US1946870A

US1946870A - Helical spring coiling device

Info

Publication number: US1946870A
Application number: US604214A
Authority: US
Inventors: William H Moon
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-04-09
Filing date: 1932-04-09
Publication date: 1934-02-13
Anticipated expiration: 1951-02-13

Description

Feb. 13, 1934. w. H. MOON HELICAL SPRING COILING DEVICE Filed April 9, 1932 INVENTOR. W/u/flrr M00! BY KM f M Z0 ATTORNEYJ.

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Patented Feb. 13, 1934 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to a device for coiling helical springs. The said device is particularly useful as an attachment for a bed spring weaving machine but is equally useful in winding helical springs for other uses.

Inthe manufacture of woven bed springs, it is important that the helical coils which make up the spring be made with extremely accurate pitch and diameter since each spring must be woven into mesh with adjacent springs. If succeeding coils are not wound with substantially the same pitch, it is impossible for each turn of a coil to be fed into engagement with the corresponding turn of the preceding coil. This is particularly important where the coiling and weaving devices are part of a single machine, the coils being fed from the coiling device directly into engagement with the preceding coils without manual guidance. However, it is also of great importance where the coiling and weaving are done at two different operations. The accuracy of pitch must be maintained in the latter case as well as in the former. The present invention has for its object the production of a device which winds relatively long helical springs with an accuracy of pitch and diameter heretofore impossible.

The principal feature of the invention by which this result is accomplished resides in the provision of a relatively stationary mandrel about which is placed a rotating sleeve. The spring wire is fed between the sleeve and the mandrel and is bent about the mandrel by the frictional engagement of the wire with the'internal surface of the sleeve. A relatively large number of coils are maintained between the mandrel and sleeve surfaces so that the frictional action of the sleeve upon the wire is maintained for a suflicient time to remove all tendency for the spring to change form when it is released from the mandrel.

Another feature of the invention resides in the provision in the outer surface of the mandrel of a helical groove into one end of which the wire is fed. The rotatable sleeve closely engages the outer surface of the mandrel so that the spring wire is confined within the groove. The groove is cut with the helical pitch which it is desired that the finished spring shall assume and suflicient turns are made about the mandrel to remove any tendency for the spring to assume a different pitch when released from the mandrel.

Another feature of the invention resides in the fact that the mandrel is made larger in" diameter at one end than at the other. The spring wire is fed to the larger end and thus assumes the final diameter in a gradual manner. The initial bending effect of the sleeve upon the wire is thus distributed over several turns so that a coil may be formed having a smaller diameter than could be formed if the initial bending effect were confined to a single turn.

Another feature of the invention resides in the fact that the rate of rotation of the rotatable sleeve is such that the internal surface of said sleeve in contact with the wire assumes a linear velocity greater than the rate of advance of the wire. Thus the frictional effect of the sleeve upon the wire is much greater than would be the case if the said velocities were equal.

Other features of the invention will be understood from the accompanying drawing and the following description and claims:

Figure 1 is an end elevational view of the device with parts cut away to show other parts in detail. Herein the device is shown as an attachment to the frame of another machine, such as a bed spring weaving machine, but the scope of the invention is not to be limited by such showing. Figure 2 is a horizontal sectional view taken on the line 22 of Figure 1. Figure 3 is a vertical sectional view taken substantially on the line 33 of Figure 2. Figure 4 is a side view of a preferred form of the mandrel used.

The device is herein shown carried by a housing 10 which forms a part of the frame of a machine such as a bed spring weaving machine. The said housing is fitted with a cap casting 11 fastened thereto by cap screws 12. A cylindrical member 13 is clamped in a suitable opening between the housing 10 and the cap 11 and a ball bearing 14 is similarly clamped opposite thereto. A similar ball bearing 15 is retained by a set screw 16 in the cylindrical member 13. The said ball bearings rotatably support a sleeve 1'7 carrying an internal sleeve 18 fastened therein by means of a screw 19. A mandrel is formed with a shank 20 closely fitting within the sleeve 18 and a portion 22 extending into the cylindrical member 13 and locked therein by means of a set screw 23. The shank portion 20 of the mandrel is formed as best shown in Figure 2 with a helical groove 24 cut in its outer surface. This portion of the mandrel is larger at its left end than at its right end and tapers downwardly from the left over the length of several turns of the helical groove. A collar 21 is fitted within a recess in the cylindrical member 13 and is locked therein by means of a set screw 21a. .A hardened guide bushing 25 extends through a suitable hole in the cylindrical member 13 and the inner end thereof enters the collar 21. The guide bushing 25 is formed with a central passage 20 which is continued by a passage 27 in the collar 21. The passage 27 communicates with the end of the helical groove 24. A pair of feed rolls 28- are suitably mounted in position to guide a wire 29 into the guide bushing 25. The said feedrolls are power driven by a suitable connection with the machine to which the device-is attached and serve to regulate the rate of feed of the wire 28.

The sleeve 17 carries a spiral gear 30 fastened thereto by means of a key 31. Thegear 30 meshes with a spiral gear 32 carried upon a shaft 33, one end of which is supportedv by a ball bearing 34 carried by the cap 11. The opposite end of the shaft 33 is suitably supported within the machine to which the device is attached and the said shaft is rotated by rotating portions of said machine.

In the operation of the device, the spring wire is fed between the rolls 28, through the

guide passages

26 and 27 and into the helical groove 24. The sleeves 17 and 18 are rotated by means of shaft 33 and

gears

30 and 32 in the same direction as the advance of the wire through the helical groove 24. The speeds of rotation of the feed wheels 28 and the sleeve 18 are such that the internal surface of the sleeve 18 rotates with a greater linear speed than the linear speed of advance of the wire. It is to be noted that while the frictional effect of the-feed wheels 28 is suflicient to regulate the rate of movement of the wire, it is not ordinarily sufficient in itself to advance the wire through the helical groove 24. The balance of the force necessary to advance the wire is supplied by the friction of the sleeve 18 because of the excess in the speed of said sleeve. The frictional effect of the said sleeve on the wire winds the same firmly about the mandrel 20 within the groove 24. The length of the mandrel is so chosen that when the wire reaches the end thereof, all tendency for the wire to assume a coil diameter or pitch other than that of the helical groove 24 has been overcome. The helical spring so formed is, therefore, so accurate in pitch and diameter that it may be fed directly into engagement with the spring last woven into the bed spring without manual or mechanical guidance.

It is also to be noticed that the construction of the device is such that mandrels of different sizes and pitches may be easily interchanged. When a mandrel of a different diameter is to be used, it is only necessary to substitute a corresponding internal sleeve 18 without disturbing external sleeve 17. When left hand coils are to be wound, the cylindrical member 13 is replaced by one having the guide bushing 25 leading to the upper edge of the mandrel shank instead of the lower, as shown herein. A mandrel having a left hand helix cut therein is then used and the direction of rotation of the sleeve 18 is reversed by suitable reverse mechanism or by replacing the

gears

30 and 32 with an oppositely rotating pair of similar gears.

While a preferred form of the invention has been specifically disclosed herein, variations from the details thereof may be made without departing from the scope of the invention as defined by the following claims.

The invention claimed is:

l. A spring coiling device including a mandrel having a. larger diameter at one end than at the other, a rotatable sleeve surrounding said mandrel, means for feeding spring wire between said mandrel and sleeve at the large end of said mandrel, and means for rotating said sleeve to wind said wire about said mandrel.

2. A spring coiling device including a mandrel having a larger diameter at one end than at the other, a rotatable sleeve surrounding said mandrel, means for feeding spring wire between said mandrel and sleeve at the large end of said mandrel, and means for rotating said sleeve at a speed which imparts to its internal surface a linear speed at least as great as the rate of feeding of said spring wire to wind said wire about said mandrel.

3. A spring coiling device including a mandrel having a larger diameter at one end than the other and having a helical groove. in its outer surface, a rotatable sleeve surrounding said mandrel and closely fitting the same, means for feeding spring wire into the end of said helical groove at the large end of said mandrel, and means for rotating said sleeve to wind saidwire about said mandrel.

4. A spring-coiling device including a mandrel having a larger diameter at one end than the other and having a helical groove in its outer surface, a rotatable sleeve surrounding said mandrel and closely fitting the same, means for feeding spring wire into the end of said helical groove at the large end of said mandrel, and means for rotating said sleeve at a speed which imparts to its internal surface a linear speed at least as great as'the rate of feeding of said spring wire to wind said wire about said mandrel in said groove.

5. A spring coiling device including a mandrel having a larger diameter at one end than at the other, a rotatable sleeve surrounding said mandrel, means for guiding spring wire between said mandrel and sleeve at the large end of said mandrel, and means for rotating said sleeve to wind said wire about said mandrel.

6. A spring coiling device including a mandrel having a larger diameter at one end than the other and having a helical groove in its outer surface, a rotatable sleeve surrounding said mandrel and closely fitting the same, means for guiding spring wire into the end of said helical groove at the large end of said mandrel, and means for rotating said sleeve to wind said wire about said mandrel.

WHLIAM H. MOON.