US2767411A

US2767411A - Nail making machine

Info

Publication number: US2767411A
Application number: US249436A
Authority: US
Inventors: Jr Frank A Clary; Grant N Willis
Original assignee: Pittsburgh Steel Co
Current assignee: Pittsburgh Steel Co
Priority date: 1951-10-03
Filing date: 1951-10-03
Publication date: 1956-10-23
Anticipated expiration: 1973-10-23

Description

Oct. 23, 1956 F. A. CLARY, JR, ET AL NAIL MAKING MACHINE 6 Sheets-Sheet 1 Filed Oct. 5, 1951 INVENTORS FRANK A.CLARY}JR. GRANT I'LWILLIS BY fi e 7k ATTORNEY Oct. 23, 1956 F. A. CLARY, JR. ET AL 2,767,411

' NAIL MAKING MACHINE Filed Oct. 5', 1951" e Sheets-Sheet 2 rum heads nail qnppers start to open qrippel; ckum contlnct: roll o Iv -feed carriage on dead center :1 es up s cc 59'-knives fullyppenwire feeding rum movlnq in mm moving out knives opening-- 270' ejector strikes noil 4 v knives cu't null 239' wire feed ends knives touch wire grippers touch wire rem retracted wire feeding INVENTORS FRANK A.0LARY an. GRANT u. vnLus ATTORNEY Oct. 23, 1956 F. A. CLARY, JR., ET AL NAIL MAKING MACHINE 6 Sheets-Sheet 3 Filed 001;. s. 1951 s m T N E V m FRANK A.CLARY, JR. GRANT N. WILLIS Q 7M4 ATTORNEY Oct. 23, 1956 F. A. CLARY, JR. ET AL 2,767,411

NAIL MAKING MACHINE Filed Oct. 3. 1951 6 Sheets-Sheet 4 H M as as WJIL LEL 34 3836 V 64 so s a e 6 INVENTORS FRANK A.CLARY, JR. GRANT N.VIILLI$ KITORNEY Oct. 23, 1956 F. A. CLARY, JR., ET AL NAIL MAKING MACHINE 6 Sheets-Sheet 5 Filed Oct. 5. 1951 INVENTORS FRANK LCLARY JR. en T a. vnLu BY A416; 7% 2 4M ATTORNEY Oct. 23,1956 F. A. CLARY,IJR ET AL 2,767,411

NAIL MAKING MACHINE Filed Oct. 3. 1951 s Sheets-Sheetfi 'mvsu'rons FRANK A-CLARY,'JRI

08%1' ".WILLIS mbnusv United States Patent Ofiice 2,767,4 ll Patented Get. 23, 1956 2,767,411 NAIL MAKING MACHINE Frank A. Clary, Jr., and Grant N. Willis, Bristol, Cnn., assignors to Pittsburgh Steel Company, Pittsburgh, Pa., a corporation of Pennsylvania Application (Pctober 3, 1951, Serial No. 249,436 13 Claims. (CI. 10-49) The present invention relates to machines for making wire nails and has for its principal object the provision of a machine capable of operating safely at a higher speed of production than has heretofore been possible with machines of the same general type.

The machine of the present invention is of the type in which wire from a suitable source of wire supply is fed into a gripping device which tightly holds the wire during the formation of a head which is swaged down against the gripping device by means of a reciprocating ram. After the formation of the head, the gripping device opens and the wire is fed forward a distance corresponding to the length of the nail to be made, whereupon the nail is cut off and ejected from the machine, leaving sufficient wire projecting beyond the gripping device for the formation of a head on the next nail.

The machine of the present invention differs from prior machines of the above described type in several important respects which enable the machine to be operated at a higher speed of production than existing machines. Briefly stated, the novel features of the present machine reside in driving the reciprocating heading ram by means of a balanced flywheel and crank construction which enables the crank shaft to be driven at a high speed, in complete balance, in spite of the rapidity with which the ram forms the nail heads. The improved machine also pro vides a continuously rotating ejector for positively clearing the cut nails from the machine, with the ejector operating in perfect tirned relation with the heading ram.

Other improved features of the machine include a mechanism for operating the wire grippers by means of preloaded torsion members which cause the girppers to firmly hold the wire during the heading operation, with provision for unloading the gripper members only when the wire is being fed after the heading operation. The wire feeding device is also of improved construction which permits uniform feeding of the wire, to produce nails of predetermined length, irrespective of variations in the wire size.

The above and other advantageous features of the invention will hereinafter more fully appear from the following description, considered in connection with the accompanying drawings, in which,

Fig. 1 is a plan view of a nail-making machine embodying the present invention.

Fig. 2 is a view in side elevation of the machine shown in Fig. 1.

Fig. 3 is a plan view showing the essential elements of the machine, without the supporting frame, to better show the relation between the parts.

Fig. 4 is a fragmentaiy plan view, on an enlarged scale, showing details of the gripper and knife mechanisms.

Fig. 5 is a vertical sectional view along the line 55 of Fig. 4, looking in the direction of the arrows.

Fig. 6 is a vertical sectional view along the line 66 of Fig. 4, looking in the direction of the arrows.

Fig. 7 is a vertical sectional view along the line 7--7 of Fig. 4, looking in the direction of the arrows.

Fig. 8 is a longitudinal sectional view along the line 8-8 of Fig. 1, looking in the direction of the arrows and on an enlarged scale, showing the heading of a nail.

Fig. 9 is a longitudinal sectional view similar to Fig.

8, showing the feeding of the wire with a headed nail thereon.

Fig. 10 is a detail showingof the wire feeding mechanism on an enlarged scale.

Fig. 11 is a diagram illustrating the operating cycle of the machine.

Figs. 12 and 13 are diagrams illustrating the operation of the wire feeding mechanism shown in Fig. 10.

Fig. 14 is a fragmentary sectional view along the line 14-14 of Fig. 10, looking in the direction of the arrows.

Referring first to Figs. 1 and 2, the working parts of the machine are mounted on a frame 1 of heavy construction, which frame is supported on a base 2, so that the wire W can enter the machine at a convenient height above the floor. The wire W is shown as entering the machine from the right, as viewed in Fig. 1, after passing through a number of straightening rolls 3 mounted on a bracket 4 extending from the frame 1.

The wire W is adapted to be intermittently fed into the machine by means of a reciprocating feeding device 5, which when moved to the left projects the wire W through a heavy anvil block 6 between a pair of grippers 7 movable at right angles to the travel of the wire. A pair of knives 8 are also movable at right angles to the line of wire feed and when closed, serve to cut 01f a completed nail which is then struck by an ejector 9 rotating in a space between the knives 8 and a heading ram 10, then in a retracted position, as shown in Fig. 4.

After a completed nail has been cut from the wire W by the knives 8, the protruding end of the wire is held between the grippers 7 and this protruding portion is swaged to form a nail head by the impact of the ram 16 which is backed up by the block 6 behind the grippers 7. The above described general operating cycle is then repeated upon opening of the grippers 7 to permit the feeding device 5 to again move the wire W an amount which determines the length of the completed nail that is cut by the next closing of the knives 8.

The above described elements of the machine are driven from a main shaft 11 supported in bearings 12 mounted in the frame 1, with one end of the shaft 11 being provided with a pulley 13 connected by a belt 14 to a suitable source of power such as an electric motor 15. As best shown in Figs. 3 and 8, the shaft 11 provides a crank 16 located between its bearings 12 at the middle of the machine, and in line with the movement of the wire W. The crank 16 carries a connectingrod 17, the outer end of which embraces a pin 18 mounted on a head 19 forming part of the ram 10. Therefore, rotation of the shaft 11 causes reciprocation of the ram 10 within a guide 20 provided by the frame 1, so that the end of the ram 10 will engage the protruding end of the wire held between the grippers 7 after each cut to swage a head thereon.

As previously pointed out, one of the objects of the present invention is to provide means for balancing the crank shaft which drives the heading ram, and for this purpose the shaft 11 carries a pair of flywheels 21 located on opposite sides of the crank 16, so that the entire mass of metal represented by the crank and flywheel is symmetrical with respect to the line of movement of the ram 10. Furthermore, the crank 16 is connected to a pair of balancing weights, shown for purposes of illustration, as cylindrical sleeves 22 freely movable in cylinders 2'3 projecting radially from the frame 1, with the axes of the cylinders 23 being displaced by an angle of degrees from each other, and from the axis of the ram 10. The sleeves 22 provide connecting rods 24, the outer ends of which are joined by pins 25 to the cap 26 of the ram connecting rod 17. Therefore, rotation of the crank 16 about the axis of the shaft: 11 to cause reciprocation of the ram 10 will be accompanied by guided movement of weights, as represented by movement 3 of the sleeves 22 in the cylinders 23, so as to obtain a balancing effect, in association with the counterweights 21a on the flywheels 21.

The practical effect of the balanced system of moving parts shown in Fig. 8 is to prevent transmission of any sustained inertia forces to the frame of the machine, via the main crank shaft bearings, thereby substantially eliminating vibration. The effect of the counterweighed flywheels 21 being located closely adjacent to the crank 16 is to avoid torsional stresses and possible fatigue failure of the crankshaft. Thus the machine can be run at extremely high speeds to obtain maximum rates of nail production, heretofore unobtainable with ram type machines of conventional construction. It is also to be noted that the guide 20 in which the ram moves provides ample bearings a for both the ram and its head 19, thereby reducing wear to a minimum.

Referring again to Fig. 3, there the mechanism for driving the other moving parts of the machine is shown, with the frame 1 being removed to better illustrate the relation between these parts. In this arrangement, countershafts 27 extend along opposites of the frame, at equal distances from the central crank 16, with the shafts 27 being driven in unison, although in opposite directions through gearing 28. The shafts 27 are supported in suitable bearings 29 provided by the frame 1 and each shaft 27 provides a crank 30, with counterweights 30a opposite to each crank 34?. As best shown in Fig. 5, each crank 30 is surrounded by one end of a connecting rod 31, the other end of which is connected by a pin 32 to a slide 33 movable between spaced horizontal guide ways 34 provided by the frame 1. A knife 8 is mounted on each slide 33, so that rotation of the shafts 27 will cause the knives 8 to move back and forth with the slides 33 to cause cutting of the wire W each time that the knives come together during one complete revolution of the main shaft 11, with all parts being in dynamic balance.

Each knife 8 is mounted within an opening .35 provided in a slide 33, and the inner end of the knife provides a beveled surface 36 which is in engagement with the inclined surface of a wedge block 37 that serves to back up the knife. The block 37 is adjustable within the opening 35 in a direction at right angles to the line of movement of the knife 8 by means of a screw 38, so that the knife can be accurately positioned within the slide 33. Following an adjustment of the knife 8 by means of the block 37, the knife is secured against movement within the opening 35 by means of a clamping plate 39 and cap screws 40. v

The knives '8 are so set by means of the above described adjusting means that when the two cranks 30 occupy the dead center positions opposite to the positions shown in Fig. 5, the knives will be closed and there-by cut the wire W while at the same time forming a point on the previously headed nail. The knives 8 are so set that they do not quite touch each other, although the wife will be cut through sufficiently to either completely separate the nail from the end of the wire, or hold it so lightly that the nail will be cleared when it is struck by the rotating ejector 9 which operates in the clear space between the knives 8 and the retracted ram 14 It will be evident from a consideration of Fig. 4that the knives 8 are spaced from the grippers 7 a distance such that a short length of Wire W will protrude beyond the grippers after each operation of the knives to sever a completed nail from the wire, which protruding portion provides sufficient metal for the formation of a head on the next nail, as will be later described.

In order to prevent the knives 8 from forcibly striking each other at the moment of cutting, the inward movement of each slide 33 is positively limited by a stop 41 in the form of a bar rigidly secured to the frame 1. As best shown in the broken away portion at the right of Fig. 4, the stop 41 extends into a slot 42 provided in the slide 33 with the outer end of the stop being secured to the frame by screws 43. The end of the slot 42 opposite to the stop 41 is of semicylindrical form so as to receive a shoe 44 of hardened metal, see Fig. 5, which engages the stop 41 when the slide 33 is moved to the right-hand end of its stroke which causes cutting of the wire by the knives 8. The fact that the stops 41 thus positively limit inward movement of the slides 33, permits the knives 8 to be set very closely so as to cleanly sever the wire and form a point on a nail, without any possibility of the cutting edges of the knives forcibly coming into contact with each other. I

As previously pointed out, the ejector 9 is adapted to rotate within the space between the knives 8 and the retracted ram 10, and as best shown in Fig. 4 the ejector 9 is mounted on a shaft 45 extending parallel to the countershafts 27. The ejector 9 is in the form of an arm, the outer end of which is adapted to travel in a circular path which in the dotted line position of Fig. 3 intersects the line of movement of a completed nail when it is moved beyond the knives 8 after the heading operation. The ejector 9 is adjustable on the shaft 45 by means of a sleeve 46 which is keyed to the shaft 45, with the sleeve 46 providing a sliding keyway 46a. With this mounting the sleeve 46 can be locked in position on the shaft 45 by means of a set screw 47, thereby permitting the ejector 9 to be adjusted longitudinally of the shaft 45, so that it will strike a nail that has been cut from the wire at any desired point in its length.

The inner end of the shaft 45 carries a sprocket 48 which is connected by a chain 49 to a sprocket 50 mounted on a stud 51 supported by a lug 51a projecting from the frame between the

shafts

27 and 45. The stud 51 carries a second sprocket 52 connected by a chain 53 to a sprocket 54 on the shaft 27. Since the two pairs of sprockets 4-8, 56 and 52, 54 are of the same relative diameters, the ejector shaft 45 will be driven at the same speed as the main shaft ll, and the ejector 9 will move through the space between the knives 8 and the retracted ram once during each complete revolution of the main shaft 11.

As previously stated, the grippers 7 are movable at right angles to the line of wire feed within a block 6 and the mechanism for operating the grippers so as to tightly hold the wire during the head forming operation is best shown in Figs. 4, 6 and 9. Each gripper '7 is of dovetail cross section and is slidable within a guide plate '55 mounted within a slot 56 extending across the front of the block 6. The inner end of each gripper provides a groove 57 which is adapted to fit one-half of the wire W when the grippers are closed and each grove 57 provides number of transverse ribs 58 that are adapted to form the usual burrs on opposite sides of the wire adjacent to the head that is to be formed on each nail. Fig. 6 shows the grippers 7 in closed position upon the wire W, which is the positionoccupied by the grippers during approximately one-half of each complete revolution of the main shaft 11, following the feeding of the wire. In other words, the function of the grippers 7 is to firmly hold the Wire during the formation of a head on the protruding wire end, as well as during the operation of the knives, so that the only time that the grippers do not hold the wire is during the feeding thereof. Therefore, in the following description of the gripper mechanism, the means for holding the grippers closed will be considered first, with particular reference to the arrangement for controlling the preloaded torsion rod arrangement which holds the grippers normally closed under heavy pressure.

Referring now to Figs. 4 and 6, the outer end of each gripper provides a seat 59 for receiving one end of a thrust bar 60, the other end of which isreceiv'e'd in a seat 61 provided on the head 62 of a lever 63 which extends from the head in a direction substantially parallel to the shaft 27. The head 62 extends above and below the lever 63 and is rotatably supported in bearings 64 received within a cylindrical opening 65 providei in the frame 1. This opening 65 is closed by a cap 66 which serves to hold the parts of the bearings 64 in position, with the two caps 66 appearing as circles in Fig. 1. Each head 62 is therefore rotatable about a vertical axis extending at right angles to the line of movement of a gripper 7, so that turning of a lever 63 about this axis will impart inward movement to the gripper through the thrust bar 60.

Each head 62 provides a central opening 67 for receiving the upper end of a torsion rod 68 which extends downwardly through the frame 1 into the base 2, as indicated in dotted lines in Fig. 2. The lower end of each rod 68 is received in a second head 69 that is turnable within a bearing 70 mounted in the base 2 and the rod 68 is secured to the

heads

62 and 69 respectively, by means of splines or ribs 71 cut in the ends of the rod which fit into serrations 72 in each head to provide a rigid connection at each end of the rod.

As best shown in Fig. 6, the heads 69 at the lower ends of the torsion rods 68 are provided with arms 73 extending towards each other and overlapping at their ends along the center line of the machine. Each arm provides a slot 74 for receiving a pin 75 which also passes through the sides of a fork 76 formed on the end of a pull rod 77, see Fig. 2. The rod 77 passes through a web 78 provided by the base 2, and a nut 79 threaded on the rod 77 serves to draw the rod 77 towards the lugs 78 and thereby turn both arms 73, about the vertical axes of the associated torsion rods 68. Therefore, by turning the nut 79 it is possible to set up a torsion in the rods 68 which will serve to maintain the grippers 7 in engagement with the wire under a pressure which is determined by the amount of torsion in the rods 68 for a particular setting of the nut 79.

When assembling the parts of the gripper mechanism, the grippers 7 are mounted in the guide plate 55 with their inner ends in engagement and with the heads 62 maintaining the thrust bars 60 against the outer ends of the grippers. In this position, the arms 73 of the lower heads 69 are in substantially parallel relation, since the rods 68 have not at that time been placed under torsion. However, it will be apparent from a consideration of Fig. 3 that turning of the nut 79 will cause the pull rod 77 to turn both arms 73 on the lower heads 69, and that such movement will cause the upper heads 62 to urge the grip pers 7 together with a strong pressure. Obviously, a very small amount of movement imparted to the heads 69 will serve to twist the torsion rods 68, since the upper heads 62 are then incapable of turning movement due to the engagement of the grippers with the wire.

It is therefore possible to very closely determine the pressure that will be exerted on the wire W by the grippers 7 by turning of nut 79; for example, when rods 68 having a diameter of .770" and a length of 28", are twisted by heads 69 through an angle of approximately 30 with respect to the upper heads 62, the resulting torsion in the rods 68 will hold the grippers 7 closed with a pressure of approximately 5000 pounds.

As previously pointed out, the grippers 7 firmly hold the wire W while a head is being formed on the protruding end of the wire by the ram 10. When the ram strikes the wire and forms the head with a swaging action, the grippers 7 are backed up to receive the impact of the ram 18 by the heavy block 6 in which the grippers are held by the plate 5.6. The thickness of the head that is formed on the wire is determined by the position of the front face of the block 6 with respect to the ram 10, and the construction is such as to permit ready adjustment of this thickness.

For this purpose, the frame 1 provides an abutment 89 to which the block 6 is secured by means of a stud 81 extending through an opening 82 in the abutment, the center of which coincides with the line of the wire feed, it being noted that the stud 81 provides a wire passage 81a, see Fig. 9. Che end of the stud 81 provides a vertically extending gib 83 which is received in a dovetail slot 84 provided in the rear face of the block 6, as best shown in Fig. 4. A nut 85 on the stud 81 serves to draw the gib and the block toward the abutment and the exact position of the front face of the block 6 with respect to the ram 18 is determined by a gauge plate 86 located between the abutment 80 and the rear face of the block 6. The thickness of this plate 86 will therefore determine the length of stock that is available to form a nail head on the end of the wire W. Should it be desired to change this length, the plate 86 can be readily removed by loosening the nut and substituting another plate of slightly ditferent thickness.

As previously noted, the preloaded torsion rods 68 maintain the grippers 7 in close engagement with the wire W during heading operation by the ram 10 and the cutting off of a nail by the knives 8. During the interval between the heading and cutting operations, it is necessary to feed the wire between the grippers 7 into the space between the knives 8 and the then retracted ram, and there will next be described the mechanism for separating the grippers 7 a sufficient amount to permit the wire feed.

When the grippers 7 are closed, the levers 63 on the heads 62 extend substantially parallel tothe shafts 27, in which position the end of each lever serves to support a stud 87 in substantially horizontal plane. As best shown in Fig. 7, one end of the stud 87 extends toward the adjacent shaft 27 and is rounded so as to be freely received in a socket 88 formed on the end of a thrust. bar 89. This bar 89 extends through an opening 90 provided in a vertical web 91 forming part of the frame 1 and its inner end is seated in a piston 92 movable in a cylindrical bore 93 provided at the lower end of a lever 94. The lever is mounted on a pivot pin 95 extending parallel to the shaft 27 and its lower end carries a roll 96 that is normally in engagement with the surface of a cam 97 on the shaft 27.

The cam 97 provides a projection 98 on the surface thereof, which, when engaged with the roll 96 is adapted to turn the lever 94 in a counterclockwise direction, as viewed in Fig. 7 and thereby exert a force on the thrust bar 89 which is transmitted to the stud 817 at the end of the lever 63. It will be evident from a consideration of Fig. 4 that when the left-hand lever 63 is turned in a clockwise direction through the operation of the cam 97 and thrust bar 89, the head 62 of the lever will move the seat 61 for the thrust bar 60 away from the gripper '7. It is to he noted that this turning movement of the head 62 is in a direction opposite to that in which the head tends to be turned by the preloaded torsion rod 68, so as to release the continuous force with which the gripper 7 is held against the wire W.

The degree of turning of the upper heads 62 by the levers 63 necessary to release the grippers 7 from the wire W, is very small compared to the torsional preloading of the rods 68 by the lower heads 69 and is only sutiicient to release the pressure of the grippers 7 for a predetermined period determined by the angular displacement of the cam projection 98. For example, assuming that the torsion rods 68 have been adjusted to obtain a preload windup of approximately 30 by turning the lower heads 69 through that angle, with the grippers 7 in contact with the wire, the turning of the upper heads 62 by the levers 63 through an angle of approximately 2 will be sufficient to release the grippers 7 to the point where they will permit feeding of wire W between the grippers by the device 5.

in order to obtain separation of the grippers 7 from the wire W following their release, and in advance of feeding the wire, the grippers 7 are adapted to be moved away from each other by a pair of arms 99 mounted on pivot pins 100 extending vertically through the anvil block 6. The end of each arm 99 is received in an opening 101 provided in a gripper 7 and each arm 99 is urged outwardly with respect to the block 6 by a spring 102.

The inner end of each spring 102 is received in a seat 103sprovided by the block 6, with the spring engaging one side of a plate 104, the opposite side of which provides a seat 104a for the end of a set screw 18:": threaded in arm 99. The screw 1% is locked by means of a nut 105a, so that the pressure exerted by the spring to turn its arm 99 about the pivot 1191) can be adjusted.

Under normal operating conditions, the preload windup of the torsion rods 68 is such as to hold the grippers 7 closed upon the wire W with a heavy pressure in the order of 5060 pounds, as previously pointed out. However, in order to cause separation of the previously released grippers 7, in advance of the wire feed, it is sufficient to adjust the springs 192 so that they are preloaded to exert a force of approximately 200 pounds on each arm 99. It has been found that the relative force exerted by each spring 1 12 is quite sufficient to move the associated gripper outwardly to clear the wire W, because of the fact that turning the upper heads 62 through an angle of only 2 will unload the thrust bars 69 sufliciently to permit the grippers 7 to separate far enough to insure clearance of the ribs on the ends of the grippers from the barbs that have been formed on the wire by pressure of the ribs 58. This unloading of the thrust bars 60 occurs only when the horizontal levers 63 are turned by the thrust bars 8%, and the operating mechanism for the vertical levers 94 is so arranged that there is no play between the various parts when the cams 97 impart movement to the levers 94 to unload the thrust bar 60 prior to separation of the grippers.

The above noted arrangement for preventing play between the parts of the gripper releasing mechanism is best shown in Fig. 7 and consists of means for maintaining fluid under pressure between the piston 92 for the thrust bar 89 and the cylindrical bore 93 at the iower end of the lever 94. For this purpose, the pivot pin 95 for the lever 9 provides a passage 1% which is connected to a source of fluid under pressure, such as the pump P for supplying oil to the bearings of the machine, see Fig. l. The passage 1% is in continuous communication with a passage 1117 extending through the lever 94 by means of a circular groove 1% surrounding the pivot pin 95. The passage 1117 in the lever 94 is in communication with the bore 93, with the flow of oil between the bore and the passage being under the control of a check valve 1&9 in the form of a ball that is held seated by a spring 110.

With the above described arrangement, oil under pressure from the passage 1% normally opens the valve 199 sufiiciently to maintain oil between the piston 92 and the end of the bore 93. Since the outer end of the lever 63 remains in a fixed position when the grippers 7 are held closed by preloading of the torsion rods 63, the oil pressure has the effect of talking up any play between the thrust bar 39 and the lever 94, when the roll 96 is hearing on the non-operating surface of the cam 97. Therefore, when the cam projection 9?: engages the roll 96 so as to impart turning movement to the lever 94, the oil between the piston 92 and the bottom of the bore 93 acts to transmit this motion to the head lever 63, without play. Consequently, as the lever 94 is moved by the cam projection 93, the ball valve 109 closes to trap the oil. The net result of the functioning of the parts described above is to maintain all parts of the gripper operating mechanism under compression at all times, so that the grippers 7 either engage the wire W under heavy pressure, or are released to permit feeding of the Wire without any lost motion which would ultimately result in wear and the parts getting out of adjustment.

As previously pointed out, the wire W is adapted to be intermittently fed into the machine by means of a reciprocating feeding device 5, the construction of which is best shown in Figs. 9 and 10. The feeding device 5 consists of a carriage 111 that is supported for horizontalmovement on a guide 112 extending between lugs 113 provided by the frame 1. The carriage 111 is adapted to be moved back and forth by means of a connecting rod 114, the ends of which are mounted on pins 115 and 116provided by a crank disc 117 and the carriage 111, respectively. The crank disc 117 is mounted on the end of a shaft 118 which as shown in Fig. 3, is connected by gearing 119 to a countershaft 27.

Therefore, rotation of the shaft 118 will impart recip rocating movement to the carriage 111, and this movement utilized to operate a wire feeding device, the details of which are shown on an enlarged scale in Fig. 10. The upper end of the carriage 111 serves to support a feeding head 120 which extends upwardly through a slot 121 provided in the top of the frame 1, and extending parallel to the upper guide 112a on which the carriage moves. The head 1213 provides an opening 122 through which extends a stud 123, with the stud providing a slot 124 through which the wire W passes freely. The stud 123 extends above the head 120 and serves to receive a pair of shoes 125 that are in the form of flat washers composed of wear resistant material, between which the wire passes.

The shoes 125 provide grooves 126 for receiving the wire W, see Fig. 14, and the shoes are yieldingly held in engagement with opposite sides of the wire by means of a spring 127 surrounding the stud 123. The upper end of the spring 127 is seated in an opening 128 provided in the head 120, while the lower end of the spring bears on the top of a flange 12% secured to the lower end of the stud 123. Therefore, the spring 127 normally exerts a downward pull on the stud 123 which is transmitted to the shoes 125 through a nut 130 on the stud to cause the Wire VJ to be closely engaged by the shoes 125. The pressure exerted on the wire by the shoes 125 can be adjusted by means of the nut 130 which is threaded on the upper end of the stud 123. The location of the nut 13 3 determines the position occupied by the lower end of the stud 123, and with the stud free of any force opposing the downward pressure exerted by the spring, the spring loading is such as to cause the shoes 125 to exert a pressure of 300 pounds on the wire W while the carriage 111 is traveling through its feeding stroke, which is to the left, as viewed in Fig. 9.

Fig. 9 shows the position occupied by the carriage 111 at the end of the wire feeding stroke wherein the head 120 is near the left-hand end of the slot 121. At this moment, a nail N with a head formed thereon has been fed beyond the grippers 7 in readiness to be severed from the wire by closure of the knives 8. It is to be noted that in this position, the crank pin 115 is substantially on left dead center, and that the lower end of the stud 123 is just being engaged by a cam projection 131 formed on the surface of a sleeve 132 which forms part of the outer end of the connecting rod 114. Therefore, when the carriage 111 starts its return movement to the right by turning of the crank 117 in a clockwise direction, turning of the sleeve 132 about the pin 116 in a counterclockwise direction will cause the cam projection 131 to force the stud 123 upwardly, as indicated by the arrow in Fig. 12, and thereby compress the spring 127 sufficiently to release the pressure of the shoes 125 on the wire.

The cam projection 131 will continue to engage the stud 123, as the crank disc 137 completes one half of a revolution, so that movement of the feeding head 120 in the slot 121, in preparation for another feed of the wire, will take place without any appreciable drag by the shoes 125 on the wire, which at that time is firmly held between the grippers 7. However, as soon as the crank pin 115 passes beyond right dead center and starts movement of the carriage 111 to the left, clockwise turning of the sleeve 132, as shown in Fig. 13, will disengage the cam projection 131 from the stud 123, so that the Spring 127 will again exert a downward pull on the stud 123 to cause the wire W to be engaged by the shoes 125 with a force suflicient to feed the wire between the grippers 7 which have previously been released through turning of the levers 63 by the earns 97.

As a result of the functioning of the above described feeding mechanism, each complete revolution of the shaft 118 will cause a predetermined length of wire to be fed, after which the carriage 111 will be retracted to position the head 120 for the next feed. The length of wire that is fed by each movement of the carriage 111 is determined by the displacement of the crank pin 115 on the disc 117 with respect to the axis of the shaft 118, and the position of the pin 115 is made adjustable in order to vary the length of the wire feed which directly determines the length of the nails N produced by the machine.

For this purpose, the pin 115 is mounted on a block 133 that is movable between ways 134 provided by the crank disc 117. An adjusting screw 135 is threaded into the block 133, with the screw 135 being held against axial movement by a bar 136 extending between the ways 134. By turning the screw 135, the block 133 can be moved between the ways 134 in either direction so as to vary the distance between the pin 115 and the axis of the shaft 118.

In order to balance the shaft 118, the crank disc 117 provides a counterweight 137 on the opposite side of the shaft axis from the pin 115. This counterweight 137 is also adjustable on the ways 134 by means of the screw 135 which is threaded into the counterweight. The threads on the screw 135 are such that turning thereof will cause the block 133 and the counterweight 137 to be moved in opposite directions. In this way, movement of the pin 115 toward or away from the shaft 118 will result in moving the counterweight 137 a corresponding distance, thereby keeping the shaft in balance for any given setting of the crank pin 115.

By reason of the above described cooperation between the end of the stud 123 and the cam projection 131, it is obvious that the shoes 125 will either engage or release the wire in accordance with the direction of movement of the carriage 111 by the connecting rod 114. In other words, the duration of the engagement of the cam projection 131 with the stud 123 is determined entirely by the degree of turning movement of the connecting rod 114 on its pin 116, so that any adjustment in the length of the feed will in no way alter the timing of the gripping and releasing action. Furthermore, any variations in the diameter of the wire being handled, within customary tolerances, does not appreciably aifect operation of the feeding device, because the shoes 125 either engage the wire with the full loading of the spring 127, or release the wire when the stud 123 is positively relieved from the pressure of the spring 127 by engagement with the cam projection 131.

Having described the various parts entering into the machine, the operating cycle thereof will next be described with reference to the diagram of Fig. 11. This diagram represents the various operations that are performed by the elements of the machine during one complete revolution of the main shaft 11, with the cycle starting at when the crank 16 is on right dead center and the ram 10 has formed a head on a nail, as shown in Fig. 8. At that moment the grippers 7 are tightly holding the wire, with the short length of wire projecting beyond the grippers providing sufiicient metal for forming the head. At that time also, the feed carriage 111 is still moving to the right, with the shoes 125 sliding freely on the wire, although the crank pin 115 is almost on right dead center.

As the main shaft 11 turns through an angle of 18 from dead center, the grippers 7 start to separate due to the operation of the levers 94 by the earns 97, by which time the ram 10 has started its return movement away it? from the grippers. Shortly thereafter, at 27, the wire feed carriage 111 reaches right dead center, so that the wire feed starts immediately with the grippers 7 being fully open at 36.

At 59, the knives 8 are fully open, with the wire feed continuing to move the nail N with a head thereon into the open space between the gripper block 6 and the ram guide 20, as shown in Fig. 9. The feed continues as the ram 10 is fully retracted at 180, with the ram starting back as the wire feed carriage 111 reaches the end of its feeding stroke 207 as the crank pin 115 reaches left dead center. By this time the knives 8 have moved inwardly to the point where they touch the wire at 209, with the grippers also having reengaged the wire at this point.

At 239 the knives 8 come together fully to sever the finished nail from the wire, and at 241 the ejector 9 strikes the nail and it falls downwardly into a suitable container provided in the base 2. At 270 the knives have been partially retracted, so as to be out of the way of the inwardly moving ram which has then reached a point about half way in its travel toward the grippers, with the knives being further retracted as the ram approches the protruding wire end.

At 351, the projections 98 on the cams 97 engage the rolls 96 on the levers 94 thereby starting the action previously described with reference to Fig. 7, although due to elastic deflections in the members, the grippers 7 do not start to move apart until approximately 18 past dead center. Therefore, when ram 10 again hits the wire W to form a head at 360, the grippers 7 still hold the wire tightly as the cycle is completed.

We claim:

1. In a nail-making machine comprising :a drive shaft, wire feeding means, wire gripping means, wire cutting means and a reciprocatory ram for swaging the wire to form a nail head, all driven in timed relation from said shaft to produce a complete nail for each revolution thereof, the combination therewith of a rotatable ejector element and means for driving said element from said shaft to cause it to travel in a circular path across the line of wire feed, after the operation of said wire feeding and cutting means, and before the return of said ram for the formation of a nail head.

2. In a nail-making machine comprising a drive shaft, wire feeding means, wire gripping means, wire cutting means and a reciprocatory ram for swaging the wire to form a nail head, all driven in timed relation from said shaft to produce a complete nail for each revolution thereof, the combination therewith of a rotatable ejector element and means for driving said element from said shaft to cause it to travel in a circular path across the line of wire feed, so as to strike a nail after it has been cut from the wire and while said ram is separated from said wire gripping means, by at least the length of a complete nail.

3. In a nail-making machine comprising a drive shaft, wire feeding means, wire gripping means, wire cutting means and a reciprocatory ram for swaging the wire to form a nail head, all driven in timed relation from said shaft to produce a complete nail for each revolution thereof, the combination therewith of a rotatable shaft extending parallel to the line of wire feed, an ejector arm extending from said shaft and movable in a circular path intersecting the line of wire feed and means for driving said ejector shaft from said drive shaft to cause said arm to strike a nail after the operation of said cutting means and while said ram is separated from said wire gripping means by at least the length of a complete nail.

4. In a nail-making machine comprising a drive shaft, wire feeding means and a reciprocatory ram driven from said shaft for swaging the wire to form :a nail head thereon, the combination therewith of a gripper movable transversely to the wire, preloaded torsion spring means acting on said gripper to cause it to engage the wire under pressure, and means driven by said drive shaft and operating in timed relation with said drive shaft for releasing said gripper from the action of said spring means to permit said gripper to disengage the wire during the operationof said wire feeding means.

5. In a nail-making machine comprising a drive shaft, wire feeding means and a reciprocatory ram driven from said shaft for swaging the wire to form a nail head thereon, the combination therewith of a pair of grippers movable transversely to the wire, preloaded spring means acting on said grippers to cause them under pressure, means operated by said drive shaft and operating in timed relation with said drive shaft for releasing said grippers from the action of said spring means, and other spring means, of lesser magnitude than said first named spring means, for sepair g said gri pers upon operation of said releasing means.

In a nail-making machine comprising a drive shaft, wire feeding means and a reciprocatory ram driven from said shaft for swaging the wire to form a nail head thereon, the combination therewith of a gripper movable transversely to said wire, a preloaded torsion rod connected to said gripper for exerting pressure on the Wire, and means operated by said drive shaft and operating in timed relation with said drive shaft for releasing said gripper from the pressure of said torsion rod to permit the passage of wire past said gripper during the operation of said feeding means.

7. In a nail-making machine comprising a drive shaft, wire feeding means and a reciprocatory ram driven from said shaft for swaging the wire to form a nail head thereon, the combination therewith of a pair of grippers-movable transversely to said wire, a pair of preloaded torsion rods connected to said grippers for holding said grippers together to exert pressure on the wire, 'means operated by said drive shaft and operating in timed relation with said drive shaft for releasing said grippers from the pressure of said torsion rods, and means for separating said grippers upon operation of said releasing means.

8. A nail-making machine comprising in combination a drive shaft, a reciprocatory heading ram driven from said shaft by a crank thereon, a countershaft connected to said drive shaft and extending parallel to the line of movement of said ram, 21 reciprocatory slide driven in unison with said drive shaft by a crank and carrying a wire feeding device movable toward and away from said ram, grippers driven from said countershaft to hold the wire while a head is formed thereon byrsaid ram, cutters driven from said countershaft to sever the wire after a head has been formed thereon and the wire has been advanced by the feeding device on said second slide, and a rotatably mounted ejector driven by said drive shaft for travel in a circular path intersecting the line of wire feed.

9. in a nail-making machine, a wire gripping mechanism comprising in combination a stationary block providing an opening for the passage of wire, a gripper slidable in said block at right angles to said wire, a head turnable about a fixed axis for imparting movement to said gripper, a twistable member extending along the pivotal axis of said head and connected at one end to said head, and means for imparting a turning movement to the other end of said member to place it under torsion and cause said head to hold said gripper in engagement with the wire.

10. in a nail-making machine, a wire gripping mechanism comprising in combination a stationary block providing an opening for the passage of wire, a gripper slidable in said block at right angles to said wire, a head turnable about a fixed axis for imparting movement to said gripper, a twistable member extending along the pivotal axis of said head and connected at one end to said head, means for imparting a turning movement to the other end of said member to place it under torsion 12 and cause said head to hold said gripper in engagement with the wire, and means acting on said head for turning it in a direction opposite to that in which it is urged by the torsion in said member for releasing the pressure normally exerted by said gripper on the wire by the torsional preloading of said member.

11. In a nail-making machine, a wire gripping mechanism comprising in combination a stationary block providing an opening for the passage of Wire, a gripper slidable in said block at right angles to said wire, a head turn -le about a fixed axis for imparting movement to said gripper, a twistable member extending along the pivotal axis of said head and connected at one end to said head, means for imparting a turning movement to the other end of said member to place it under torsion and cause said head to hold said gripper in engagement with the wire, means acting on said head for turning it in a direction opposite to that in which it is urged by the torsional preloading of said member, and means acting on the gripper for moving it away from said wire an amount determined by the degree of turning of said head in opposition to its turning by said torsion member.

12. In a nail-making machine, a wire gripping mechanism comprising in combination a stationary block providing an opening for the passage of wire, a gripper slidable in said block at right angles to said wire, a head turnable about a fixed axis for imparting movement to said gripper, a rod extending along the pivotal axis of said head and connected at one end to said head, means for imparting a turning movement to the other end of said rod to place it under torsion and cause said head to hold said gripper in engagement with the wire, an arm extending from said head, a pivotally mounted lever connected to the end of said arm by a thrust member, and means for operating said lever to transmit turning movement to said arm through said thrust member while always maintaining the motion transmitting parts of said mechanism under compression, .as the turning of said head by said lever releases the pressure exerted by said torsion rod on said gripper.

13, In a nail-making machine, a wire gripping mechanism comprising in combination a stationary block providing an opening for the passage of wire, a gripper slidable in said block at right angles to said wire, a head turnable about a fixed axis for imparting movement to said gripper, a rod extending along the pivotal axis of said head and connected at one end to said head, means for imparting a turning movement to the other end of said rod to place it under torsion and cause said head to hold said gripper in engagement with the wire, an arm extending from said head, a pivotally mounted lever connected to the end of said arm by a thrust member, means for operating said lever to transmit turning movement to said arm through said thrust member, and thereby release the pressure exerted by said torsion rod on said gripper by turning said head and means for maintaining fluid under pressure between the motion transmitting parts of said mechanism to prevent any lost motion between such parts.

References Cited in the file of this patent UNITED STATES PATENTS 458,391 Glover Aug. 25, 1891 644,603 Hutchins Mar. 6, 1900 1,427,845 Priesthoff Sept. 5, 1922 1,813,276 Burtnett July 7, 1931 2,235,160 Ljungstrom Mar. 18, 1941 2,315,108 Chism Mar. 30, 1943 2,406,808 Connor Sept. 3, 1946 2,495,885 Blume Jan. 31, 1950 2,503,029 Conner Apr. 4, 1950 2,580,055 Weber Dec. 25, 1951 FOREIGN PATENTS