US3471902A - Means for counterbalancing the acceleration forces in rapidly oscillating machine members especially doffer combs - Google Patents

Description

FER COMBS 2 Sheets-Sheet 1 ON FORCES IN RAPIDLY AGCELERATI OSCILLAIING MACHINE MEMBERS ESPECIALLY DOF Filed April 25, 1967 Oct. 1969 J. A. LILJA ETAL MEANS FOR COUNTERBALANCING THE ATTYS.

1969 J. A. LILJA ETAL 3, 7

. MEANS FOR COUNTERBALANCING THE ACCELERATION FORCES IN RAPIDLY OSCILLATING MACHINE MEMBERS ESPECIALLY DOFFER COMBS Filed April 25, 1967 2 Sheets-Sheet 2 M5 M4 M0 J4 242 g @245 A\\\ W 6 4 [45 24. Z40

INVENTORSZ JOHN ALLAN LILJA AKE ESKIL LJUNGHOLM AT YS.

United States Patent Int. Cl. D01g /46 US. Cl. 19-406 1 Claim ABSTRACT OF THE DISCLOSURE A means for counterbalancing acceleration forces in rapidly oscillating machine members, for example, the acceleration forces in the oscillating comb of a doffer comb consisting of an elongated torsion bar secured at one end to a fixed support and fixedly connected at its opposite end to a shaft extension of a rock shaft in a doffer comb box. The torsion rod extends through an elongated bore in the dofier comb shaft being spaced therefrom and located on an axis eccentric from the axis of the doffer comb shaft.

This is a continuation-in-part application of our prior application Ser. No. 422,336, filed Dec. 30, 1964, now abandoned, for Means for Counterbalancing the Acceleration Forces in Rapidly Oscillating Machine Members, Especially Doffer Combs.

The present invention relates to improvements in mechanisms which have an oscillating member and more particularly to a means for counterbalancing acceleration forces in rapidly oscillating machine members. The present invention has particular application in the textile industry for use in carding apparatus. These carding apparatus generally include a doffer comb box having a crank mechanism which transforms the rotating motion of a crank shaft driven by the cylinder of the card to an oscillating motion of a rock shaft which in turn is connected to the doifer comb.

The deflection of the rocking shaft for a typical dofler comb box is 110. Accordingly when the crank shaft is rotated, the doifer comb oscillates with fixed turning points, the length of the stroke being constant and independent of the speed and being generally referred to as a guided motion type. The rocking and crank shafts are mounted in bearings and it has been found that the operating speed of the doffer comb assembly must be maintained below a predetermined level for example rotation of the crank shaft below 1800 r.p.m., in order for the bearing to have an acceptable life, for example 40,000 to 50,000 operating hours. It has been found that for high production cards it is necessary to operate the machine at substantially higher speeds and it has been found that moderate increases in speed resulted in acceleration forces which were so considerable that the doffer comb box bearings failed after a relatively short time. For example, when the speed of the crank shaft is increased, the bearing load will increase in proportion to the square on the speed rise and thus, when speed is increased for instance 11%, the bearing Working life will be reduced by half. Since it is desirable to drive the dotfer comb in high production cards at frequencies of about 3,000 strokes per minute or eventually even higher, it is obvious that the bearing life will be very short. Moreover, at the elevated speeds, vibrations in the doffer comb results in unsatisfactory web removal.

Accordingly, an essential requirement in cards used on high production machines is the accommodation of the considerable acceleration forces and the present invention provides a novel and comparatively simplified means for achieving this end.

To this end, according to the present invention there is provided for a mechanism having a member which oscillates when the member is in use, a spring member connected at one end to the oscillating member and held fixed at its other end, which spring is so dimensioned and connected in such a manner that the oscillation of the member causes a spring load to be applied to the oscillating member or such drive in opposition to the acceleration and retardation loads so that the net reaction on the bearings of the drive is reduced as compared with the same mechanism having no springs. More particularly, in accordance with a preferred form of the invention as it applies to a dolfer comb box, there is provided a torsion bar, one end of which is held fixed and the other end is connected to the crank shaft which drives the shaft extension which in turn mounts the doifer comb to oscillate therewith, the torsion bar being so dimensioned that the spring load which applies to the shaft opposes the acceleration and retardation loads of the doifer comb to an extent that the reaction load on the bearings of the shaft are reduced as compared with a doifer comb box of the same design but having no torsion bar.

It is noted that in the preferred form of the invention, the torsion bar extends through an elongated bore in the dofier comb shaft being spaced therefrom and located on an axis eccentric from the axis of rotation of the doffer comb shaft. It is by this arrangement that it is possible to achieve the desired reduction of harmful effect on the bearings mounting the crank shaft and rocking shaft in the dofier comb box. For example, with the arrangement of the present invention, it has been found that even at speeds of 3,000 r.p.m., the forces on the bearing are reduced to a point whereby the bearing life is increased 20 to 30 times and providing an acceptable working life of about 30,000 to 40,000 hours.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein:

FIG. 1 is a transverse sectional view showing a dofier comb box and dofier comb assembly including the preferred embodiment of the present invention;

FIG. 2 is a sectional view taken on line 22 of FIG. 1;

FIG. 2a is a sectional view taken on line 2a2a of FIG. 1;

FIGS. 3 and 4 are charts showing reduction in the acceleration forces in an assembly of the type shown in FIG. 1 embodying the present invention;

FIG. 5 is a view partly in section showing a second embodiment of spring biasing means in accordance with the present invention for a dofier comb assembly;

FIG. 6 is a view taken on lines 6-6 of FIG. 5;

FIG. 7 is an alternate embodiment of biasing means similar in some respects to the embodiments shown in FIGS. 5 and 6; and

FIG. 8 is a view partly in section showing a fourth embodiment in accordance with the present invention.

Referring now to the drawing and particularly to FIG. 1 thereof, there is illustrated a dofier comb assembly incorporating the present invention. The assembly includes a dotfer comb box generally designated by the numeral 10 which houses a rotatably mounted crank shaft 12 which in turn mounts at its inner end a pulley 14 which is driven by a belt transmission connected to the cylinder of a card (not shown). The crank shaft as illustrated is journalled in bearing assemblies 16 and 18 and mounts at its forward end an eccentric crank 20 which is rotatably journalled in a. connecting arm 22, the connecting arm being suitably pivotally connected to an arm 24 formed integrally with a shaft extension 26 of a rock shaft 28 journalled in bearings 29 and 31 in the doffer comb box 10.

The doffer comb assembly, generally designated by the numeral includes a dofier comb shaft 32 having reduced terminal end portions 34 and 36 and a plurality of supporting arms 38 at spaced apart points along the length of the shaft 32 which mount the dotfer comb 40. The inner terminal end portion 34 of the dofier comb assembly 30 is connected to the shaft extension 26 of the dotfer comb box, and to this end, the shaft extension 26 is provided with a bore 42 which receives the inner terminal end portion 34 of the doffer comb shaft, the comb terminal end portion being held in place by means of a compression sleeve 44 having a conical bore adapted to exert a clamping force on the projecting terminal end portion 34 of the comb shaft 32 and a nut 45. The opposite terminal end portion 36 of the doifer comb shaft is mounted for oscillatory movement in a fixed support 48 by means of a self-aligning ball bearing 50 seated on an adapter sleeve 46. By this arrangement in the normal operation of the doffer comb assembly, the comb 40 is oscillated back and forth due to the driving connections between the rocking shaft, the crank 20, crank shaft and pulley which, as noted above, is connected to the cylinder of the card.

In accordance with the present invention means are provided for counterbalancing the acceleration forces which contribute to bearing failure and more specifically a means for conserving the energy of the dotfer comb at the reversing position and reapplying it to the comb by way of additional impetus when the comb is accelerated toward the middle position. By this arrangement the high acceleration forces associated with reversal at the end positions are reduced and hence the life of the bearings in the dolfer comb box can be increased considerably from 20 to 30 times depending on the working speed. To this end in accordance with the principal embodiment of the invention illustrated in FIG. 1, a torsion rod 60 is provided which, as illustrated, extends through and is spaced from the peripheral wall of an eccentric bore 62 in the doffer comb shaft 32 and is secured at its inner end in a bore of the rock shaft by means of a press fit, and at the opposite end is fixedly secured to the support 48 by means, in the present instance of a nut 63 and a compression sleeve 64.

To obtain a balanced construction it may also be of advantage to locate the ends of the comb shaft eccentrically on the comb shaft whereby it is possible to balance the doffer comb without the necessity of applying weights, etc. externally of the comb shaft.

In the operation of apparatus of this type it may be necessary to vary the speed of oscillation of the doifer comb and this may be accomplished through the transmission connection to the dofier comb box. For example, it may be desirable to change the speed for treatment of different fibrous materials or producing different output volumes per hour. In apparatus embodying the torsion rod of the present invention, at the start of the card, the doflfer cylinder and the dotfer comb will have a proportional relation between surface speed and frequency respectively from the start enduring all of the acceleration during maximum speed and then during steady state. The torsion rod of the present invention operates to balance the acceleration forces under all of these conditions. For example, the chart in FIG. 3 shows that as the speed is increased from N1 to N3, the load increases at all positions of the doifer comb. FIG. 4 shows how the forces are reduced by means of the present invention. Curve K1 corresponds to curve N3 in FIG. 3 and curve K2 represents the counter-acting force of the torsion rod. The resulting force may be read on curve K and as is clear, there is a considerable bearing load decrease by reason of the operation of the torsion rod in accordance with the present invention.

The particular arrangement of the torsion rod produces the desired results noted above and it is noted that these results cannot be achieved in systems which bear a superficial resemblance to the present invention.

For example, in a system where the torsion rod carries a mass at both ends, if one mass is held fixed and the other is given a revolving movement, the masses Will oscillate in opposite directions back and forth when set free. The extent of oscillation depends on size of the masses and the rheostat in the torsion rod. In an arrangement of this type, the forces are not counter-balanced under all operating conditions of the dofier comb assembly.

There is shown in FIGS. 5 and 6 a doifer comb assembly incorporating another embodiment of means for reducing the high acceleration forces at the end positions of the doifer comb. In this embodiment the general arrangement of the dolfer comb box and doffer comb are similar to that described above and comprise a dolfer comb box having rotatably journalled therein a crank shaft 82 mounting at one end a pulley which is driven by a belt transmission connected by a cylinder of the card and a rock shaft 84 connected to the crank shaft by means of a crank mechanism generally designated by the numeral 86 to effect oscillating movement of the rock shaft and the doffer comb 90 connected thereto. The doifer comb 90 as illustrated is connected at one end to the rock shaft extension 84a by means of a sleeve 132 and a nut 134 and at its opposite end is rotatably journalled in a hearing assembly housed in a fixed support.

In the present instance, the outer end of the rock shaft 84 has an extension which carries a sleeve having a pair of diametrically opposed outwardly extending rigid wing members 142. The outer ends of the wing members engage between opposing coil springs 144, the coil springs as illustrated being fixed between stationary ear extensions formed integrally with the doifer comb box.

An alternate spring arrangement similar to the embodiment described above is illustrated in FIG. 7. The dofrer comb box and comb assembly are identical to that described in connection with the embodiment of FIG. 6. However, in the present instance a collar 240 is mounted on the outer extension of the rock shaft which in turn mounts a pair of diametrically opposed resilient wings 242 which, at their outer ends engage opposed restraining members 243. By this arrangement, during oscillation of the rock shaft, the leaves 242 yield and the effect is to reduce the moment at the reversing position of the comb shaft which has the effect of minimizing the deleterious forces on the bearings in the doffer comb box mounting the various actuating elements thereof.

There is illustrated in FIG. 8 still another embodiment in accordance with the present invention. The doffer comb box and dolfer comb shaft assembly are generally similar to the previously described embodiments, the dofler comb box which is generally designated by the numeral housing a rotatably mounted crank shaft which carried a pulley 314 at one end driven by a belt transmission connected to the cylinder of a card, a crank shaft journalled in bearing assemblies in the doffer comb box and a crank mechanism connecting the crank shaft to a rock shaft 328. The rock shaft 328 has a forward extension 328a having a bore therein which receives the inner terminal end portion of the doffer comb shaft 332, the opposite end of the dolfer comb shaft 332 having a terminal portion which is rotatably journalled in bearing mounted in a fixed support.

In the present instance the rock shaft has an axially extending bore 359 therein running throughout its length which communicates with the bore section in which the inner terminal end of the dotfer comb shaft is mounted to receive a torsion bar 360. The torsion bar at one end is fixedly connected to the main frame of the machine as at 365 and at its opposite end has an enlarged piston portion 361 which is press fitted in the bore in the rock shaft. The portion of the torsion bar 360 which telescopes in the bore 359 of rock shaft 328 is spaced therefrom. Accordingly, in operation as the rock shaft oscillates to impart an oscillating movement to the doffer comb assembly between opposite limit positions, the torsion bar is twisted slightly with the effect that it reduces the moment at the extreme limit positions at the doifer comb assembly which in turn reduces the harmful forces on the bearings mounting the various elements of the doifer comb box to extend their life and the life of the entire assembly considerably.

While particular embodiments of the present invention have been illustrated and described herein, it is not intended to limit the invention and changes and modifications may be made within the scope of the following claim.

We claim:

1. A dofling mechanism comprising a doffer comb box, a dofifer comb shaft, a comb mounted on said shaft, a rock shaft rotatably journalled in bearings in said doffer comb box and connected to the dofter comb shaft, actuating means in said doffer comb box for oscillating the rock shaft and doffer comb shaft and biasing means operable to provide a load on the doifer comb shaft opposing the acceleration and retardation loads whereby the net reaction on the bearings is reduced, said biasing means comprising a pair of diametrically opposed resilient wing members projecting radially from one end of said rock shaft and opposed restraining members engaging the outer terminal ends of each of said wing members.

References Cited UNITED STATES PATENTS 2,604,669 7/1952 Smith 19-106 2,827,578 3/1958 Carissimi et al 31038 FOREIGN PATENTS 1,351,572 12/1963 France.

841,869 6/ 1952 Germany. 744,786 2/ 1956 Great Britain. 477,650 l/ 1953 Italy.

DORSEY NEWTON, Primary Examiner

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