US3013606A

US3013606A - Oscillating mechanisms

Info

Publication number: US3013606A
Application number: US773991A
Authority: US
Inventors: Denis A Goddard
Original assignee: Dominion Engineering Works Ltd
Current assignee: Dominion Engineering Works Ltd
Priority date: 1958-11-14
Filing date: 1958-11-14
Publication date: 1961-12-19
Anticipated expiration: 1978-12-19

Description

Dec. 19, 1961 Filed Nov. 14, 1958 D. A. GODDARD OSCILLATING MECHANISMS 5 Sheets-Sheet 1 ODDfl/PD Dec. 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 2 Dec. 19, 1961 GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 3 "Lin i7 106 Dec. 19, 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 4 lIg lB I1g l-3l Lin \AMIIII 0110/11/ H103 QC/ I;

Dec. 19, 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 SheetsShet 5 Due/2727 .5 ::::.U 6 0001420 3,0135% Patented Dec. 19, 1961 3,013,606 (BSQHLLATENG MEQHANEMS Denis A. Qoddard, Como, Quebec, Canada, assigns! to Dominion Engineering Works Limited, Montreal, Quebee, Canada Filed Nov. 14, 1958, $01. No. 773,991 14 lClaims. (Cl. 162-355) This invention relates to a machine section supporting and oscillating mechanism which, while particularly adapted for supporting and oscillating the table roll secion or sections of a Fourdrinier type paper-making machine, may be used in other relations where it is desirable or necessary to impart oscillating movement to one or more sections of a machine.

In the present instance the invention will be described as embodied in a Fourdrinier paper machine, but, as indicated above, this is illustrative rather than limiting.

It is common practice in the paper making industry to provide oscillation at right angles to the direction of travel of a fourdririer wire, in the formation section of said wire, to assist in the paper formation" control and to endeavour to provide random distribution of the stock fibres across the face of the wire during the more liquid sta e of the formation of the paper sheet.

The papermalrer has long desired to have a range of frequencies and amplitudes of oscillation at his disposal in order that he may vary the oscillation to meet varying conditions, such as, for example, a change in the stock condition and/or differences in the desired weight or strength of the paper to be produced.

In the past the Fourdrinier type paper machines have been provided with the oscillating section or sections sup ported on vertical, laminated, plate springs. Due to the non-adjustable nature of these laminated plate springs it is not feasible to utilize to any degree the frequency amplitude range obtainable from an oscillation producing mechanism employed for the oscillation of the section or sections of th papermaking machine. The practical impossibility of setting up the conventional type of laminated spring support so that all laminates take an equal share of the load, together with corrosion, extreme stress reversals of the springs, continuous operation and a wide frequency range to which the springs cannot be matched, leads to early spring failure and frequent replacement of spring laminates. The replacement laminates of incorrect length also aggravate the support structure and frequently result in complete breakdown.

The pre ent invention proposes to overcome all of these disadvantages and inacequate qualities, and to provide an oscillating mechanism capable of a Wide range of fre quencies and amplitudes of oscillation adjustable to those of the oscillation producing mechanism. According to one embodiment of the present invention, the weight of the paper machine oscillating section or sections is taken on supporting members, struts or pivot arms while adjustable spring-rate torsion bar springs, which are adjustable as regards resonance wi h the forced frequency oscillation of said oscillation producing mechanism, serve as energy reservoirs and thus assist in reducing the amount of power required for maintaining oscillation.

A prestressed torsion bar spring is anchored at one end to a stationary portion of the Fourdrinier paper machine while the other end of the torsion bar spring is secured to one end of a strut which in turn is rotatably connected at its other end to the oscillating section. In the preferred arrangement, the said other end of a torsion bar spring is carried in flexible bush bearings secured to the stationary portion of the paper machine for rotation of the lower end of the strut. The upper end of the strut is also rotatable about an axis carried in flexible bush bearings secured to the oscillating section of the paper machine. The flexible elements of these hearings permit oscillation of the sup porting struts without recourse to rolling or sliding bearings and their attendant clearance, lubrication and other problems. Also, the damping characteristics inherent in this flexible type bearing permit the use of the torsion bar springs at resonance or near resonance which otherwise would not be desirable.

The torsion bar spring anchor may be rendered movable 'axialy of the torsion bar spring, to alter the effective length of the torsion bar spring, so that the spring rate or stiffness of the torsion bar spring may readily be adjusted for resonance with variations in the frequency and amplitude of the forced oscillation for correct functioning. In any single oscillating section, torsion bar springs are arranged on either side of the machine and are prestressed in opposition.

The superior stability of an oscillating forming section mounted on this type of prestressed pivotal support makes more practical the possibility of dividing the section into parts which enable a papermaker to graduate or oppose oscillation in any number of separate sections. Due to t is stability the need for horizontal leaf springs normally employed in the conventional Fourdriniers as a means for estraining movement in the direction of travel of the wire is eliminated.

The compact nature of this invention permits the independent mounting of the breast roll section and the table roll section if desirable. In this connection, according to another embodiment the weight of the breast roll is taken on pivotal members which comprise supporting brackets for the breast roll which are adjustable as to the amount of prestress employed but of fixed spring rate or stiffness of the torsion bar spring. Due to the small mass involved in oscillating one roll, it is not necessary to provide adjustable spring rate to torsion bar springs but a different spring-rate torsion bar spring can be, in.- serted into the mechanism if a different oscillation speed range is desired. The spring-rate of the torsion bar spring in this embodiment is chosen as the average for the speed range it is desired .to work in.

In this latter embodiment the prestressed torsion bar springs are each anchored at one end to a stationary portion of the Fourdrinier paper machine while the other end of the torsion bar spring is connected to the oscillating breast roll bearing brackets with the axis of the torsion bar spring coinciding with the axis of the said bearings. As the torsion bar spring of each breast roll bearing bracket is prestressed in opposition the stability of the mechanism during oscillation will be apparent.

From the foregoing it will .be. appreciated that a particular object of this invention is to provide a paper machine with pivotal supports for the oscillating section or sections which are connected with prestressed torsion bar springs which are adjustable as regards resonance with the frequency of an oscillation producing mechanism in order to enable a papermaker to use a wider range of oscillation to meet a variation of conditions which may be encountered during the course of manufacture.

Another object of this invention is to provide a pivotal supporting means for carrying the weight of the oscillating section or sections and torsion bar springs connected to said pivotal supporting means for motion control of same during oscillation.

Still another object is to provide a means for resiliently supporting the oscillating section of a paper machine which is capable of increasing the life of the mechanism used for producing oscillation, by reducing the force needed to maintain oscillation of said paper machine section.

A further object is to provide flexible bearings for the pivotal supporting structure which are capable of isolating the oscillating section or sections from vibrations not emanating from the oscillation producing mechanism.

A still further object is to provide an oscillating section support structure of the character described with a simple and positive locking means capable of maintaining said support structure in an upright position when required.

The above and other objects and characteristic features of this invention will be understood more readily from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of a Fourdrinier paper machine oscillating section in which one embodiment of this invention is shown.

FIG. 2 is a vertical sectional view taken along the lines 22 of FIG. 1.

FIG. 3 is a sectional view taken along the lines 33 of FIG. 1.

FIG. 4 is a plan view enlarged of a shake mechanism, showing its connection to the oscillating section of the paper machine of FIG. 1.

FIG. 5 is an enlarged elevational view, partly in section of the oscillating mechanism shown in FIGS. 1 and 2.

FIG. 6 is an end view of a bracket shown in FIG. 5.

FIG. 7 is an end view of another bracket shown in FIG. 5.

FIG. FIG. 5.

FIG. 9 is an end view of still another bracket shown in FIG. 5.

FIG. 10 is an end view, partly in section, showing the oscillating mechanism at one side of the paper machine in a partial state of assembly.

FIG. 11 is an end view similar to FIG. 10 but showing the oscillating mechanism at the other side of the paper machine.

FIG. 12 is an enlarged elevational view of the torsion bar spring anchoring means shown in FIGS. 1 and 3.

FIG. 13 is an end view of the anchoring means shown in FIG. 12.

FIG. 14 is a side elevational view showing a breast roll mounting of a paper machine according to another embodiment of this invention.

FIG. 15 is an enlarged elevational fragmentary view, partly in section, detailing the breast roll mounting shown in FIG. 14.

FIG. 16 is an end view of the breast roll mounting shown in FIGS. 14 and 15.

FIG. 17 is a view of the opposite end of the breast roll mounting shown in FIG. 16.

FIG. 18 is an elevational view of the shake mechanism connection bracket shown in FIG. 16.

Referring more particularly to FIGS. 1 to 14, a pair of laterally spaced shake rails 5 and 6 are mounted adjacent one end on separate stands 7, each being provided with a flexible pedestal 8 which permits a small degree of lateral pivoting of the shake rails 5 and 6 relative to the stand 7. The shake rails 5 and 6 are held in spaced relation by girt rails 10 which are fitted in girt 8 is an end view of the support strut shown in rail brackets 11 on the underside of the shake rails 5 and 6. The girt rails are held at each end against displacement relative to the bracket 11 by a taper key 12. A plurality of table rolls 14 are mounted over the shake rails in end bearings 15 carried by the shake rails 5 and 6.

The end of rails 5 and 6 remote from pivot stands 7 are downwardly and then outwardly offset to provide two parallel extensions 16 for the mounting of end bearing supports 17 for a breast roll 18 and the mounting of stands 19 of a forming box 20 located intermediate the breast roll 18 and the first table roll 14. The rear shake rail 6 is connected to a shake mechanism, generally indicated at 22, through the medium of a linkage 23 pivotally connected to a bracket 24 mounted at one side of shake rail 6 as indicated at 25. The shake mechanism 22 causes a lateral shaking movement of the shake rails 5 and 6 about their pivotal mounting on stands 7 which in turn imparts a shaking movement to the breast roll 18, forming box 20 table rolls 14 and the overlying portion of a Fourdrinier wire 26. The underlying portion of wire 26 is trained around tensioning and guide rolls 27 and 28 on its return from passage about a couch roll (not shown) which is located beyond the end of the shake rails remote from the breast roll.

The shake rails 5 and 6 are each connected remotely from their pivotal stands 7 to an oscillating mechanism generally indicated at 30 which is mounted on a stand 31. The oscillating mechanism 30 is connected to one end of a torsion bar spring 32 having its other end secured in an adjustable anchor bracket 33 mounted on a stand 34.

As will be seen more particularly in FIGS. 5 to 11, each shake rail of the oscillating mechanism 30 is supported by a supporting member strut or pivot arm 35 provided with an upper bore 36, into which the outer casing of a flexible bush bearing 37 is press-fitted or keyed. A pivot pin 38 is then press-fitted or keyed into the inner casing of the flexible bush bearing 37. The ends of the pin 38 on either side of arm 35 are fitted in split brackets 39 which are secured to the underside of each shake rail 5 and 6 so that the axis of pin 38 is in the longitudinal direction of the corresponding shake rail. The pins 38 are secured against rotation relative to their supporting brackets 39 by suitable means which may consist of a key or, as shown, by press fitting the two halves of the split brackets 39 about the pin by means of clamping screws 40 (see FIG. 5). The ends of the arm 35 defining the upper bore 36 are recessed at 42 to receive an 0 seal ring 43.

The strut or pivot arm 35 is also provided with a lower bore 45 through which a portion 46 adjacent one end of the torsion bar spring 32 is slidably fitted. The portion 46 of the torsion bar spring 32 and the bore 45 are provided with complementary keyways 47 and 48 (FIGS. 10 and 11) to receive a key 49. Portions 50 on either side of torsion bar spring portion 46 which are of slightly lesser diameter, are provided with flexible bush bearings 51. The bearings 51 have their inner casings keyed or press-fitted about the torsion bar spring portions 50. The outer casings of bearings 51 are fitted into the

split brackets

52 and 52a which are secured to the stand 31 by bolts or other suitable means so that the axis of torsion bar spring 32 parallels the axis of pin 38 of the corresponding shake rail. The ends of the arm 35 defining the lower bore 45 are also recessed at 53 to receive an 0 seal ring 54. Screws 55 clamp the half-sections of

brackets

52 and 52a about the bush bearings 51. The outer ends of the

brackets

52 and 52a are fitted with covers 59 and a seal ring 60.

As shown in FIGS. 12 and 13, the other end of torsion bar spring 32 is secured in an anchor bracket 33. The anchor bracket 33 is mounted on a table top 61 of stand 34 between guide rails 62 which permit the anchor bracket to be moved in the lengthwise direction of the torsion bar spring 32 so that the said anchor bracket amass e 33 which is provided with a bore 64 is adjustable along an end portion 65 of the torsion bar spring 32 which is receivable in said bore. The bore 64 and the end portion 65 of torsion bar spring 32 are provided with

complementary keyways

66 and 67 into which a key 68 is fitted. Clamp bolts 69 through guide rails 62 are loosened to permit sliding adjustment of the anchor bracket 33 and are tightened to secure the anchor bracket in its adjusted position along the length of the torsion bar spring end portion es.

in H68. and ll end views of the struts or pivot arms 35 for the shake rails 5 and 6 respectively, are shown. In these views the upper and

lower brackets

39 and 52a on the near side have been removed for the sake of clarity. By comparing FIGS. 10 or 11 with PEG. 13 it will be seen that the keyway 4'7 in the torsion bar spring portion 46 for the oscillating mechanism 30 is radially offset (FiGS. l0 and ll) with respect to the keyway 67 in the opposite end portion 65 or" the torsion bar (FIG. 13) which is slidably fitted in the bore 64 of anchor 33. When the end portion 65 or" one torsion bar spring is keyed to the corresponding anchor 33 (see FIG. 13), the oitset position of keyway 47 requires that the strut or pivot arm 35 of shake rail 5 be inwardly inclined at about 5 from the perpendicular in order that the lower sleeve 45 may be keyed to the torsion bar spring portion as, as shown in FIG. 10. Similarly, when the end portion as of the other torsion bar spring is keyed to the corresponding anchor 33 (see also FIG. 13), the offset position of keyway 47 as shown in FIG. 11 requires that the strut or pivot arm 35 of shake rail 6 be inwardly inclined at about 5 in opposite direction to the strut or pivot arm shown in FIG. 10.

In order to move the struts or pivot arms 35 to a vertical position suitable levers (not shown) are inserted in transverse openings "1% in the pivot arms 35. The

pivot arms 35 are then rotated outwardly about the axes of the torsion bar spring 32 and at the same time apply a torque to the torsion bar spring 32 which tends to bias the pivot arms 35 to swing inwardly. When the pivot arms 35 are in their vertical position (FIG. 5) a pin '72 is fitted in an opening ?3 provided in the end of pivot arm 35 adjacent bracket 52a. Bracket 52a is provided with a shoulder 74- against which the projecting portion of pin 72 bears to prevent rotation of the pivot arm 35 in response to the bias of the torsion bar spring 32. While FEGS. 5 and 9 show the shoulder to be on one side of bracket 52a which is suitable for stepping rotation of the strut or pivot arm 35' of shake rail 5 in one direction, it will. be appreciated that the shoulder of bracket 5% on pivot arm 35 of shake rail 6 will be on the reverse side for stopping rotation in the opposite direction.

When the stop pins 73; are in place the clamping screws 55 of the half sections or"

brackets

52 and 52a are tightened to bring the inner surfaces of the brackets to bear against the outer casing of the corresponding flexible bush bearings 51 to prevent relative movement between the bracket and the said outer casing and therefore movement of the pivot arms 35 on either side of the vertical position is effected through the flexible portion of the bush 51.

After the pivot arms are secured in their vertical position and the flexible bush bearings 51 are secured to the brackets 52, 52:: the shake rails 5 and 6 are secured by bolts or other suitable means to the flanges of the upper brackets 35' of the corresponding oscillating mechanism 30. With the girt rails 1h emplaced in the brackets 11, the equal biasing or" the prestressed torsion bar spring in opposite directions normally holds the struts or pivot arms 35 in vertical positions and the stop pins '72 may be removed from the openings 73 as these are only used to prevent unintended lateral movement of the shake rails. The size of that portion of each stop pin is reduced to a deg 'ee which will normally hold the pivot arms in their upri ht position but will be readily sheared oil under the action of the shake mechanism should an operator neglect to remove the pins before actuating said shake mechanism.

Each stand 31 is provided with an extension bracket 75 which supports a doctor stand 76 for a breast roll doctor 77.

In operation, the shake mechanism 22, sets up an oscillating movement to the shake rails 5 and 6 at right angles to the direction of the Fourdrinier wire. This oscillating movement is aided by the oscillating mechanism 31; located substantially adjacent one end of the shake rails which allows the rails to be moved back and forth about their pivotal mounting '8 located substantially adjacent the other end of the rails in response to the reciprocating motion of the shake mechanism 22. in this manner the stock fibres receive a lateral dispersing motion during their travel along the wire from the breast roll which assists in formation control and encourages random orientation of the fibres during the period that the stock water is draining.

The oscillating mechanism 3%} normally supports one end of the shake rails in an upright position. Due to the prestressing of the torsion bar springs 32 of each shake rail oscillating mechanism in opposite direction, the forced-frequency oscillation imparted by the shake mechanism 22 can be suitably regulated to produce a stabilized oscillation of the shake rails and related attached parts such as the breast roll and the forming box.

As will be seen, when forced movement is imparted by the shake mechanism 22 in one direction, the prestressing of one torsion bar spring is at least partially diminished while the torque is increased in the opposing torsion bar spring and thereby builds up a returning force in the second mentioned torsion bar spring which will reduce the force required to initially move the shake mechanism 22 at the beginning of its return stroke.

During the oscillating movement of the oscillating mechanism iii the flexible bush bearings 37 and 51 are under shear from either side of the vertical position and have a damping eifect, permitting oscillation at resonant frequency with the spring mass and combination. This reduces any shock which might otherwise be imparted to the oscillating mechanism from the shake mechanism. These flexible bush bearings also absorb vibrations from other sources which might otherwise be imparted to the shake rails and interfere with the proper functioning of the shake mechanism.

In order that there will be complete harmony of resonance with the stroke of the shake mechanism, the torsion bar spring 32 is adjustable as to length to vary the frequency by moving the anchor 33 longitudinally of the torsion bar spring between the guide rails 62. The frequence may also be varied by substituting a torsion bar spring of a greater or lesser cross-section. When the torsion bar springs are in resonance with the shake mechanism the amount of power required or the shake mechanism is greatly reduced, being only that necessary to maintain motion. The length of the torsion bar spring may be varied, if the length and rate of shake mechanism is altered, to adjust the torsion bar springs to resonance with the new forced-frequency oscillation of the shake rails 5 and 6. The torsional prestress is applied to each torsion bar spring in opposite directions suffciently to ensure that movement of the oscillating mecl2- anism, does not completely unwind either torsion bar spring or set up stress reversals in either torsion bar spring and thereby cause fatigue failure in the torsion bar springs. This is accomplished by applying a sufficient prestress to each torsion bar spring so that the complete unwinding of one torsion bar spring requires a greater movement in one direction than the distance afforded by the maximum stroke of the shake mechanism.

Although FIG. 1 of the drawings shows only a single pair of oscillating mechanisms with torsion bar springs. The invention also contemplates the use of several similar oscillating mechanisms located at different stations along the length of a paper machine in the forming section thereof.

The invention also contemplates the separate mounting of a breast roll for independent oscillation by a shake mechanism of the breast roll. In this manner the breast roll and the shake rails with the table rolls thereon may be oscillated at different frequencies.

FIGS. 14 to 18 show a modification in which the breast roll 30 of a Fourdrinier paper machine is separately mounted on laterally spaced stands 81 relative to the shake rails 82 and table rolls 83. The breast roll 80 is mounted between laterally spaced bearing brackets 84- each of which comprises upper and lower sections 84:: and 84b hinged at 85 to permit insertion of a spherical breast roll bearing 86 therebetween, and are secured by a clamping bolt 87 when fitted about said breast roll bearing. Each breast roll bearing bracket 04 has a longitudinal bore 88 through the base through which a supporting tube 89 is slidably fitted. The ends of the tube 39 adjacent the outer ends of the breast roll bearing bracket bore 88 are reduced, as indicated at 90, to provide shoulders 91 against which the inner ends of flexible bush bearings 92 are abutted when fitted about the reduced portions 90. The flexible bush bearings are fitted in split bearing

support brackets

93 and 93a. The split brackets 93 and 9311 are clamped against the outer casing of bush bearing 92 by clamping screws 93x. Said

brackets

93 and 93a are suitably secured to the table of stand 31. The right hand end of the reduced portion 90 of tube 89 is further reduced as indicated at 94 to provide a shoulder 95. Tube portion 94 is threaded adjacent the shoulder 95 to receive a clamping nut 96 which bears against the shoulder 95 and the adjacent end of the inner casing of bush bearing 92 to prevent movement of the casing relative to the tube.

A torsion bar spring 100 having thickened ends 10 1 and 102 is fitted through the tube 89 with its end 101 secured against rotation relative to the tube by means of a securing pin 103 which extends through aligned pin openings in the tube end portion 94 and said torsion bar spring end 101. The tube 89 is then secured to the base of the breast roll bearing bracket section 84b by pins 104 to prevent rotation of the tube 89 in the bore 88 of bracket section 84b. The reduced portion of the torsion bar spring 100 passes freely through the tube 39 and the bearing support bracket 93 and its thickened end 102 is mounted in a split anchoring bracket 105 having its base suitably secured to the table of stand 81. The thickened portion 102 of torsion bar spring 100 has a marginal extension 106 which projects beyond the outer end of anchoring bracket 105. A lever 107 has one end fitted about extension 106 and secured thereto by a retaining pin 108. The other end of lever 107 is provided with a threaded opening through which a bolt 109 is adjustably threaded so that the lower end thereof is engageable with the base 110 of anchoring bracket 105.

In assembling the breast roll bearing brackets 84 they are arranged between the

support bearings

93 and 93a with a slight inward incline, preferably about from the vertical position. After the

pins

103 and 108 have been secured through the opposite thickened ends of the torsion bar spring to secure said ends to portion 94 of tube 89 and to lever 107 respectively against relative rotation therebetween, the bolt 109 is adjusted vertically to engage the base 110 of bracket 105 so as to prevent further downward movement of the lever 107. The breast roll hearing brackets 84 are then rotated about their longitudinal axes extending through the bore 88 to a vertical position. As one end of the torsion bar spring is spring anchored to the lever 107 which is held against rotation by bolt 109, and as the other end of the torsion bar spring is secured to the end portion 94 of tube 89 the outward rotation of the brackets 84 applies a torsional prestress to the torsion bar. When the thus prestressed pivotal mechanisms of the breast roll brackets 84 are in their vertical positions pins 112 are inserted in end openings of the bracket sections 84b and are adapted to bear against stops 114 carried by the supporting brackets 93a. The pins .112 are of a material and thickness which is adequate to hold the breast roll bearing brackets 84 in their vertical positions against the normal bias of the torsion bar spring, but which will rupture if additional external force be applied, such as by the shake mechanism attached thereto, and the operator has neglected to remove the pins before actuating the shake mechanism. Holes 115 may also be provided in the transverse direction of the brackets 84 so that a lever (not shown) may be inserted therethrough to enable rotation of the brackets 84 about their longitudinal axes.

When the brackets 84 are secured in their vertical positions the upper sections 8411 are swung about their pivots to a position which enables the mounting of the spherical bearings 36 on the journals of the breast roll 80. The sections 34a are then clamped about bearings 86 by bolt 87. The right hand breast roll bearing bracket 84. as shown in FIG. 16 is provided with an extension 116 on the outer side thereof upon which shake mechanism attaching bracket 117 is mounted and secured in place by a key 118 and bolts 119. The upper end of bracket 117 is pivotally connected at 120 to links 121 arranged on either side of said brackets. The links 121 form a part of a shake mechanism similar to that shown in FIG. 4.

In operation, a shake mechanism of the type shown in FIG. 4, which is linked to the shake mechanism attaching bracket 117 carried by one of the breast roll bearing brackets 84, oscillates the breast roll bearing brackets about their longitudinal pivotal axes extending through the bores 88 of the base portions of said brackets against the opposed biasing of the torsion bar springs in the same manner as described in connection with the pivoting of the strut 35 of the above oscillating mechanisms 30 against the biasing of their torsion bar springs 32. The flexible bush bearings 92 have the same dampening and cushioning efiect between the tube 39 and the

support brackets

93 and 93a as that previously described in relation to the bearings 51,

brackets

52 and 52a and the torsion bar spring end portions 50.

Here, the prestressing of the torsion bar spring 100 is adjustable. This prestressing adjustment is effected by vertical movement of the bolt 109 in the free end of lever 107 so that there will be an equal stress on each torsion bar spring 100 in opposite directions. Prestressing of the torsion bar spring 100 in opposite directions should be sufiicient to ensure that the unwinding torsion bar spring 100 will not reach a point of zero or reverse stress at the maximum stroke of the shake mechanism in order that the torsion bar spring will not be subjected to reverse stresses, and fatigue failure. In this particular embodiment the loading for one roll is so light that an adjustable spring rate torsion bar spring has not been provided, the size being chosen to suit the average oscillation rate. Large changes in speed may be accommodated by fitting a different length torsion bar spring.

What I claim is:

1. In an oscillating mechanism, a pair of laterally spaced supporting members pivotally mounted at their lower ends to rotate about separate parallel axes, said supporting members each having an upper portion connected to opposite sides of a member to be oscillated to pivot about axes parallel with the pivotal axes of the lower ends of said supporting members, and means normally applying a turning moment to each of said supporting members tending to simultaneously force pivotal movement of said supporting members about their lower axes in opposed directions so that oscillating movement of said mechanism in one direction progressively diminishes the turning moment in one of said supporting members and progressively increases the turning moment in the other of said supporting members, characterized in that the maximum increased turning moment of said last mentioned supporting member is utilized as an impelling force during the initial oscillating movement in the opposite direction.

2. In an oscillating mechanism, a pair of laterally spaced supporting members, each pivotally connected at its lower end to a fixed base so that the supporting memhere can turn about separate parallel axes, a member to be oscillated supported by said supporting members, said member to be oscillated being connected to said supporting members topivot about axes spaced from and parallel with the pivotal axes at the lower ends of said supporting members, and a torsion bar spring axially aligned with the lower pivotal axis of each supporting member, each torsion bar spring having one end secured to a corresponding supporting member and means for anchoring a portion of said torsion bar spring remote from its point of securing to said supporting member to resist rotary move ment of the anchored portion of said torsion bar spring, said torsion bar springs being prestressed to apply a force tending to pivot each of said supporting members about its lower axis in opposed directions so that oscillating movement in any one direction reduces the pivoting force of one torsion bar spring and increases the pivoting force of the other torsion bar spring characterized in that the said increased force is utilized an initial impelling force to the corresponding supporting member during its initial oscillating movement in the opposite direction.

3. An oscillating mechanism as set forth in claim 2, in which the opposed prestressing of said torsion bar springs applies forces urging said supporting members to pivot toward each other.

4. An oscillating mechanism as set forth in claim 2, in which the torsion bar springs are prestressed for an amount sntiicient to ensure that they will not be subjected to reverse stresses during said oscillating movement.

5. An oscillating mechanism as set forth in claim 2, in which said anchoring means is movable along the length of the torsion bar spring to alter the eifective length of the bar so that the spring rate or stiffness of the torsion bar spring may be adjusted for resonance with variations in the frequency and amplitudes of oscillation.

6. In a Fourdrinier paper machine a table roll section including a pair of laterally spaced shake rails sup porting a plurality of table rolls upon which a paper forming wire moves in the longitudinal direction of the shake rails, and oscillating means supporting said shake rails, said oscillating means comprising a pair of laterally spaced supporting membcrs, each pivotally connected at its lower end to a fixed base so that the supporting member can turn about a separate parallel axis, each supporting member being also pivotally connected at its upper end to one of said shake rails for vertical support of said rail and to rotate about a separate axis spaced from and parallel to the said axis at the lower end of said supporting member, and a pair of torsion bar springs, each torsion bar spring having one end secured to a corresponding supporting member in axial alignment with the lower pivotal axis of said supporting member and anchoring means securing a portion of said torsion bar spring located remotely from the end of said torsion bar sprin secured to said supporting member to resist turning movement the anchored portion of said torsion bar spring, said torsion bar springs being prestressed intermediate the anchored portion and the end secured to the supporting member to apply a force tending to pivot said supporting members about their lower axes in opposed directions so that application of oscillating movement in any one direction reduces the pivoting force of one torsion bar spring and increases the pivoting force of the other torsion bar spring characterized in that the said increased pivoting force is utilized as an initial impelling force to the corresponding sup- '19 porting member during its initial oscillating movement in the opposite direction.

7. A Fourdrinier paper machine as set forth in claim 6, including a shake mechanism connected to one of said shake rails to produce oscillation substantially at'ri'ght angles to the line of travel of said wire.

8. A Fourdrinier paper machine as set forth in claim 6, including a breast roll mounted on said shake rails adjacent one end thereof to be oscillated therewith.

9. A Fourdrinier paper machine as set'forth in claim 6, in which said oscillating means supports said shake rails adjacent one end thereof and includes means separately supporting said shake rails adjacent their opposite ends for pivotal movement about vertical axes.

10. A Fourdinier paper machine as set forth in claim 6, in which said anchoring means comprises an anchor bracket provided with a bore in which a portion of the torsion bar spring is slidably fitted, means engageable between the torsion bar spring and the anchor bracket to prevent rotation of the bar relative to the bracket, and a fixed stand provided with guide rails for sliding support of said anchor bracket to permit adjustment of said anchor bracket along the length of said torsion bar spring to alter the efiective length of the torsion bar spring so that the spring rate or stiffness of said torsion bar spring may be adjusted for resonance with variations in the frequency and amplitudes of oscillation.

11. A Fourdrinier paper machine as set forth in claim 6. in which the lower end of said supporting member is provided with a bore and is positioned between a pair of brackets secured to a fixed base and in which said torsion bar spring extends through bores in said brackets axially aligned with the bore in the lower end of said supporting member, means securing said torsion bar spring in the bore of said supporting member to prevent relative rotary movement between said torsion bar spring and said supporting member and flexible bush bearings mounted in the bores of said brackets, said bearings having their inner casings secured about the torsion bar spring and their outer casings secured to the surface of the bracket bores whereby oscillation of said supporting member is cushioned by the flexible portion between the inner and outer casings of said flexible bush bearings.

12. A Fourdrinier paper machine as set forth in claim 6, in which the upper end of one of said brackets is provided with a stop member, and a pin receivable in an end opening in said supporting member and engageable with said stop member to retain said supporting member in an upright position against the biasing force of the torsion bar spring when the mechanism is not oscillating.

13. A Fourdrinier paper machine as set forth in claim 6, in which the upper end of each supporting member is provided with a bore and is positioned between a pair of brackets secured to the under side of a corresponding shake rail, said brackets being provided with bores axially aligned with the bore in the upper end of the supporting member, a pin extending through the bores in said brackets and in said supporting member and having its axis in spaced parallel relation to the lower pivotal axis of said supporting member, means securing said pin to said brackets to resist relative rotation therebetween and a flexible bush bearing having its inner casing fitted about an intermediate portion of said pin to resist relative rotation between the said inner casing and the pin and having its outer casing secured in the bore in each end of said breast roll to support said breast roll by its bearings for rotary and pivotal movement relative to said breast roll brackets, said breast roll brackets having their lower ends mounted on fixed stands to pivot about spaced, horizontal axes, and a torsion bar spring axially aligned with the lower pivotal axis of each breast roll supporting bracket and having one end secured to said breast roll bracket and the other end secured to an anchoring means mounted on said fixed stand, the intermediate portion of said torsion bar springs being prestressed in opposition to apply forces urging said breast roll supporting brackets to pivot towards each other, characterized in that oscillation of said breast roll in any one direction reduces the pivoting force of one torsion bar spring and increases the pivoting force of the 12 other torsion bar spring whereby the increased pivoting force is utilized as an initial impelling force to the corresponding breast roll supporting bracket during its initial stage of oscillating movement in the opposite direc tron.

References Cited in the filo of this patent UNITED STATES PATENTS Re. 17,381 Aldrich July 30, 1929 1,629,087 Aldrich May 17, 1927 1,917,287 Aldrich et al. July 11, 1933 2,821,292 Spurlin Jan. 28, 1958 FOREIGN PATENTS 681,896 Germany Oct. 4, 1939