US2088570A - Wire feeding mechanism - Google Patents

Description

B. B. BLANCHARD 2,088,570

WIRE FEEDING MECHANISM Filed April 27 1936 Aug. 3, 1937.

3 Sheets-$heet 1 BM 6 W Aug. 3, 1937.

' B. B. BLANCHARD 2,088,570 WIRE FEEDING MECHANISM Filed April 27, 1956 s Sheets-Sheet? 1"" E lgrZ.

T 56 vE/vmQ Q I @SLAW Aug. 3, 1937. B. B. BLANCHARD WIRE FEEDING MECHANISM Filed April 27, 1936 5 Sheets-sheaf s //v l/f/V 70/1 7 Hi -m/ah.%silm Patented Aug. 3, 1937 UNITED STATES 2,088,570 WIRE FEEDING MECHANISM Benjamin B. Blanchard, Swampscott, Mass, as-

signor to United Shoe Machinery Corporation, Paterson, N. J., a corporation of New Jersey Application April 27, 1936, Serial No. 76,555

8 Claims.

This invention relates to wire feeding mechanism and is illustrated as embodied in a machine of i the type shown in United States Letters Patent No. 1,839,238, granted January 5,

1932, on the application of F. L. MacKenzie.

The machine mentioned has for its purpose the formation, and driving into a work piece, of wire staples. In the MacKenzie machine a wire is drawn from a reel by the rotation of a pair of feed wheels between which it is held and its end is thrust over an inside former, which is simply a metallic abutment having its thickness substantially equal to the distance between the insides of the legs of the staple to be formed and driven. An outside former, which is of inverted U-shape, is then'driven down over the wire piece, which has just previously been cut from the body of the Wire by a pair of knives, and bends it into a two-legged staple, The inside former is then withdrawn, leaving the staple frictionally held in the outside former, in driving position, after which a driver descends through a suitable channel in the outside former and. forces the staple down through a driving throat into a work piece held between the throat and a clinching anvil movable to hold the work against the throat.

The length of the legs of the staple is determined by shifting the feed wheels and the knives toward or from the axis of the driver and inside former, and altering the rotary feeding movement of the feed Wheels accordingly. For example, if the staple legs are desired to be A," longer than those of the staples for which the machine is then set, the feed wheels and knives are moved farther from the axis of the inside former and the feeding movement of the wheels is changed to feed A" more wire. The machine thus far described antedated the invention of MacKenzie, the shifting of the feeding and cutting mechanism being theretofore accomplished by means of a hand lever and cam which broughtabout the above-described change in position of the feed wheel rotating shaft such that the length of wirefed was thereby varied. Such a machine is shown in United States Letters Patent No. 1,016,930, granted February 13, 1912, on the application of W. H. Borden.

The invention of MacKenzie, described and claimed in the above-mentioned patent, rendered the shifting of the feed wheels and knives automatic by operating it in connection with the upward movement of the clinching anvil through which the work was clamped between this anvil and the driving throat, so that the changes in the lengths of the staple legs were determined by the changes in the thickness of the work, thus avoiding difiiculty resulting from failure of the operator of the Borden machine to change the wire feed when he should. The MacKenzie machine, however, left unchanged the feed Wheel rotating device of Borden, which was subject to considerable inaccuracy in use due to looseness resulting from wear, to which the mechanism was highly sensitive.

It is a principal object of the present invention to correct this difiiculty, and I have accordingly provided a mechanism for effecting and regulating the wire feed which avoids the defects of the Borden mechanism, which is positive and accurate in operation, and which retains the advantageous characteristics of both the Borden and MacKenzie machines.

To this end I have provided a novel staple forming organization having a wire feeding means operated by an arm having a fixed throw, irrespective of the length of the staple being formed, in which the operative connection between the arm and the feeding wheel consists of a single link and crank arm connection, a construction having minimum susceptibility to wear.

In accordance with another feature of the invention I have provided means for correcting minor inaccuracies in the said link and crank arm mechanism, when rigorous accuracy is desirable. This is done by means of a cam control for regulating the length of the crank arm in accordance With the movement between the anvil and throat which, as in the MacKenzie machine abovementioned, efiects the desired shifting of the feed wheel slide.

These and other features of the invention comprising certain combinations and arrangements of parts will be apparent from the following description of a preferred embodiment of the invention shown in the drawings, in

Fig. 4 is an expanded perspective view of the mechanism shown in Fig. 3. i

As suggested above, the illustrated machine is similar to the machine of the MacKenzie patent cited, in all respects except the wire feeding mechanism, and the MacKenzie patent should be consulted for a full description of the main dently much larger than the former.

part of the mechanism. Fig. 1 herein is a view corresponding to Fig. 3 of the MacKenzie patent.

The main shaft It, the carrier 54, sliding on two rods 58, with its feed wheel 44, the release lever 50 which carries a cooperating presser roll (herein numbered 52) the operating lever 80 for the feeding device, pivoted at I3, and its cam roll 82 and cam track 84 mounted on the shaft I6, the vertically movable anvil or clinching abut ment I08, the screw H2 carried by it, the bellcrank lever I22 pivoted at IIB, with its stud I24, cooperating with the screw IIZ when the abutment I08 is raised, in order to operate the rack I38 which slides the carriage 54 on the rods 58, in accordance with the thickness of the work between the driving throat I40 and the abutment I08, all operate as described in the MacKenzie patent above mentioned, and the anvil I08 is raised by a treadle to clamp the work against the throat I40, as shown in the patent. All the ele ments mentioned (except 52) are numbered as in the MacKenzie patent.

The novel mechanism for operating the feed wheel 44 will now be described. The wheel 44 is integrally mounted, i. e., rigidly fastened, on a shaft 50, pivoted in the sliding carrier 54, and the shaft carries an integral crank arm I30 at its rear end. The lever I30v carries a toothed segment I32 at its lower end cooperating with a toothed segment I34 keyed on one end of a shaft I36 rotatable in the machine frame I0 (Fig. 2). The shaft '30, being mounted in the sliding carrier 54, can assume a variety of positions relatively to the shaft I36. The shaft I36 has an arm I30 mounted on its end remote from the segment I 34, and a simple link I4! pivotally connects the arm I39 and the arm I30, at the points I42, I44, respectively.

The lever 80, being controlled by the cam 34, has a fixed throw, irrespective of the length of the staple being formed, and so, therefore, have the segment I34 and the arm I39. The movement of the center I44, arm I30 and shaft 60, due to the pull of the link I4I, as the arm I30 swings from the position I 3E! shown in Figs. 1 and 3, to the position I30 (Fig. 3) depends on the position of the carriage I0 and the shaft 60.

This is illustrated in Fig. 3, which shows the mechanism in three-positions as set for staples of three diiferent lengths. The arm I39 is shown in its two extreme positions, I39 and I39 corresponding to the beginning and ending of the feeding movement. The link MI is shown in two full line positions, I II and I M corresponding to its positions at the beginning and ending of the feed for a short-legged staple, the center of the shaft 60 being then at 60. For a longlegged staple, the center 60 is moved to 00 and. the initial and final positions of the link I4I are shown in full lines at I M and I4I respectively. The wire feed is proportional to the angles measured by the arcs M -I44 and M l -444 whose centers are at 60 and 60, respectively, in the two cases, and the latter is evi- Fig. 3 is illustrative, merely, and is not drawn carefully to scale.

It is obvious that the amount of wire fed depends only on the initial and final positions of the arm I30, it being immaterial just how the arm I30 gets from one position to the other. It-may be remarked that it is quite simple to design the machine to deliver exactly the amounts of wire requisite for staples of two lengths of leg. It will Elbe, remembered that the center 60 is to slide by an amount exactly equal to the desired difference in length of the staple leg, and that the feed wheel 44 is then to feed twice as much more wire as this for the longer staple as for the shorter. The center 60 is laid out on the slide axis 58 (Fig. 3) at 60 and 60 and the arcs M l -I44 and I44I 44 are laid ofi symmetrically relatively to the axis 58. These arcs are computed from the radius of the feed wheel 44 and the desired total lengths of wire. Arcs are then struck from these four points I44, with radii all equal to the length of the link I4I, which will locate the two points I42 and I42 The center I35 is the intersection of the axis 58 with the perpendicular bisector of the line I42 -I42 This layout will make the machine feed exactly right for the longest and shortest staples. It was found, however, thatwhile it would deliver the proper lengths of staple wire in the cases of staples of the maximum and minimum lengths for which the machine was intended, it would deliver a little too much wire (arc M l -444 Fig. 3) for a staple of medium length, and owing to the method by which the staples are formed such error in the length of the wire would make the legs of the staple of correspondingly unequal length.

In accordance with the present invention this olifliculty is corrected by a change in the described construction of the arm I30. The arm I30 is formed with a longitudinal slot I45 (Figs. 1 and 4) in its end, the pivot pin at I44 being located in and fitting this slot. The position of the pivot pin at I44 in the slot I45 is controlled by a link I45 (Figs. 1 and 3) joining the pin and the vertical arm I50 of a lever, shown as a bell crank, pivoted at I5I on an arm running down from the carriage 54, and having a horizontal arm I52 the end of which rests in a cam slot I54 formed in a stationary cam I50 mounted on a bracket I58 carried by the frame I0 of the machine. The positions I44 and NW which will give an arc of the required length may be found empirically by the designer (the center 00 remaining undisturbed), and the requisite position of the bell crank I50, I52, and the requisite point I50 (Fig. 3), of the cam slot I54, determined in consequence. Only one point on the cam I54 will correspond to a given length of staple leg since the pivot I5! moves with the carriage 54, so that the shifting of the center 60 in accordance with the thickness of the work will determinethe proper length of staple in all cases.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a staple forming and driving machine, a wire feeding mechanism comprising an arm having a fixed throw irrespective of the length of staple being formed, a wire feeding wheel having an axis shiftable relatively to the pivotal axis of the said arm to vary the effect of the throw of the said arm on the wire feeding wheel, said feeding wheel having also an integral crank arm,

and a link connecting the two said arms.

2. In a staple forming and driving machine, a wire feeding mechanism comprising an arm having a fixed throw irrespective of the length of staple being formed, a wire feeding wheel operated by the said arm and having an axis shiftable relatively to the pivotal axis of the said arm to vary the effect of the throw of the said arm on the wire feeding wheel, and mechanism controlled by the thickness of the work in the machine for determining the position of the said shiftable axis.

3. In a staple forming and driving machine, a wire feeding mechanism comprising an arm having a fixed throw irrespective of the length of staple being formed, a wire feeding wheel having an arm linked to said first-mentioned arm and having an axis shiftable relatively to the pivotal axis of the said first-mentioned arm to vary the effect of the throw of the said first mentioned arm on the wire feeding wheel, and mechanism controlled by the thickness of the work in the machine comprising a slide on which the said shiftable axis is mounted.

4. In a staple forming and driving machine, a driving throat and an anvil, one of which is movable to grasp a work piece between them, a wire feeding mechanism, means for operating the feeding mechanism, said feeding mechanism being shiftable relatively to the operating means to vary the feeding effect of said operating means on the feeding device, and mechanism for refining said variation of the feeding effect comprising a crank arm of variable length, a lever having one arm connected to the feeding device to vary the length of said crank arm, and a cam controlling the other arm of said lever.

5. In a staple forming and driving machine, an am having a fixed throw, a wire feeding wheel having an integral arm, a link connecting said two arms, a movable member in which said feeding wheel is mounted, whereby the rotative effect of said fixed throw upon said feeding wheel can be varied, a movable work grasping element, a

lever connected to said movable member and operated by the movement of the said work grasping element, and means, comprising a cam, operated by the last-mentioned movement, for varying the effective length of the arm on the feeding wheel to vary the effect of the firstmentioned arm upon the feeding wheel.

6. In a staple forming and driving machine, an arm having a fixed throw, a wire feeding wheel having an integral arm, a link connecting said two arms, a movable member in which said feeding wheel is mounted, whereby the rotative effect of said fixed throw upon said feeding wheel can be varied, a movable work grasping element, a lever connected to said movable member and operated by the movement of the said work grasping element, and means operated by the lastmentioned movement for altering the effective length of the second said arm.

7. In a staple forming and driving machine, an arm having a fixed throw, a slide, an anvil, and

a driving throat arranged to be moved relatively toward each other to grasp a,-work piece, mechanism for moving said slide controlled by said relative movement, a wire feeding wheel mounted on said slide and having a crank arm, a link connecting said arm to said crank arm, the connection between said link and crank arm being of pin-and-slot .form, and a cam and connections for moving the pin in the slot as said slide moves.

8. In a staple forming and driving machine, an arm having a fixed throw, a slide, an anvil, and a driving throat arranged to be moved relatively toward each other to grasp a work piece, mechanism for moving said slide controlled by said relative movement, a wire feeding wheel mounted on said slide and having a crank arm with a slot in its outer end, a link pivoted at one end to said arm and having a pin fitting in said slot at its other end, a lever mounted on the said slide, a link connecting one arm of the lever to said pin whereby the effective length of the crank arm having the slot may be varied, and a cam controlling the position of the other arm of said lever.

BENJAMIN B. BLANCHARD.

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