US2290440A - Riveting machine - Google Patents

Description

July 21 1942. w. R. LlNDsfrRoM f 2,290,440

` RIVETING MAGHINE Filed May 1, 1959 2 Sheets-Sheet 1 July 21,1942. w. R. LINDSTOM 2,290,440

A RIVETING YMACHINE Filed May l, 1939 2` Sheets-Sheet 2 WW ff. m4/55.

Patented July 21, 1942 UNITED STATES PATENT OFFICE Y 2,290,440 RIVETING MACHINE Walter R. Lindstrom, Minneapolis, Minn. Application May 1, 1939, serial No. 270,97'i

Claims.l (Cl. 78-49) This invention relates to riveting machines and more particularly to machines for riveting relatively light materials as distinguished from apparatus for riveting structural steel and similar extremely heavy materials.

Riveting machines are used in many manufacturing .plants for connecting sheet metal and similar plates or levers and it is the common practice in general industry to utilize pre-formed rivets which are made with a head formed on one end. 'Ihese rivets are placed in a hopper on the riveting machine and means is provided for sorting the rivets and feeding them in proper position for insertion through apertures in the materials to be riveted. Not only is rather eX- pensive sorting and feeding mechanism needed, but the cost of the rivets themselves is comparatively high.

It is a `general object of my invention to provide a riveting machine which utilizes a supply of rivet stock inthe form of a long strand which is fed into the machine, cut into desired lengths for individual rivets and then fed to the materials to be riveted. After the cut lengths of rivet stock are fed to the work, heads are for-med on the ends of the cut lengths of stock tightly securing the riveted parts.

Another object of the invention is to provide means for adjustably and synchronously feeding and cutting the elongated strand of rivet stock in relation to the operation of the head forming dies.

Another object of the invention is to provide improved means for locking the work to .be riveted with respect to the feeding means and dies.

Another object of the invention is to provide means for stopping the feed of rivet stock when the end of the strand of stock is approached.

A still further object ofthe invention is to provide improved die assembly for riveting machines.

Another object of the invention is to provide an improved method for forming and heading rivets.

These and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and, in which:

Fig. 1 is a side elevation of a riveting machine embodying my invention with a portion of the main frame broken away;

Fig. 2 is an enlarged view generally similar to Fig. l with portions of the main frame broken away and other parts of the machine in vertical section;

Fig. 3 is a horizontal section taken approximately on the line 3-3 of Fig. 2;

Fig. 4 is a vertical section taken approximately on the line 4-4 of Fig. 2;

Fig. 5 is a .vertical section taken approximately on the line 5 5 of Fig. 2; and

Fig. 6 is an enlarged vertical sectional View through the lower die head.

In the embodiment of my invention shown in the drawings there is provided a main frame which includes an upright post 'I and an angularly disposed arm 8 which has an enlarged outer end, as shown in Figs. 1 `and 2. A bracket 9 extends upwardly from the top of the vertical post 'I and pivotally supports a rocker arm I0 preferably at the longitudinal center of the arm. The left-hand end of the arm is connected by a suitable pivot II to a reciprocating shaft I2 which is connected to a suitable source of power. The pivot II is mounted in a slot I3 in the rocker arm I IJ to vary the throw of said rocker arm.

A horizontally disposed tubular guide I4 extends through the vertical post 'I and this guide is adapted to receive a strand I5 of rivet stock. 'I'he rivet stock may be in the form of a wire supplied from a relatively large roll on a suitable rotatable reel not shown. The strand of rivet stock I5 is run between a pair of feed rollers I6 and IT, the upper feed roll I6 being knurled as shown in Figs. 3 and 4, and the lower roll I1 being provided wth a circumferential groove I8. The upper feed roll IE is carried by |a shaft I9 and, as best shown in Fig. 4, the roll I6 is mounted in a slot in the frame casting 8. The roller I6 is mounted for rotation with the shaft I9 and said shaft extends outwardly from one side of the casting 8 and carries a sleeve 2B which has a 'pair of ratchet gears 2| and 22 formed thereon. The extreme end of the shaft I9 carries a drum-like .cap 23 which is rotatable on said shaft and held .by a spring retaining ring 24. The element 23 has a pair of ratchet .pawls 25 mounted thereon and these pawls are adapted to engage the teeth on the gear 22 when the drum-like shell 23 is rotated in one direction. When turned in the opposite direction, the pawls 25 slip over the gear teethV in the manner of the usual ratchet end pawl. The shell 23 is connected by a lever 2S as shown in Figs. 1 and 2 to the right-hand end of the rocker arm III. The upper end of the lever 26 is connected to the arm in a slot 2'I to permit adjustment of the throw imparted by the rocker arm I8 through the lever to the rotatable shell 23. Movement of the rocker arm imparts an oscillatory motion to the shell 23 and through the medium of the ratchet gear 23 and pawls 25 imparts movement to the shaft I9 and knurled wire feed roll I6. This progresses the strand of rivet stock I in a step by step manner. The lower feed roll I1 is mounted on a shaft I1a, and said shaft is vertically slidable on pins 28 which are threadedly secured in the main casting 8. As shown in Fig. 4, the lower ends of the pins are lbridged by `a strap 29 which is slidable on the pins and compression springs 38 are interposed .between the strap 29 and the roller shaft I1a on the pins 28. Slots 3I in the `casting 8 permit vertical movement of the shaft I1a and its roller I1. An angular arm 32 is pivotally secured to the lower portion of the casting 8 on a pin 33. The opposite end of the arm 32 is bifurcated and carries a -grooved roller 34 as best shown in Figs. 2 and 5. The wire stock I5 is threaded between the bifurcated ends of the arm 32 beneath the roller so that the roller rides on the rivet stock in the manner of .a trolley. A screw 35 is threaded through the arm 32 and bears against the under side of the bar 29, and the arm 32 is so formed that when its roller is riding upon the wire rivet stock it will press the :cross bar 29 and the springs 3B upwardly so that the rivet stock I5 .will be gripped between the feed rollers I6 and I1. However, when the end of the elongated strand of rivet stock ypasses the roller 34 on the arm 32, said arm will drop down relieving the spring pressure exerted on the roller I1, and the feeding of this shortened length olf rivet stock will be halted. This prevents small lengths of stock from `feeding into the casting where it will be extremely diiiicult to remove.

Stock which is fed through the feed rollers I6 and I1 passes through an aperture 36 in the main casting 8 and through an aligned aperture in a tool steel plate 31. As shown in Fig. 2, the wire feed mechanism has moved the forward end of the strand of rivet stock through the two aligned openings, and the extent of this movement is determined by the length of cut portions of rivet stock desired for the formation of a single rivet.

The casting 8 at its right-hand side as viewed in Figs. 1 through 3 is provided with a pair of spaced flanges 8a. These flanges are normally joined by a detachable plate 8b. In the space provided by the flanges v8a. and the plate 8b I position the stock cutter and the upper movable riveting die with their operating mechanism. A vertically disposed rack 38 is provided with a series of teeth 39 along its left-hand side, and said rack element is pivotally connected at its upper end to a link 40 which is in turn pivotally secured to the right-hand end of the rocker arm I8. The rack 38 telescopes vertically into a hollow die supporting body 4I. The rear or left-hand vertical wall of the body 4I is apertured at 42 and in this aperture is mounted a pinion 43. The teeth of this pinion mesh with the teeth on the rack 38 and also with a similar series of teeth 44 on the outer or right-hand face of the tool steel plate 31. The outer telescoping body 4I carries a tool steel insert 45 in vertical alignment with the above described opening in the plate 31 through which the end of the rivet stock protrudes. Therefore, Vertical downward movement of the outer telescoping element 4I causes the tool steel insert 45 to shear off the protruding end of the rivet stock I5.

The telescopically movable rack 38 has a die plunger 46 extending downwardly therefrom through an opening 41 in the outer telescoping element 4I. Downward movement of the rack 38 causes rotation of the pinion 43 and due to the meshing of said pinion with the rack on the xed plate 31, the hollow die head carrying element 4I will also move, but at only half the speed of the rack 38. It, therefore, and naturally, travels only half the distance of said rack.

The hollow die head carrier 4I supports the upper die head 48, and said die head is removably retained by means of a set screw 49. The die head 48 has an axial bore 50 therethrough to receive the die plunger 46 which reciprocates therein. The outer telescoping die carrier 4I has an open space or channel 5I which leads from the rivet stock cutter 45 downwardly and communicates with the axial bore 56 in the die element 48. Thus when a length of rivet stock or wire is cut ofi it drops down through the passageway 5I and enters the lower portion of the die bore 50. The lower` end of the die 48 is concave, as best shown in Fig. 2, and the lower end of the movable die plunger 46 moves downwardly only as far as the bottom of said concave portion. The die 48 is retained against complete removal from the telescoping element 4I which carries it through the medium of a removable block 52, as shown in Figs. l and 2. When the set screw 49 is loosened, the die can slip downwardly until the slanting face 48a contacts the corner 52a on the block 52. This exposes the lower portion of the bore 50 in the die, and permits cleaning should any particles of metal or other substances block the bore 50. Complete removal of the die is accomplished by detachment of the blocks 52 which may be secured by suitable screws.

The lower die is supported by a rigid holder 53, as shown in Figs. 2 and 6, and this die is made up of an outer sleeve 54, an inner sleeve 55 which is slidable in said outer sleeve, and a pilot pin 56 which is mounted axially within the inner sleeve 55. The outer sleeve 54 is connected to a base element 51 and said sleeve and base are slidably held in the socket shown in the die support 53. A coil spring 58 rests upon the block 51 and supports the enlarged lower end 56a of the pilot pin 56 holding said pin up. The inner sleeve 55 has a coil spring 59 mounted beneath a portion of said sleeve, said spring normally urging the sleeve upwardly. As will be seen in Fig. 6, the upward movement of the sleeve 55 is limited by an internal shoulder 60 formed in the outer sleeve 54.

The spring 58 beneath the pilot pin 56 is preferably a weaker spring than the spring 59 beneath the inner sleeve 55. Thus when rivet stock is pressed downwardly by the upper die plunger 46, it will press the lower rivet pin 56 downwardly and the inner sleeve 55 will remain up until pressure is exerted thereupon by the upper die 48. The pin 56 is adjustably limited in its downward movement by a stop 6I whose lower end is threaded in the block 51, but it is preferred that the pilot pin 56 coincide with the concave seat 62 in the inner sleeve 55 when both elements 55 and 56 are completely down. This position is provided to form a half round head on the lower end of the rivet.

When a piece of rivet stock has been cut oi and fed through the channel 5I to the bore 58 in the upper die 48, the upper die plunger 46 will have descended and will press the rivet stock through a pre-formed opening in the plates P which are to be riveted together. The plunger 46 will press the rivet stock downwardly until the lower end protrudes through the plates pressing the lower pilot pin 56 downwardly and the upper die 48 will press downwardly on the plates P and on the inner lower die sleeve 55 until both said sleeve and the pilot pin 56 are down. Since both ends of the rivet stock protrude from the plates P, the additional metal will be upset providing heads at either side of the plate which will be shaped by the concavities in the upper and lower dies. It will be seen that the plates P which are being riveted are held tightly together during the formation of the heads, and there is no opportunity for rivet stock to flow in between the plates and spread them apart.

On return or upward movement of the upper die and its carrier mechanism, the stack feed lever 26 will return approximately to the position shown in Figs. 1 and 2, and the feed dogs 25 will engage the teeth in the cooperating ratchet gear 22. The companion ratchet gear 2|, as best shown in Fig. 4, has a pawl 2Ia which is pivotally secured to the main casting 8. The ratchet and pawls 2I and 2Ia prevent the drag of the pawls 25 from rotating the feed roller I6 in a reverse direction. The locking of the feed roller IIB against reverse movement prevents said roller from moving the rivet stock rearwardly since such movement of the stock would vary the size of thevstock cut oi on the next downward stroke of the rack 38 and the stock cutter 45.

For feeding a new length of wire into the feed rolls and cutting mechanism I provide a hand wheel Ia on one end of the shaft I9 which carries the feed roll I6. With this hand wheel it is possible to rotate the feed roll I6 to feed wire from the two feed rolls into proximity with the cutter.

In some instances two pieces of metal are riveted together with two or more spaced rivets to Iprevent the riveted parts from twisting relative to each other. I have found that with my riveting apparatus it is Ipossible to utilize only one rivet in place of two in such a manner that two riveted parts are not capable of relative twisting movement. In carrying out this riveting method I insert a cut piece of riveted stock into apertures in the parts being riveted, and I form the apertures in any desired noncircular shape. The apertures may be oval, square, or some other noncircular shape. The rivet stock utilized for this purpose is a little longer than that ordinarily needed for the usual rivet connection. After the stock is inserted through the parts to be riveted, axial pressure is applied inwardly from the ends of the stock and the material of the rivet is forced outwardly laterally to lill up the noncircular openings in the parts to be connected. At the same time, the application of pressure with suitable dies forms heads on pposite ends of the rivet. Thus in one pressing operation it is possible to form a rivet connection which will lprevent one riveted part from twisting relative to the other. This method of riveting is particularly adaptable when connecting relatively light parts which are not subject to extraordinary twisting strains.

From the foregoing description it will be seen that I have provided a riveting machine by means of which rivets canbe formed from a relatively long wire of rivet stock and wherein the stock feed mechanism, the cutter, and the head forming dies are all synchronized so that riveting operations can be carried out relatively cheaply and with great speed. By actual test the apparatus can be operated at a greater speed than it is Ipossible for an operator to bring the opening through the parts to be riveted into proper coincidence with the line of movement of the rivet stock as it is fed from one die to the other. The machine can be adjusted for different lengths of die movement and the `feed can be so regulated that different lengths of rivet stock can be cut off to suit various thicknesses of material and other conditions which may arise. I have also devised an extremely advantageous method of riveting to prevent twisting of one part relative to the other after the riveting action wherein there is a considerable saving in the amount of rivets needed to prevent said twisting movement.

It will, of course, be understood that various changes may be made in the form, details, arrangement and pro-portions of the various parts and in the steps of the method without departing from the scope of my invention.

What is claimed is:

1. In a riveting machine, means for feeding a continuous strand of wire, a die unit comprising a pair of relatively movable elements, one of said elements having a stand cutter associated therewith, and said die unit elements being geared t0- gether for synchronous movement at different rates of speed.

2. In a riveting machine, a stationary frame portion having an opening therein, means for feeding a continuous strand of Wire through said opening, a die unit comprising an outer telescoping member movable with respect to said stationary frame and including a cutter adapted t0 cut said continuous strand of wire into pre-determined lengths, an inner telescopingdie element, gear racks on said stationary frame and on said inner telescoping die element, and a pinion mounted on said outer telescoping die element and meshing with the racks on said stationary frame and said inner telescoping die element.

3. In a riveting machine, a reciprocating drive unit, means for progressively feeding a continuous strand of wire rivet stock, said strand feeding means having an operating connection with said reciprocating Idrive, a movable die unit having an operating connection with said drive, and the connection between said drive feeding means and said strand drive means being adjustable to vary the progressive feeding movement of said feeding means.

4. The structure in claim 3 and said strand feeding means including a pair of feed rollers, a spring device for urging said rollers together, and a strand feeler operable to release the tension of said spring device when the end of a strand passes said feeler.

5. In a riveting machine, means for feeding a continuous strand of wire, a die unit comprising a pair of relatively movable elements, one of said elements having a strand cutter associated therewith, and said die unit elements being interconnected for synchronous movement at different rates of speed.

WALTER R. LINDSTROM.

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