US1973201A

US1973201A - Thread rolling apparatus

Info

Publication number: US1973201A
Application number: US631982A
Authority: US
Inventors: Fassinger Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-09-07
Filing date: 1932-09-07
Publication date: 1934-09-11
Anticipated expiration: 1951-09-11

Description

p 1934- c. FASSINGER THREAD ROLLING. APPARATUS Filed Sept. 7, 1932 2 SheetsSheet 2 l/l/l/ l/l llll l INVENTOR [mi V thr Patented Sept. 11, 1934 UNITED STATES,

1'- OFFICE 3 Claims.

My invention relates to thread-rolling apparatusand a method of rolling threads, particularly in the threading of bolts, screws, spikes and the like.

In the threading of blanks, it has been common practice to so roll or forge the shank of a blank that the over-all diameter of the threaded portion thereof will be somewhat greater than the diameter of the original blank, owing to the fact that the threads are produced by pressing the teeth of the dies into the blank 2. distance less than the depth of the thread to be produced, the metal of the blank being displaced and caused to swell out into the spaces between the teeth to form the tops of the threads. The over-all diameter of the finished article is therefore somewhat greater than the original diameter of the bla One object of my invention is to so thread a blank that there will beno substantial displacement of the metal in a radially outward direction, and to produce threads which will be quite dense, and free from ruptures through excessive displacement of the metal contained within the ead. Another object of my invention is to provide means for rolling threads by commencing at a point adjacent to the head of the blank and progressing toward the point or inner end thereof, instead of applying the threading teeth to the blank throughout substantially its entire length at the beginning of the thread-forming operation.

Another object of my invention is to provide means for operating threading dies in such manner that danger of the blank slipping when initially engaged by the dies is minimized.

Still another object of my invention is to simplify and improve generally the methods of and apparatus for rolling threads.

One mannerin which my invention may be practiced is shown in the accompanying drawings, wherein Figure 1 is a plan view of a threading machine; Fig. 2 is a side elevational view thereof; Fig. 3 is a cross sectional view, on an enlarged scale; Fig. 4 is a sectional view. of a portion of the apparatus of Fig. 3, on a still further enlarged scale; Fig. 5 is a sectional plan view of the structure of Fig. 4; Fig. 6 is a view similar to Fig. 4, but showing a completely threaded spike in position between the dies;

Fig. 7 is a side elevational view showing one of the dies, and a partially rolled spike therein, and Fig. 8 is a plan view showing the spike beporting frame or base tween the dies at a Fig. 7.

The apparatus is shown as mounted on a sup- 10 wherein a shaft 11 is journalled, the shaft being driven from any suitable source of power. The shaft 11 carries a pair of

eccentrics

12 and 13, and a cam disc 14.

In the forward part of the frame 10

slideways

15 and 16 are provided, these slide-ways having suitable

steel liner plates

17 and 18. The slideway 15 is stationary while the slide-way 16 is periodically given some lateral movement by means of hell cranks 19 that have their inner ends pivotally connected to the slide-way 16 and their outer ends connected to a pull rod 20,

partially rolled stage, as in the intermediate portions of the bell cranks pivotally connected to the frame 10. By this, the slideway 16 has a lateral movement towards slide 15 at the beginning of each stroke, or cycle of the crankshaft, and also, a lateral movement away from slide 15 at the end of each stroke or cycle of the crankshaft, so as to facilitate engagement of the blanks and release thereof by the dies.

Dies

21 and 22 are removably supported on

slides

23 and 24 respectively, in any suitable manner, as by clamping brackets 25, the

slides

23 and 24 being held in position on their slideways by brackets or

clamping yokes

26 and 27 respectively. The

slides

23 and 24, of course, have sliding movement on the slide-

ways

15 and 16 as hereinafterdescribed, to effect rolling of threads on blanks.

The

slides

23 and 24 are operated by

eccentric rods

28 and 29, respectively, that are in turn connected to the

eccentrics

12 and 13, so that during rotation of the shaft 11'. the

slides

23 and 24, and the dies carried thereby, will be simultaneously reciprocated in opposite directions.

The cam disc 14'is of such contour that when the die 21 is in its foremost position and the die 22 at its rearmost position, as shown in Fig. 1, the rod 20 will be thrust forward to rock the cranks 19 in counter-clockwise directions to thrust the slide-way 16 toward the slide-way 15, thus gripping the blank 31 between the

die blocks

21 and 22, so that there will be no slipping of the blank about its axis at the beginning of the rolling operation.

At the instant the blank is gripped, as aboveexplained, the

eccentrics

12 and 13 reach such positions that the die block 21 begins to move backwardly, and the die 22 forwardly, and such movements are continued until the thread has been rolled on the blank 31. At the completion of the rolling operation, and preliminary to return movements of the dies, the raised surface of the cam disc 14 has passed out of engagement with the roller 33, whereupon the rod 20 is retracted by pressure of a spring 34 that operates against a nut 35 on the rod and a fixed stop shoulder 36 that is secured to the base of the machine, and which serves also as a guide for the rod 20. The bell cranks 19 will thereby be swung in a clockwise direction, shifting the slide-way 16 laterally from the slideway 15. The dies are then returned by the

eccentrics

12 and 13 to the positions shown in Fig. 1.

Another important feature of my invention resides in the form of the

dies

21 and 22, which is shown more clearly in Fig. 7. These die blocks are complementally formed, and have their thread-forming teeth formed in somewhat the usual manner, except at the entrance of the dies, their toothed portions are in effect tapered. through the fact that the teeth are inclined or lie in diagonal lines, and. are so positioned that only the upper portion of the blank is initially engaged by the teeth, the teeth being brought progressively into engagement with the shank as the rolling progresses.

The dies, during the rolling operation, are held so closely together that the teeth will penetrate full depth into the blank, so that little or none of the metal is extruded radially outward between the thread-rolling teeth. The metal displaced by the threading teeth is caused to flow longitudinally of the blank and causes elongation thereof. If desired, the dies can be brought so closely together that the over-all diameter of the threaded blank will be even less than the original diameter of the blank.

The operation described produces a threaded article wherein the metal forming the teeth has not been excessively distorted, and in fact may be considerably compressed to make for greater density and strength, and without minute ruptures that would weaken the teeth.

The blanks may be rolled either hot or cold, and the invention is of particular advantage in the rolling of railroad tie spikes and the like, where a considerable area of the spike is unthreaded at points between the successive thread turns.

While the thread-forming elements of the dies are herein referred oas teeth, it will be seen that because they are of a form to produce threaded spikes of wide pitch, the teeth are in efiect wide-faced ribs, between which are groove like spaces having approximately the cross sectional form of the completed thread.

I claim as my invention:-

. 1. Thread-rolling apparatus comprising a pair of spaced dies positioned to receive a blank, each die being provided with a full-size thread-forming tooth extending diagonally downwardly and rearwardly from a point adjacent to the upper forward corner thereof, to a point adjacent to the lowermost edge of the die, means for moving the dies toward one another a distance sufiicient to initially compress the blank between the said teeth to the depth of the teeth, previous to thread-rolling movement of the dies, means for maintaining this relative lateral position of the dies during the rolling operation, and means op- ,erating in timed relation to the first-named movement for moving the dies to effect rolling movement of the blank between the same.

2. Thread-rolling apparatus comprising a pair of laterally-spaced die blocks, dies carried thereby in position to engage a blank at opposite sides thereof, eccentric mechanism for reciprocating said die blocks to effect rolling of blanks between the dies, a bell crank device mounted at its mid point on a fixed pivot and connected at one end to one of the die blocks, a rod having connection with the other end of the bell crank, and a cam operating to shift said. rod in timed relation to movement of the eccentric mechanism, the said cam having a raised portion operating to rock the bell crank and bring said one die block toward the other, preliminary to the commencement of the rolling operation, the said raised portion being of such length as to maintain the spaced relation between th die blocks during blank-rolling movement thereof.

3. Thread-rolling apparatus comprising a pair of spaced dies positioned to receive a blank, each die being provided with a full-size thread-forming tooth extending diagonally downwardly and rearwardly from a point adjacent to the upper forward corner thereof, to a point adjacent to the lowermost edge of the die, and with successively-arranged teeth disposed in parallelism with the first-named tooth, means for moving the dies toward one another a distance sufficient to initially compress the blank between the said full-size teeth to the depth of said teeth, previous to thread-rolling movement of the dies, means for maintaining this relative lateral position of the dies during the rolling operation, and means operating in timed relation to the firstnamed movement for moving the dies to effect rolling movement of the blank between the same.

- CHARLES FASSINGER.