US2400741A - Sewing machine - Google Patents

Description

May 21, 1946.

N. v. HRlsTENsEN ETAL SEWING MACHINE Filed April l2, 1943 4 Sheets-Sheet l I INVENToRs y 0R/wmv u cfmzsre/vsf/v BYVcgoRGE .sa UER RN v .Q

Q\ QM. hw

HTTRNE May 21,1946.

N. v. cHRlsTL-:NSEN Erm. 2,400,741

SEWING MACHINE Filed April l2, 1943 v INVENTORS NUR/VHN V. CHRSTENSf/V BY HUER HTT RNEY Mayzl, 1946. NJ cHRlsTENsN Erm. 4 2,400,741

SEWING MACHINE Filed 'April 12, 1943 4 Sheets-Sheet` 3 l N Il, mi 4 TNU N mmm mb m55 f RM H C0 .E VG .Y Nw, I l AY ..11 MB {IMI} P. W w w A -10,0 -ws /NN Nw uw m A l MN .9h hb... Qm- HN bwl .ww

Arran/v Y May 2l, 1946.

INVENToR. NORM/LN MGHR IS TENSE/V BY '0 GEORGE snc/ER Patented May 2.1, 1946 SEWING MACHINE Norman V. Christensen, Chicago, and George Sauer, Berwyn,

Ill., assignors to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Application April 12, 1943, Serial No. 482,690

(Cl. Ilz-218) 44- Claims.

This invention' relates to improvements in construction and method of operation of a sewing machine, embodying a rotary loop-taking element, and associated devices. It has particular reference to provisions for increasing the eiliciency and permissible speeds of operation of such machines.

A primary object of the invention has been to provide for the effective cooling or prevention of overheating of the stitch-forming devices of amachine of the character indicated and to prevent undue wear of such devices in the course of normal operation of the machine.

Another object has .been to provide simple and inexpensive means for thev purposes indicated. capable of producing the desired results without any appreciable addition to the cost of opthe lubricant to form, in effect, a lapping comv will now be given in conjunction with vthe accome eration of the machine or the power required l for such operation.

Heretofore, in the operation of machines having rotary hooks, several objectionable condi;

tions have arisen to limit the permissible speed of operation of the machine and reduce its norma1 life. Thus, there has been a tendency in high speed operations to develop excessive heat in the needle or in the hook, or both. When the needle becomes overheated there is danger of thread scorching and breakage as well las deterioratlon of 'the needle itself. overheating of the rotary hook renders the raceway lubricant less 30 the operative end of the needle whenever the latter is below the work., The cooling air, sodirected in a most effective manner, is derived, in accordance with the invention, from a blower driven by the motor which operates the sewing machine and the latter arrangement is such that no appreciable extra load is placed upon the motor.

Moreover, the blast of cooling air is of such character and so directed as toaccomplish various additional beneiicial results. move from the rotary hook and the adjacent portions of the machine the small bits of lint which normally have a tendency to accumulate on these parts and induce wear as well as prevent pound. In dealing with fabrics which are loaded particularly heavily with clay or the like, it is usually desirable to eliminate the lubrication of the hook raceway and at such times the cooling action of the blast of air and its tendency to clear away the particles of dust and lint are especially important.

Other objects, features and advantages of the invention will appear from the detailed description of an illustrative form of the same which panying drawings, in which:

Fig. I is a view, partly in side elevation and partly in vertical section, of a sewing machine and its power driven means and associated devices,Y all shown as mounted upon a supporting table and constructed and arranged in accord- Fig. II is an end view of the construction shown in Fig.v I as viewed from the right.

It serves to rev.

Fig. III is an enlarged detail view showing, in bottom plan, a portion of the construction illustratedin Fig. I, parts of the sewing machine being illustrated in section.

Fig. IV is a' face view of the rotary hook embodied in the illustrative machine and discloses the relationship between the hook and cooperating needle at a point in the cycle of operation of .l

the machine, and

Figure V is an enlarged detail view showing in side elevation the relationship between the ro.

tary hook, the needle, and the throat plate in the course of stitch formation, the throat plate being shown in section'. l Referring now to the drawings, the inventionV has been shown as applied to a lock stitch sewing machine of the type disclosed in the patent to Christensen et al. No. 2,113,572, granted April 12, 1938. This machine comprises a base portion I 0 providing a work supporting surface which is substantially flush with the surface of the top Il of a supporting table. The base, as will be understood, is mounted in an opening or recess in the table top-and may suitably be hingedly mounted on the latter or may simply be pm vided with a flange carried by the peripheral edge of the table opening. Rising vertically from one end of. the base l0 is a vertical standard I2 cardle bar I5 is mounted in the needle head and carries at its lower end a needle I6 constituting a part of the stitch forming instrumentalities. A

-presser foot I1 of suitable construction is mount- -ed at the lower end of a presser bar I1a, which `is also sli'dably mounted in the needle head and is urged yieldingly downward by an appropriate spring (not shown). For the purpose of operating the needle bar, there is provided within the arm I3 a-longitudinally extending shaft I8, the end of which projects beyond the vertical standard I2, as shown in Fig. I. To this shaft may be secured the conventional hand wheel and pulley la'through which power is supplied to the various operating devices of the machine.

As disclosed-in said Christensen et al. patent above mentioned, suitable gearing may be provided between theshaft I8 and a shaft I9 (Fig. III) which extends longitudinally of the base I9. Shaft I9 carries suitable eccentric means cooperating with an eccentric strap 29 and an arm 2i appropriately connected with the work feeding devices of the machine for imparting the feed movement and the lifting and lowering movements to the feed dog. The latter, which is not shown, may be suitably mounted upon a feed bar 22, which is given the desired movements by the ,eccentric means'mentioned above, in the manner `more fully set forth in said Christensenet al. patent. At an intermediate point there is secured `to the shaft I9 a gear23 which meshes with a pinion24 secured to a hook shaft 25 mounted in a long bearing sleeve-28carried bythe frame of the machine base. The gearing23 and 24, which is enclosed in an oil-tight housing, as illustrated in Fig. I, iissuch as to impart two revolutions to the shaft 2li4 for each revolution of the shaft I9 and for each reciprocation of the needle bar I5. At its forward end the shaft 25 carries a rotary i component 21 of a conventional two-to-one rotary hook. Within the rotary component there is mounted a stationary component 28 constitutmanner disclosed in the pending application of George Sauer, Ser. No. 442,585, led on May 12, 1942. The mounting may include a plate 34 secured to the top of the housing 33 and having a downwardly extending arm 35 (Fig. II), which is connected by a pivot (not shown) with a downwardly extending arm 36 integral with' a plate 31 secured t0 the under surface of the table top. A

bolt 38 pivoted upon the plate 31 and cooperating with a forked extension of the plate 34 may serve to retain the motor and clutch unit at a desired elevation to provide proper tension on the driving belt, to be hereinafter described.' i

-The shaft 39 of the motor extends into the clutch housing 33 and carries adjacent its end a flywheel 49 forming the driving element of the clutch. Axially alined with the shaft 39 is a driven shaft 4I carrying a' driven element 42 of the clutch. Shaft 4 I `is mounted insuitable bearings within a sleeve 43 carried by an extension 44 of the housing. The arrangement is such that the sleeve V43 may be shifted axially to a limited extent within the support 44. For this purpose pins or projections 45 carried by the sleeve 43 may extend through elongated openings in the portion 44 of the housing and may be engaged by the forked, upper ends of a, bifurcated portion of an operating lever 46 pivoted at 46a upon the clutch housing. A spring 41 normally urges the lever 46 in a clockwise direction (Fig. I) to shift the sleeve II3V toward the 4right and disengage the clutch. 'I'he lever 46, however, may b`e rocked'in a counter-clockwise direction in any suitable way, as by means of a link 48 connected with a foot treadle.

or thelike, to bring about engagement of the clutch at will.

Secured to the shaft 4I, which is shifted in the manner explained, is a pulley 4'9 connected by a ing ya. bobbin holder,` this being held against rotation by a detent 29 (Fig. III) secured to the under side of the work support. As will be understood, the hook illustrated is of the raceway type, in which a suitable rib provided on the stationary component cooperates with a groove or raceway in the rotary component. Any suitable means may be employed for lubricating the raceway.

For this purpose there is partially illustrated ln Fig. III a lubricant reservoir 30 mounted beneath the work support and having one end fitted over the,end of a bearing'sleeve 3| in'lwhich the end vof the hook shaft 29 is ioumaled. This construction may be of the type illustrated in the application of John G. Attwood, Sen-No. 473,804, filed 'on January 28, 1943. As disclosed in said application, the construction' maybe such that oil may be fed from the reservoir 39 through a longitudinally extending bore within the shaftv 25 to v the rotating component ofthe hook, which upon revolution will cause the `oil to be delivered to the raceway. 1

-For the purpose of driving the sewing machine, there may be' provided beneath the supporting table II an electric motor 32 having associated g ,therewith a power transmitting clutch housing 33. This transmitter unit may suitably be of the type disclosed in the-Patent No. 2.0372844. granted to Max Y'I'. Voight on April 14. 1936. and it may be mounted on the under side of the table top in the belt Bli'with the pulley Isa secured to the main drive shaft I8 of the sewing machine. Power is thus transmitted to the sewing machine from the motor 32 whenever the clutch is engaged by the axial shifting of the shaft 4I and clutch member 42. A supporting plate or frame 5I, preferably of c-shape, as; shown in Fig. II, is adiustably mounted on the clutch housing by a plurality of bolts 52. As set forth more fully in the pending Sauer application, above mentioned, this construction is such vas to permit both angular and axial adjustment oi the plate 5I with respect to the axis of the shafts 39 and 4I. A blower housing 53, preferably of the construction set forth in said Sauer-application, is detachably connected i ment o'f the clutch. The adjustment ofthe plate Y 5| in the manner above indicated, allows for the relative shifting of the impeller andblower housing` to eliminate interference between these parts. both in the original assembly of the parts andlby way of compensation for wear.

'I'he blower housing has an outlet member 59 which is connected. preferably, by a vflexible coupling 89. formed of rubber or a suitable synthetic composition, with the lower end of a tubular conduit 8 I The latter, which may suitably be formed of metal or an appropriate plastic or may simply be a exible hose, preferably, has an internal diameter of about 3/4 oi aninchand is shaped or bent, as indicated in Figs. I and II, to extend horizontally along the rear edge oi the table top',

or, V1i! desired, it may be positionedbeneath the table top or within a groove in the under surface side of the table along its rearward edge. Beyond the bracket 63 the tube or conduit is ,bent through a sweepingly curved portion 64 in such a way as to point its free end in the opposite direction. Another loop or bracket 65 may be employed to hold a portion oi the tube, adjacent its free end,

against the under surface of the table. The dis-` charge end 66 of the conduit has an outlet of the same' diameter as the conduit as a whole and is so positioned as to direct the stream of air ,generated by the blower against the outer face of the rotaryhook. Preferably, as shown,'the discharge end of the conduit is directed upwardly and inwardly at a slight angle. The appropriate inclination to the horizontal maybe established by cutting away the under surface of the table along the edges at one corner of the opening through which the base of the sewing machine extends, as indicated at 61 (Figs. I and III) and providing a sloping under-surface 68 V(Fig. I) at the desired angle on the portion of the table engaged by the discharge end of the conduit just in advance'oi the cut away portion. The spacing of the outlet 66 from the face of the rotary hook is preferably about 2 or 3 inches which is just sulcient to provide ready access to the hook and permit the removal of the bobbin holder 28 from the rotary component 2l without disturbing the relative positioning of the parts. This is facilitated, furthermore, by the location of the outlet 66 at one side of .the axis of the hook shaft, as shown in Fig. III, The arrangement is preferably such that the sewing machine as a whole may be swung backwardly on its hinges or lifted from the opening in the table, to permit access to the base of the machine, without disturbing Athe conduit. Due to the spacing indicated, between the outlet 66and the face of the hook, the stream of air discharged from the conduit is permitted to expand in the manner shown by the arrows in Figs. I and III and, thus, complete envelopment of the rotary hook is insured. A number of desirable effects are accordingly produced. Firstly, the temperature of the hook is kept within desirable limits; secondly, the accumulation of lint and iiller material on and within the hook is prevented; thirdly, the needle is subjected to a desirable cooling action whenever the point is carried below the work, and fourthly, lint and ller are blown away from the openings 69a and 69h (Figures IV and V) in the throat plate 38 through proper reception of the loop-seizing beak of the' rotary hook. This is illustrated in Figure V. The needle in this figure is'illustrated in the position -it assumes immediately after it commences its upward movement. This upward movement tends to'form a loop 10 in the needle thread. Im-

mediately thereafter the thread-seizing point, or

beak 1l of the hook enters the loop and thus causes the n'eedle thread to be cast aroundthe bobbin case. The air blown in the direction con,-` templated by the present invention serves to open up the loop 10 by blowing this toward the right in Figure V .away from the needle. Thus proper cooperation between the hook point 1| and the loop 10 is insured. If the blast of air were blown in the opposite direction it wculd'be seen from Figure V that it would tend to close the loop 'ill and thus interfere with the proper cooperation ofthe hook point 1 I with the loop. The same may beV said with respect to a blast of air directed upwardly from beneath 4the hook, since this passing around and through the openings in the hook will have a tendency to cause the loop 10 to ilatten out against the needle.

It has been found desirable to discharge the continuous stream of cooling air at a velocity of between 10 and 100 ft. per second and preferably between 50 and 70 ft. per second. In the use of a conduit of the character indicated an adequate amount of air, say between .1 and .3 of a cubic foot per second, may be delivered to the hook with a pressure in the conduit of only about 1.3 inches of` water above atmospheric. Discharge,l in the manner indicated, of the relatively low velocity and low pressure air through a space of rather large cross-sectional area has been found to impart a substantial cooling effect to th hook' and to bring about a quite substantial reduction in the temperature of the needle. It may be noted, `in this connection, that the needle is in a position in which its pointis accessible to the cooling air, as shown in Fig. IV,\for a substantial portion, i. e.,

. fully one-quarter, of each cycle of the machine.

The elimination of lint on and around the rotary hook and from the passages inthe throat plate y' -eiect of a coating of lint and dust which has a tendency to accumulate on the hook.

While. a preferred form of apparatus embodying the invention and a preferred mode of operation have been explained in detail in the .foregoing itwill be understood that numerous variations may be employed in the speciiic construction and arrangement of the parts and 4in the mode of attaining the purposes of the invention without departing from the general principles and scope of the invention. The terms and expressions used herein have been used as terms of description and not of limitation.

" We claim:

l. A machine of the class described comprising a work supporting member, needle carrying and operating mechanism arranged to carry a needle to and through work on said supporting member, a rotary hook having a bobbin holder beneath said member cooperating with said needle in stitch formation, means associated directly with said machine and including an electric motor and connections therefrom for driving said needle operating mechanism and said rotary hook a blower associated with said electric duit being xed at only a suillcient distance from said hook to enable ready access thereto for the removal of said bobbin holder. i

2. A machine of the class described comprisling a work supporting member,y needle carrying and operating mechanism arranged to carry a needle to and through work on said supporting member, a rotary hook beneath said 'member co- A Ioperating with said needle in stitch formation, a

power unit associated directly with said machine and including an electric motor and a clutch, connections from said unit to said machine for driving said needle operating mechanism and said rotary hook, a blower mounted on said power unit and arranged to be driven thereby to create a low pressure stream of cooling air at a velocity between and 10G feet per second, and a conduit from said blower to a point adjacent said rotary hook for delivering said stream of cooling air and directing the same substantially normal 3. A machine of thenclass described compris-` ing a work supporting member having a throat on. said power unit and arranged to be driven Y thereby 'to create a low'pressure stream of cooling air at a velocity between 10 and 100 feet per second and a conduit fromsaid blower to a point adjacent said rotary hook for'delivering said stream of cooling air and directing the same against 'the forward face of said hook, the discharge end of said conduit being fixed and spaced from said hook only a sufficient distance vto provide ready access to said hook, and being directed substantially axially of said hook but upwardly at a small angle toward the under side of the throat plate, thereby creating a slight outward pressure through said throat plate.

4. In apparatus of the class described a supporting table, an opening through the' top there-y of, a sewing machine supported by said table top and having a base portion adapted to extend through said opening, said machine having a throat plate 'and stitch forming devices including a needle `arranged to pass through said 'plate and a horizontal axis rotary hook exposedbeneath said table top, a motor and clutch unit carried by said table beneath said top, driving connections from said unit to said sewing machine for operating the latter, a blower carried by said unit and driven thereby to create a low pressure and low velocity stream of cooling air, a conduit connected with said blower extending beneath said table top to a point in front of said hook, the discharge end of said conduit being iixed and directed upwardly at a small angle not exceeding 30 to the horizontal substantially in the plane plate, needle carrying and operating mechanism arranged to carry aneedle to and through work o'n said supporting member and then through said throat plate, a rotary hook beneath said member cooperating with said needle in stitch formation, a power unit associated directly with.

said machine and including an electric motor and a clutch, connections from said unit to said machine for driving said needle operating mechanism and said rotary hook, a blower mounted of the axis of said hook and arranged to direct said stream of cooling air toward and against the forward face of said hook and around the same and indirectly through said throat plate, said hook being sutliciently open at its forward face to provide access of said cooling air to the needle at times. NORMAN V. CHRISTENSEN.

GEORGE BAUER.

Images