US2576961A - Thread waxing device - Google Patents

Description

Dec. 4, 195] J MCCARTHY 2,576,961

THREAD WAXING DEVICE Filed April 8, 1949 Patented Dec. 4, 1951 UNITED STATES PATENT OFFICE THREAD WAXING DEVICE John F. McCarthy, Lynn, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application April 8, 1949, Serial No. 86,349

2 Claims. 1

The present invention relates to thread waxing devices adapted for use in shoe sewing machines and to improvements in strippers for waxing devices more particularly with regard to their case in adjustment and effectiveness during continued use. As hereinafter illustrated, the ex emplified Wax stripper is of the type disclosedin United States Letters Patent No. 1,015,772. granted January 30, 1912 upon application of Fred Ashworth.

The stripper of the patent above referred to is of desirable construction and comprises a perforated and compressible rubber plug supported in a split sleeve formed with one end open and a perforated wall at the other end. For mounting the sleeve it is enclosed loosely in a socket and cooperating therewith is a perforated compressor retained in position by a cap having a screw threaded engagement with the socket, the compressor being provided with a flat plug engaging surface acting directly at right angles to the length of the thread passing tliroughthe plug. The purpose of the patented construction is to facilitate removal and insertion of the compressible rubber stripper plug supported within the sleeve.

When the plug of the patent is first inserted within the split sleeve it is compressed by actuation of the compressor cap until the plug conforms closely with the thread passing through the perforation therein. The perforated plug of the patent has both ends cut squarely at right angles to the length of the thread. For this reason the frictional reaction of the thread on the compressible rubber of the plug tends to crowd together that end of the perforation in the plug first entered by the thread, compressing the thread sharply as it enters. As a result, the surplus wax on the thread is substantially all wiped off the outer thread surface by the compression of the plug material against the thread as it enters the plug, subjecting the plug around the perforation at the point of entry of the thread to maximum abrasion by the thread. Continued wear of the inner surfaces of the perforation requires frequent tightening of the cap and makes necessary an adjustment of the compressor cap to apply further pressure on the plug. Eventually the plug becomes so worn around its perforation that replacement is required.

The object of the present invention is to produce a thread waxing device having a compressible perforated stripper plug together with supporting means for the plug which will increase the durability of the plug, improve the waxing and stripping action on the thread and avoid the necessity of frequent adjustment of the compressor cap in the holder, while retaining all of the advantages of the waxing device disclosed in the patent. A further object is to reduce substantially the frequency of replacement for a stripper plug in a thread waxing device. The waxing device embodying the features of the present invention, accordingly comprises a stripper plug, a supporting sleeve and a compressor similar to those of the patent except that the end wall of the sleeve and the plug engaging end of the compressor are formed internally with conical recesses, the conical angle on the compressor end wall surface being substantially less than that on the end wall of the sleeve, in which a compressible-perforated plug is employed having tapered ends in its uncompressed condition, the angles of taper of which correspond to the conical angles in the sleeve end wall surface and in the compressor, respectively. By so forming the plug it fits accurately within the supporting sleeve under all degrees of compression. This is true both after the plug has been subject to substantial wear as well as when a new plug is first inserted in the supporting sleeve. The life of the plug as a result is increased many times over that of the plug in the patent and the stripper is effective in use without forcing the compressor against a new plug with any substantial degree of pressure, as is required in the patented waxing device. Furthermore, the thread, when it enters into the end of the plug having the greater conical angle and emerges from the end of the plug having the lesser conical angle, is waxed more effectively with the wax forced more deeply inside the thread and the surplus removed more completely from the surface than with prior strippers.

These and other features of the invention as hereinafter described and claimed will readily be understood from the following detailed specification taken in connection with the 'accompanying drawings, in which Fig. 1 is a view in front elevation of a wax pot embodying the waxing device of the present invention;

Fig. 2 is a sectional view on an enlarged scale of the waxing device and upper portion of the cover for the Wax pot illustrated in Fig. l;

Fig. 3 is a detail perspective view of a stripper plug split supporting sleeve illustrated in Fig.

.Fig. 4 is a detail view in half-section; partly diagrammatic, on a still'further enlarged scale of a portion of a waxing device having a stripper plug similar to that employed by the prior art illustrating its manner of o eration on the thread; and

Fig. 5 is a similar view of a waxing device cmbodying the features of the present invention.

The illustrated thread waxing device is intended for use in connection with a wax pot Iii through which a sewing thread I2 is passed in the direction of the arrows of Fig. l. The thread enters a tube I l mounted in a removable cover IE on the wax pot and after being submerged within a bath of liquid wax the thread is drawn through the waxing device including a perforated compressible rubber stripper plug 18. The stripper plug is supported within a split sleeve mounted in turn within an internal seat in an externally threaded socket 22. The socket 22 is clamped by a set screw 23 within an opening in the top of the wax pot cover It. To compress the plug against the thread the upper end of the plug is engaged by a compressor 24 loosely mounted in an internally threaded cap 26 engaging the threads on the socket 22. The purpose in supporting the plug in the split sleeve is to facilitate removal of the plug after its perforation has been enlarged to a point where it is no longer possible to force the plug into close conformity with the thread so that it is no longer capable of stripping the excess wax properly from the thread.

In the thread waxing device of the Ashwortn patent above noted the wax stripping plug is cut from an extruded length of rubber rod perforated to guide the thread with flat ended surfaces at right angles to the length of the thread guiding perforation passing through it. The ends of the sleeve and of the compressor engaging the plug are correspondingly shaped, the arrangement being such that the action of compressing the plug causes a maximum force to be concentrated against the surfaces of the thread at the point of entry of the thread within the perforation of the plug; For this reason the surplus wax is stripped from the thread at the point of entry of the thread within the plug, the greatest abrasional pressure on the thread being applied at this point. The natural result of the abrasional pressure of the plug on the thread is to indent slightly the material of the plug about the perforation, causing it to move along with the thread in a manner to increase still further the component of abrasional pressure against the thread. Frequently, a vibratory action of the plug on the thread occurs from this cause, centered around the point of entry of the thread and generally the inner surface of the perforation at the point of thread entry becomes worn rapidly, particularly after a new plug has been inserted in the waxing device. As soon as the plug becomes worn more pressure on the plug is required to strip the thread properly of surplus wax. Accordingly, the cap corresponding to 26 of Fig. 2 in the accompanying drawings is screwed down more tightly.

As illustrated in Fig. 4 a square ended stripper plug 28 is shown, the right-hand half having been omitted to avoid duplication. Although the plug supporting sleeve and compressor shown are those illustrated at 20 and 24 as in Fig. 2 having conical plug end engaging surfaces, the action of the illustrated sleeve and compressor is substantially the same as the flat ended ones of the patent.

Referring-to the diagrammatic portion of Fig.

4, the force of the compressor 24 is illustrated by a vector 30 and is shown as bein directed along a line running from the outside corner of the compressor 24. The vector 30 is met by a similar and substantially equal vector 32 drawn through the lower outer corner of the square ended plug 28 and representing the force at the end of the sleeve 20. The resultant of these two vectors is the force applied to the thread by the material of the plug around its perforation and is represented by a vector 34. The vector 34 is directed downwardly toward the point of entry of the thread l2 within the perforation of the plug 28. Since the movement of the thread is in an upward direction the frictional action on the thread tends to indent and thus increase the compression on the material of the plug, indicated by the curved surface 29 at the bottom of the plug and correspondingly the vibrational and wearing action on the plug is increased. Furthermore, the surplus wax is stripped from the thread at its point of entry and accumulates beneath the bottom surface of the plug 28 where it frequently builds up sufficient pressure to raise the wax through the split between the halves of the stripper sleeve 20 until the wax fills the recess within which the waxing device is located in the wax pot cover 16 and overflows the outer surface of the cover. This is particularly noticeable when a square ended stripper plug first is inserted in the waxing device. After continued use more and more pressure is required to bring the plug into proper stripping conformity with the thread. However, in compressing the plug its resiliency is substantially reduced so that it wears away in contact with the thread more rapidly than when first inserted and eventually fails to strip the thread properly with any degree of pressure. For these reasons it is necessary to replace the stripper plug at frequent intervals.

According to the present invention, the necessity of frequently replacing the stripper plug is avoided and an improved waxing action of the device on the thread results. To this end the stripper plug I8 is constructed to impart pressure to the thread in a particularly advantageous manner which requires far less compression to the plug than with prior plugs, especially when first inserted in the supporting sleeve. Instead of centering the application of pressure on the thread at the point of entry into the plug, the pressure of the plug I8 is centered nearer the end of the plug from which the thread emerges (see Fig. 5), the thread drawing surplus wax into the perforation in the plug to build up a hydraulic counter-pressure within the perforation. In this way the wax is forced between the superficial fibers of the thread. giving a deeper ime pregnation and avoiding abrasion of the inner surface of the plug perforation. Furthermore the pressure on the thread is distributed over a considerable area along the length of the thread, producing more of a wiping action than a scrap- 7 ing action as occurs in the stripper plug of the prior art. Also, the resultant of the endwise compression forces within the substance of the plug is directed upwardly toward the thread so that the tendency of vibration between the thread and the stripper plug is much less than when the resultant of the compressional forces in the plug is downwardly as in the prior art.

The wax stripper plug 58, illustrated in Figs. 2 and 5, has tapered ends 36 and 38 and a central axial perforation 40 through which the thread I2 is drawn from the wax pot I 0. The split sleeve 20 is formed with one end open but with an internal conical perforated wall at its lower thread entering end of approximately a 60 angle to the thread instead of having a square end as in the patent. The plug engaging surface of the compressor 24 at the thread emerging end of the plug is made internally in conical form disposed at approximately 45 to the thread and the compressor has a centra1 perforation through which the thread may be drawn from the plug. The plug has the angles of its tapered ends while in its uncompressed condition correspondingly shaped and proportioned to fit the conical angles of the sleeve end wall and of the compressor respectively, the angle of the compressor conical surface being substantially less by at least than that of the sleeve end Wall surface.

Referring to the diagrammatic part of Fig. 5, the direction and intensity of the force applied by the compressor 24 to the plug I8 when the thread enters at the lower end of larger conical angle is approximately represented by the vector 42. The corresponding reaction force of the end wall conical surface 36 of the sleeve is represented by the vector 44 and the resultant force is represented by the vector 46. It will be apparent from a consideration of the location and direction of the resultant vector 46 that the pressure on the thread running from the end of greater conical angle to the end of lesser conical angle will be concentrated just above the mid-section of the stripper plug. However, the surplus wax on the thread will not be removed entirely from the surface of the thread until the thread reaches the upper end of lesser conical angle on the stripper plug because wax will be drawn into the perforation at the end of greater conical angle, providing a hydraulic pressure which resists the inward pressure of the plug against the thread. For this reason the surplus wax will be drawn to a point substantially above the mid-section of the plu before actual contact occurs of the plug with the thread. Furthermore, the lower end of the plug fits exactly with the end wall of the sleeve and prevents any accumulation of liquid wax between the plug and the sleeve. Thus, there is no possibility of building up a hydraulic pressure in the wax beneath the plug such that the wax will be forced upwardly through the split between the halves of the sleeve 20. The wax also is forced into the inner fibers of the thread by the hydraulic wax pressure built up within the perforation. Since the pressure of the plug against the thread is distributed over a greater area than is the pressure in the plug of the prior construction and is resisted by the hydraulic pressure of the wax on the thread, much less pressure is required, less wear occurs from abrasion of the thread on the plug and the plug itself has a longer life in actual use.

To enhance the building up of hydraulic pressure in the plug and to exclude the pressure from the space between the lower end of the plug and the end wall of the sleeve 20 the ends of the plug are provided with internal depressions 48. The upper end is also similarly shaped to insure concentration of pressure on the thread more definitely at the upper end of the plug. With spective parts.

such construction of the plug not only is a more efiective thread waxing operation obtained but the useful life of the plug is extended six to eight times. Accordingly, it; is economical to mold each plug properly in a separate operation rather than to employ cut lengths of an extruded rod material with square cut ends. Also, it is advantageous to employ separately molded plugs because they are by reason of their molding operation of amorphous internal structure which provides a better wearing characteristic on the thread than is obtained by the extruded rod material. The extrusion operation tends to elongate the molecular structure of the rubber into a fibrous form, the fibers of which run lengthwise. Lengthwise fibrous structure does not provide such durable wearing surface engaging the thread inside the plug perforation as an amorphous structure, particularly where the abrasive action is in the same direction.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

l. A thread waxing device having a stripper sleeve formed with one end open and an internal conical perforated wall at the other end into which the thread enters, and a compressor disposed within the open end of the sleeve and formed at the inner end from which the thread emerges with a conical recess of an angle substantially less than the conical angle at the end wall of the sleeve, in combination with a compressible perforated wax stripper plug having in its uncompressed condition tapered ends of substantially diiferent angles of taper corresponding to the conical angles of the sleeve end wall and of the compressor, respectively, and disposed to fit the corresponding ends of the sleeve and compressor.

2. A thread waxing device having a split stripper sleeve formed with one end open and an internal conical perforated wall at the other end into which the thread enters, the conical angle of said end wall being approximately 60, an enclosing socket to receive the sleeve, and a compressor disposed within the open end of the sleeve and formed at its inner end from which the thread emerges with an internal conical surface having an angle of approximately 45, in combination with a compressible perforated rubber wax stripper plug having in its uncompressed condition tapered ends of the same angles of taper as those on the sleeve and compressor disposed to fit the corresponding ends of the re- JOHN F. MCCARTHY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 528,301 Montgomery Oct. 30, 1894 1,015,772 Ashworth Jan. 30, 1912 1,882,450 Tyner Oct. 11, 1932 1,943,818 Fantone et al. Jan. 16, 1934 2,020,783 Jones Nov. 12, 1935 2,036,048 Hinsky Mar. 31, 1936 2,357,168 Bruining Aug. 29, 1944

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