Sensor construction for coil stock cradles and the like
United States Patent 1 1 St. Sauveur Apr. 29, 1975 [75] Inventor: Omer G. St. Sauveur, Holyoke.  
 Mass.  
 [73] Assignee: Carl C. Peterson Co., Inc., Esmond,  
 [22] Filed: Jan; 2, 1974 211 Appl. No.: 429,503  
 Primary Examiner-Edward J. McCarthy Attorney, Agent, or Firm-Salter &amp; Michaelson [57] ABSTRACT A sensor construction for coil stock cradles and the like wherein strip stock is intermittently fed from a source of supply and wherein a sensor is engaged by the stock when a minimum predetermined amount of slack ceases to exist, said engagement actuating the feed means. The sensor construction embodies a pair of elongated rod portions in spaced relation to each other, whereby if the rod portion which is engaged by the stock should break, the second rod portion would still be present to effect the desired sensing action. The sensing rod is convexly curved at the point where it makes engagement with the strip stock whereby the opposite edges of the strip are spaced from the rod when the rod is making engagement therewith.  
 6 Claims, 3 Drawing Figures PATENTEDAPRZQIHIS SHEET 10F 2 FIG.|  
 SENSOR CONSTRUCTION FOR COIL STOCK CRADLES AND THE LIKE BACKGROUND AND SUMMARY OF THE INVENTION This invention relates generally to coil stock cradles and more specifically to cradle feeders wherein strip metallic stock is intermittently fed from a coil or roll to a point of use, such as a power press or the like. The intermittent feed is traditionally controlled by sensing means engaged by the strip when a predetermined minimum amount of slack exists therein. Thus, as the strip is drawn from the cradle by operation of the power press or the like, the sensing means will be engaged by the strip when a predetermined minimum amount of slack exists therein to again actuate the feed means to feed or pay out more strip. Thus. a sufficient amount of strip is always dispensed or uncoiled to permit smooth and uninterrupted operation of the power press. Coil stock cradles of the type just discussed are disclosed and described in copending application Ser. No. 181,392, filed Sept. 17, 1971, and also in US. Pat. Nos. 2,692,737; 2,789,777; and 3,223,344.  
  It has been found desirable in cradle feeders of this type to have the sensing means in the form of an elongated rod that extends transversely of the strip well beyond opposite edges of the latter. Sensing means of this type are shown and described in the aforesaid copending application Ser. No. 181,392. If has been found, however, that over a period of time, the intermittent engagement of the strip with the feeler rod results in a shearing action taking place on the rod at the point where the opposite edges of the strip engage the rod, which shearing action creates the likelihood of the rod becoming severed at one or both of these points, thereby rendering the sensing means ineffective. If this breakage or severing takes place while the cradle is in operation and is not noticed, proper feed of the strip from the coil will cease to take place, thereby raising the possibility ofjamming or other harm being done at the power press or the like to which the stock is being fed. The present invention is directed to a sensor construction which overcomes this problem in two different ways.  
  First of all, the sensor construction of the present invention, rather than embodying a single elongated rod, as in copending application Ser. No. 181,392, embodies a pair of spaced rods so arranged that when the sensor is engaged by the strip, only one of the rods will be engaged. the other rod being spaced from the point of engagement. Thus, if the rod that is engaged by the strip should eventually become severed or broken, the second rod is automatically present to effect the desired sensing action. This affords sufficient time for the breakage or severing of the first rod portion to be noticed so that new sensing means may be installed without any interruption or damage to the cradle apparatus or the power press which may be associated with said apparatus.  
  The second feature of the present invention is to provide means whereby the likelihood of the sensing rod being severed by the edges of the strip stock is greatly lessened. This is accomplished by bowing the rod portion that is engaged by the stock so that the rod is convexly curved with respect thereto whereby the opposite edges of the strip will be spaced from the rod when engagement is made. Since it is the edge contact of the strip with the rod that contributes most significantly to severing of the rod, it will be seen that by eliminating or at least reducing this edge contact, the likelihood of severing is likewise eliminated or at least reduced.  
  Other features and advantages of the present invention will become obvious as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.  
 DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the best mode presently contemplated for carrying out the present invention;  
  FIG. 1 is a fragmentary elevational view showing sensing means constructed in accordance with the present invention in operative position in a coil stock cradle;  
  FIG. 2 is a top plan view of the sensing means assembly; and  
  FIG. 3 is an exploded perspective view showing the important components of my novel sensing means.  
 DESCRIPTION OF THE INVENTION Referring now to the drawings, and more particularly FIGS. 1 and 2 thereof, a portion of a coil stock cradle is shown embodying a vertically disposed side wall 10 having a support rod 12 and a support bracket 14 secured to the inner surface thereof and extending across to an opposite side wass (not shown). The cradle comprises conventional coil support and feed means (not shown), from which an elongated strip of stock 16, usually metallic, is intermittently fed to a point of use, such as a power press or the like (not shown). It will be understood that the construction and operation of the coil stock cradle per se forms no part of the present invention and hence requires no further description, although such apparatus is fully disclosed and described in copending application Ser. No. 181,392.  
  Pivotally secured to side wall 10, as by the mounting assembly 18, is an upwardly extending post 20 having slidably mounted thereon a block 22, the vertical position of which may be adjusted by set screw 24. Slidably extending through the block 22 in a lateral direction toward the opposide side wall of the cradle is a rod 26, the lateral position of which may be adjusted by a set screw (not shown). At its inner extremity, by a suitable bracket 28, rod 26 carries switch means 30, the actuating shaft 32 of which fixedly carries sensor block 34. As will be seen most clearly in Fig. 3, block 34 is provided with a split aperture 36 which clampingly receives shaft 32. It will be understood that the pivotal mounting of post 20, in combination with slidable block 22 and slidable rod 26, permit universal adjustment of the sensing or feeler assembly, so that the sensing means, new to be described, may be adjusted to any desired position.  
  As will be seen most clearly in Fig. 3, the block 34 is provided with a pair of spaced grooves 38 which are adapted to receive opposite ends of sensing rod 40. As will be noted, the sensing rod 40, which is of any suitable metallie construction, comprises an elongated rod that is reversely bent as at 42 whereby to provide a first rod portion 44 and a second rod portion 46. Due to the bend 42, and the resilience of the rod 40, when the free ends of rod portions 44 and 46 are clamped in the grooves 38, the rod automatically assumes the bowed configuration illustrated in FIG. 1. As will be seen in FIG. 3, a clamping plate 48 overlies grooves 38 and is secured to block 34, as by screw 50, to clamp the rod 40 to the block 34.  
  As will be seen most clearly in FIG. 1, the sensing rod 40 extends transversely of strip 16 and substantially beyond opposite edges 52 of the latter. Block 34 is oriented so that when insufficient slack exists in strip 16, the strip will engage first rod portion 44, at which point second rod portion 46 is in spaced relation therefrom. It will thus be clear that if as a result of repeated engagement between strip 16 and first rod portion 44 the latter should become worn as a result of friction and eventually sever or break, second rod portion 46 will still remain to effect the desired sensing function. It is important to note that the convex curvature of first rod portion 44 minimizes contact between said rod portion and strip 16, whereby the opposite edges 52 of the strip are actually spaced from rod portion 44, as clearly illustrated in FIG. 1. This eliminates the shearing tendency which normally exists where the sensing rod is substantially straight, in which case the relatively sharp edges 52 of the strip make repeated engagement with the sensing rod, thereby creating a shearing action which greatly reduces the life of the rod.  
  It will, of course, be understood that when the sensing rod 40 is engaged by the strip 16, pursuant to predetermined diminution of the slack or loop in the strip, the rod will be forced downwardly to rotate shaft 32, which in turn actuates switch 30, which, through suitable wiring 54, energizes the motor means (not shown) in the cradle to commence feed of the stock until sufficient slack again exists.  
  Although sensing means embodying the present invention have prime utility in connection with coil stock cradles, and have been shown and described in such an environment, it will be obvious that the present invention is also applicable to other types of apparatus where sensing means are used to detect tension in a strip of some kind, in response to which-some other means are actuated.  
  While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modificaions and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.  
 What is claimed is:  
 1. ln apparatus of the type wherein strip stock is intermittently fed, said intermittent feed being actuated by sensing means. said sensing means extending transversely of said strip and being positioned so as to be engaged thereby when a predetermined minimum slack exists in said strip, said sensing means comprising a first elongated rod portion extending transversely of said strip and extending substantially beyond the opposite edges thereof, a second rod portion also extending transversely of and substantially beyond the opposite edges of said strip, means mounting said rod portions so that said first portion only is engaged by said strip when the predetermined minimum slack exists therein, said second portion being adjacent to but spaced from said strip when the latter engages said first portion, whereby if said first portion breaks, said second portion will actuate said intermittent feed.  
  2. The sensing means of claim 1 further characterized in that said first rod portion is convexly bowed, whereby when said first portion engages said strip, the opposite edges of the latter are spaced therefrom.  
  3. The sensing means of claim 1 further characterized in that said mounting means comprises a block having a pair of spaced grooves extending in a direction transverse to the direction of travel of said strip, said grooves each receiving one of said rod portions therein, and a plate overlying said grooves and removably secured to said block to clamp said rod portions in said grooves.  
  4. The sensing means of claim 3 further characterized in that said rod portions comprise one integral reversely bent member, the opposite ends of which are clamped in said grooves.  
  5. The sensing means of claim 4, said first and second portions being outwardly bowed with respect to each other, the edge of said first portion that engages said strip being convexly bowed, whereby the opposite edges of said strip are spaced from said first rod portion when the latter engages said strip.  
  6. In apparatus of the type wherein strip stock is intermittently fed, said intermittent feed being actuated by sensing means, said sensing means extending transversely of said strip and being positioned so as to be engaged thereby when a predetermined minimum slack exists in said strip, said sensing means comprising an elongated rod portion extending transversely of said strip and extending substantially beyond the opposite edges of said strip, said rod portion being convexly bowed whereby when engaged by said strip, the opposite edges of the latter are spaced therefrom.