARATUS FOR PRODUCING EDGE COM- PRESSION STRESSES IN METAL STRIPS Glenn L. Sherwood, Benton Harbor, Mich., assignor of one-third to Henry L. Johnson and one-third to Ferdinand J. Thar, Benton Harbor, Mich.

Application March 9, 1951, Serial No. 214,748

6 Claims. c1. 1s3-32 This invention relates to improvements in method and apparatus for producing compression stresses in the edges of an elongated flexible metal strip and stock produced thereby.

The main objects of this invention are:

First, to provide an apparatus for producing compression. stresses in the edges of an elongated metal strip whereby the strip is rendered suitable for the forming of slats for Venetian blinds and the like and may be cross sectionally curved or conformed and the shape thereof is maintained without twist or camber.

Second, to provide an apparatus for producing compression stresses in the edges of an elongated flexible metal strip which does not result in the disfiguring or substantial marring of the surface of the strip.

Third, to provide a method of producing compression stresses in the edges of an elongated metal strip resulting in a strip which is well adapted for use as stock in the forming of Venetian blind slats and the like of curved or other nonplanar cross section.

Fourth, to provide a strip of rolled metal stock suitable for use in the forming of Venetian blind slats and like parts.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is pointed out in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary side elevational view of an apparatus embodying my invention and well. adapted for the practicing of the method of my invention.

Fig. 2 is an enlarged fragmentary view looking from the right of Fig. 1 and partially in vertical section on a line corresponding to line 22 of Fig. 3.

Fig. 3 is a fragmentary view in section on a line corresponding to line 3-3 of Fig 2.

Fig. 4 is a plan view of a strip of thin metal stock to be processed.

Fig. 5 is a plan view of the processed stock or stock after it has been passed through the apparatus of my invention.

Fig. 6 is an edge view thereof.

In the accompanying drawing 1 represents the stock to be treated or processed to produce compression stresses in the edges thereof, 100 the strip after processing with the bulges or distortion 101 therein resulting from the compression stresses produced in the edge of the strip by passing the stock through the apparatus. It will be understood that the distortions 101 between the edges,as illustrated, are very greatly exaggerated and they are shown as being alternately and. quite uniformly disposed; and while they usually are more or less uniformly disposed the metal strip illustration is for the purpose of illustrating that the edges of the strip have compression stresses set up therein and that there is no longitudinal stretching of the center portion of the strip.-

The numeral 2 represents the roll of stock and 3" the roll of stock after processing.

The apparatus illustrated is especially designed for use in the producing of stock suitable for use in the making or formingof slats for Venetian blinds; As an. example, the strip of stock may be cold rolled steel 2" wide by .008 thick. This is a dimension or approximate dimension suitable for Venetian blinds such, for example, as are 2,717,626 Patented Sept. 13, 1955 used in homes. The apparatus may be used for the processing or treating of wider and thicker stock for slats and other uses but in that case, the dimensions of the parts are increased to correspond with the width of the stock treated.

The apparatus of the embodiment illustrated comprises a suitable base 4 which may be bolted or otherwise secured to a table or bench and which is provided with spaced bearing uprights 5 provided with bearings 6 for the spindle 7 of the pulley 8. The spindle 7 rotates freely in the hearings or if preferred, the pulley 8 may rotate on the spindle. The pulley 8 is crowned and provided with guide flanges 9 at its ends. The strip of stock 1 is passed or translated around the pulley with a substantially U-shaped bend, the guide pulleys 10 and 11 being arranged so it is guided to and around the pulley to form the U-shaped bight 12 therein which is in supported engagement with the center of the crown of the pulley as is shown in Figs. 1 and 3.

The means for winding the stock on the spool 13 or the brake means for the spool 14 of the supply roll 2 are not illustrated but it is desired to point out that only suificient tension on the strip is required to keep the bight 12 of the U-bend of the stock in taut or close supporting engagement with an arc of the pulley. As the strip is translated around the pulley, the bight portion 12 thereof is transversely bent and the central part thereof urged against the crown of the pulley by means of the shoelike supporting members 15 which have curved work supporting edges 16, desirably inwardly beveled. The work engaging faces of these members 15 are disposed at a radial distance from the axis of the pulley substantially less than the radius of the pulley at the center of its crown but the surfaces 18 are spaced from the pulley so that the edges of the strip are not clamped against the pulley but are supported in diverging relation to the surfaces of the pulley as is shown in Fig. 2.

The members 15 are mounted on a support 17 pivoted at 171 at one side of the pulley 8 and adjustably supported by the screw 19 which engages the base and is provided with a handwheel 20 for convenience in adjustment. With this arrangement, the portion of the strip passing around the pulley is transversely conformed as shown in Fig. 2. This results in producing compression stresses in the edges of the flexible strip which adapts it for use in the forming of various parts but as stated, it is particularly adapted as stock for the forming of Venetian blind slats and also Venetian blind slats of curved or other nonplanar cross section.

The strip treated is not subjected to stretching or other stresses which substantially distort or tend to distort the granular structure thereof but compression stresses are produced in the edge portions sufficient to prevent or minimize twisting distortions when the treated stock is formed into Venetian blind slats or the like. As stated,-

the only sufiicient longitudinal stress or tension is required on the strip of stock 1 to translate it around the pulley and keep it sufiiciently taut to maintain it in supported engagement with a substantial arc of the crowned pulley. The treated or processed stock is not transversely curved as is the portion illustrated, passing around the pulley in an operative relation to the members 15 but issues from the apparatus substantially flat, but may be subjected to treatment by known means to remove camber if that is deemed desirable.

I have illustrated and described my inventionin a simple but practical embodiment thereof and in an apparatus that may be usedin the practicing of my method. I have not attempted to illustrate more complete mechanisms which might be desired in commercial production as it is believed that this'disclosure will enable'those skilled in the art to embody or adapt my invention as may be desired.

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

1. An apparatus for producing compression stresses in the edges of an elongated resilient metal strip comprising a supporting frame, a crowned pulley journaled on said frame for free rotation, means for guiding and translating a metal strip endwise around said pulley in a longitudinally curved form With a portion of the strip intermediate its edges in interiorly supported engagement with the crown of the pulley and with edge portions of such longitudinally curved portion of substantial width projecting laterally beyond such interiorly supported intermediate portion of the strip and being interiorly unsupported, and exterior support members for such interiorly unsupported edge portions of the strip mounted on said frame for adjustment relative to the axis of the pulley and having curved work engaging faces in exterior supported engagement with interiorly unsupported edge portions of the strip throughout a substantial arc of the bend thereof, the work engaging faces of the support members being spaced a radial distance from the axis of the pulley substantially less than the radius of the pulley at the work engaging surface thereof so that edge portions of a substantial arc of the longitudinally curved portion of the strip supportedly engage said support members and the strip is transversely curved simultaneously with the longitudinal curving thereof resulting from its translation around the pulley.

2. An apparatus for producing compression stresses in the edges of an elongated resilient metal strip comprising a supporting frame, a crowned pulley journaled on said frame for free rotation, means for guiding and translating a metal strip endwise around said pulley in a substantially U-bent form with a portion of the U-bend intermediate its edges in interiorly supported engagement with the crown of the pulley and with edge portions of the U-bend of substantial width projecting laterally beyond such interiorly supported intermediate portions of the strip with said edge portions interiorly unsupported, and exterior support members for such interiorly unsupported edge portions of the strip mounted on said frame for adjustment relative to the axis of the pulley and having beveled work engaging faces in exterior supporting engagement With the interiorly unsupported edges of the strip throughout a substantial arc of the bend thereof and so that a substantial arc of the interiorly unsupported edge portions of the U-bent portion of the strip lappingly engage the said faces of said support members and the U-bent portion of the strip is transversely curved simultaneously with the longitudinal curving thereof resulting from its translation around the pulley.

3. An apparatus for producing compression stresses in the edges of an elongated resilient metal strip comprising a supporting frame, a pulley journaled on said frame for free rotation, means for guiding and translating a metal strip endwise around said pulley in a substantially U-bent form with a portion of the U-bend intermediate its edges in interiorly supported engagement with the peripheral face of the pulley and with edge portions of the U-bend of substantial width projecting laterally beyond such interiorly supported intermediate portion of the strip with said edge portions interiorly unsupported, and exterior support members for such interiorly unsupported edge portions of the strip mounted on said frame for adjustment relative to the axis of the pulley and having curved beveled work engaging faces in exterior supporting engagement with the interiorly unsupported edges of the strip throughout a substantial arc of the bend thereof so that a substantial arc of the interiorly unsupported edge portions of the U-bent portion of the strip lappingly engage said support members and the U-bent portion of the strip is transversely curved simultaneously with the longitudinal curving thereof resulting from its translation around the pulley.

4. An apparatus for producing compression stresses in the edges of an elongated resilient metal strip comprising a supporting frame, a pulley journaled on said frame, means for guiding and translating a metal strip endwise with a central portion thereof curvedly bent around and in interiorly supported engagement with a substantial arc of the pulley and with edge portions of the strip of substantial Width out of contact with the pulley and projecting laterally beyond said interiorly supported portion of the strip and being interiorly unsupported, and laterally spaced exterior support members for the interiorly unsupported edge portions of the strip adjustably mounted on said frame and having outwardly curved faces engaging edge portions only of the strip in laterally spaced relation to the portion of the strip in interiorly supported engagement with said pulley, the curved faces of said exterior support members being spaced a radial distance from the axis of the pulley substantially less than the radius of the strip engaging portion of the pulley, the edge portions of the strip being urged upon the said exterior support members only by the inherent resilience of the strip resulting from the transverse curving of the arcuate portion thereof while in interior supported engagement with the pulley.

5. An apparatus for producing compression stresses in edge portions of an elongated metal strip comprising a supporting frame, a crowned pulley rotatably mounted on said frame, means for guiding and translating the strip around said pulley with an intermediate portion of the strip in interiorly supported engagement with the pulley and longitudinally curved around a substantial arc thereof and with edge portions of the strip of substantial width interiorly unsupported for free flexing radially of the pulley, and exterior support members for said interiorly unsupported edge portions of the strip adjustably mounted on said frame and having curved work engaging surfaces spaced laterally from the work engaging are of the pulley and in exterior supported engagement with substantial arcs of the interiorly unsupported edge portions of the work, the work engaging surfaces of said exterior support members being spaced a radial distance from the axis of the pulley substantially less than the radius of the pulley at the work engaging crown thereof.

6. An apparatus for producing compression stresses in edge portions of an elongated metal strip comprising a supporting frame, a pulley rotatably mounted on said frame, means for guiding and translating the strip around said pulley with an intermediate portion of the strip in interiorly supported engagement with the pulley and longitudinally curved around a substantial arc thereof and with edge portions of the strip of substantial width out of contact with the pulley and interiorly unsupported for free flexing radially of the axis of the pulley, and exterior support members for said interiorly unsupported edge portions of the strip mounted on said frame and 1: having arcuately curved work engaging surfaces spaced laterally from the Work engaging arc of the pulley and in exterior supported engagement with substantial arcs of the interiorly unsupported edge portions of the work,

n the work engaging faces of said exterior support members being spaced a radial distance from the axis of the pulley substantially less than the radius of the pulley at the work engaging surface thereof.

References Cited in the file of this patent UNITED STATES PATENTS 135,150 Pearce Jan. 21, 1873 471,407 Westaway Mar. 22, 1892 902,031 White Oct. 27, 1908 1,032,907 Hyde July 16, 1912 1,937,663 Norton Dec. 5, 1933 1,963,724 Taylor June 19, 1934 2,076,458 Hall Apr. 6, 1937 2,156,163 Pierce Apr. 25, 1939 2,263,540 Johnson Nov. 18, 1941 2,600,442 Stanius June 17, 1952

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