US3232828A - Variable stroke shaker mechanism for paper making machines - Google Patents

Description

1, 1966 LOUIS-MARIE OUELLET 3,

VARIABLE STROKE SHAKER MECHANISM FOR PAPER MAKING MACHINES Filed July 15, 1965 3 Sheets-Sheet 1 INVENTOR L-M. OUELLET A TTORNE YS 1956 LOUISMARIE OUELLET 3,232,828

VARIABLE STROKE SHAKER MECHANISM FOR PAPER MAKING MACHINES 3 Sheets-Sheet 2 Filed July 15. 1963 fi INVENTOR L-M. OUELLET A TTORNEY 1, 1966 LOUIS-MARIE OUELLET 3,

VARIABLE STROKE SHAKER MECHANISM FOR PAPER MAKING MACHINES Filed July 15, 1963 3 Sheets-Sheet 3 lllll INVENTOR L-M. OUELLET A TTORNEYS United States Patent Ofiice 3,232,828 Patented Feb. 1, 1966 3,232,828 VARIABLE STROKE SHAKER MECHANISM FOR PAPER MAKING MACHINES Louis-Marie Ouellet, Chateauguay Centre, Quebec, Canada, assignor to Dominion Engineering Works Limited, Montreal, Quebec, Canada Filed July 15, 1963, Ser. No. 295,141 Claims priority, application Canada, May 27, 1963, 876,599 8 Claims. (Cl. 162355) This invention relates to paper making machine fourdriniers and particularly to an improved mechanism for imparting a shaking motion, of variable stroke amplitude, to the drainage screen of a fourdrinier.

It will also be understood that the principle of this invention can be applied to any situation where it is required to convert a rotary input into a reciprocating output;

In the manufacture of certain grades of paper the fourdrinier table, around which the fourdrinier drainage screen is draped, must be shaken in the plane of the screen at right angles to its direction of travel.

In fourdriniers of this type, the fourdrinier table is pivotally mounted to permit oscillation or shaking motion at right angles to the direction of travel of the screen and is normally centered by spring means such that the bias towards null position is proportional to the displacement. Therefore, the table tends to oscillate with simple harmonic motion.

Thus, any mechanism which is used to impart a shaking motion to a fourdrinier table should, for minimum stress and wear, have the characteristic of simple harmonic motion.

It is also desirable that the shaking mechanism be provided with variable stroke amplitude control and that the output characteristic is simple harmonic over the range of amplitude control from zero to maximum.

A well known mechanism, which is used to impart a shaking motion to fourdrinier tables, employs an eccentric crank of fixed throw which imparts reciprocating motion to the output shaft by way of an adjustable toggle linkage.

One of the disadvantages of this well known mechanism is that at full stroke the deviation from simple harmonic motion is considerable.

Another disadvantage is that it is impossible to run the mechanism at zero stroke.

Still another disadvantage is that when at or near minimum stroke setting the output frequency, for a given input speed, is doubled.

These kinematic defects result in early structural and mechanical failure of the shaking mechanism and/ or the fourdrinier table and the service life of the assembly is thus very unsatisfactory. These inherent kinematic defects cannot be corrected by increasing component strength for, strengthening the shaking mechanism causes the table structure to fail and strengthening the table structure causes the shaking mechanism to fail.

The disadvantages inherent in the aforementioned well known mechanism are overcome in the present invention by the provision of an improved mechanism which converts uniform rotary motion into simple harmonic reciprocating motion of controllable stroke amplitude. This is achieved by the provision of a hollow input shaft rotatably journalled in the shaker casing and an output shaft coaxially mounted to reciprocate in said hollow input shaft. Stroke regulating means interconnects the input and output shafts such that rotation of the input shaft imparts reciprocating motion to said output shaft.

The stroke regulating means includes a secondary shaft rotatably journalled in a secondary housing which is pivotally mounted in the shaker casing to adjustably position the secondary shaft in positions of angular misalignment with the input shaft. The secondary shaft is coupled to the input shaft by means of a universal joint, the transverse centre line of which lies on a line through the pivotal axes of the secondary housing, thus the shafts will rotate together when they are axially aligned and also when their axes are angularly misaligned. An arm extending laterally from the output shaft through a slot in the input shaft is operatively connected to the secondary shaft through a ball joint linkage.

Thus, rotation of the input shaft when the input and secondary shafts are angularly misaligned, will result in reciprocation of the output shaft, from zero stroke when the input and secondary shafts are axially aligned to finite stroke when the input and secondary shafts are angularly misaligned. The opera ing principle of this invention can be considered as analogous to the basic principle of the adjustable angle swash-plate mechanism by substituting for the swash-plate two shafts coupled together by a universal joint.

It is, therefore, the main object of this invention to provide a mechanism which will impart simple harmonic reciprocating motion to a fourdrinicr table.

Another object of this invention is to provide a mechanism which will impart simple harmonic reciprocating motion, with variable stroke amplitude control, to a fourdrinier table.

Another object of this invention is to provide a shaking mechanism, the output characteristic of which is simple harmonic, over the range of stroke amplitude con trol from zero amplitude to maximum amplitude.

Another object of this invention is to provide a fourdrinier table shaking mechanism in which wear and stress is kept to a minimum.

Another object of this invention is to provide a mechanism, for imparting shaking motion to a fourdrinier table, in which the stroke amplitude can be varied during operation.

A further object of this invention is to provide a fourdrinier table shaking mechanism which is of simple yet robust construction, is of compact design and is relatively inexpensive, as compared with shaking mechanisms of the well known type.

These and other objects of this invention will be apparent by reference to the following detailed specification and figures in which:

FIG. 1 is a side view of a shaking mechanism embodying the features of this invention.

FIG. 2 is a plan view of a shaking mechanism embodying the features of this invention.

FIG. 3 is a sectional view, to an enlarged scale, taken on 3-3 in FIG. 1 and showing details of the invention.

FIG. 4 is a sectional view, to an enlarged scale, taken on 4-4 in FIG. 2 and showing further details of this invention.

FIG. 5 is a view to a further enlarged scale, taken on 55 in FIG. 4.

To obtain simple harmonic motion from the reciprocating output of the improved mechanism of the present invention, the universal joint used must be of the constant velocity type. However, when this improved mechanism is applied to shake a paper making machine fourdrinier table the range of shaft angular misaligning description of the preferred execution of this inven tion a Hookes joint type universal joint is shown incorporated into the mechanism for simplicity.

With reference now to the figures, input shaft 11 is rotatablyjournalled in bearings 12 located in upper half casing 13 and lower half casing 14. End cap 15 closes the open ends of upper and lower half casings 13 and 14 respectively and seal 16 seals the bore in end cap 15 through which input shaft 11 passes. Input pulley 17 is attached to the outer end of input shaft 11 and is driven by a driving motor (not shown) to provide the required input rotation. Output shaft 18 is coaxially mounted to reciprocate in bearings 19 positioned in bore 20 in input shaft 11. Packing gland 21 retains shaft packing 22 to effectively seal bore 20.

Secondary shaft 23 is rotatably journalled in bearings 24 in secondary housing 25. Pivot arms 26 extend outwardly from secondary housing 25 with trunnions 27 extending outwardly from pivot arms 26 and transverse to secondary shaft 23. Trunnions 27 are pivotally mounted in bearings 28, positioned in upper and lower half casings 13 and 14 respectively.

The inner end of input shaft 11 is coupled to secondary shaft 23 by universal joint 29, the transverse centre line of which is arranged to lie on a line through the pivotal axes of trunnions 27. Thus, input and second- .ary shafts 11 and 23 respectively will rotate together when they are axially aligned and also when their axes are angularly misaligned, as shown in FIG. 4.

Output arm 30 extends laterally from the inner end of output shaft 18, through a slot 31 in input shaft 11 and secondary arm 32 extends laterally from the inner end of secondary shaft 23. Slot 31 in input shaft 11 is dimensioned to locate output arm 30 such that output arm 30 can move axially in slot 31 but with output shaft 18 prevented from rotating relative to input shaft 11.

Output and secondary arms 30 and 32 respectively are operatively connected by link 33 and ball joints 34. Reference again to FIG. 4 shows secondary shaft 23 angularly misaligned with input shaft 11 by an angle 35. It will therefore be seen that rotation of input shaft 11 produces a corresponding rotation of angularly misaligned secondary shaft 23, ball joint 34, of secondary arm 32, being axially displaced when input shaft 11 is rotated 180 to the lower vertical position shown in broken line at 34a. This axial displacement is trans ferred, through link 33, to output arm 30, as shown at 36.

Thus, when the axes of input and secondary shafts 11 and 23 respectively are angularly misaligned, as at 35, rotation of input shaft 11 will result in reciprocation of output shaft 18 by the amount shown at 36.

The axial displacement, or stroke, 36 will vary from a predetermined maximum amplitude, corresponding with the predetermined maximum angle of misalignment between shafts 11 and 23, to zero stroke, when shafts 11 and 23 are axially aligned.

Adjustment of angle 35, corresponding to adjustment of stroke amplitude, is accomplished by means of the adjusting mechanism shown generally at 37.

Adjusting mechanism 37 includes an adjusting screw 38 having a head end 39 which is slotted to receive pivot pin 40. Pivot pin 40 is positioned through lugs 41 on secondary housing end cap 42. The other end of adjusting screw 38 is threaded to engage in adjusting nut 43. Adjusting nut 43 has a reduced diameter plain portion which is rotatably positioned in bore 44 in upper half casing 13 and a further reduced diameter threaded portion which engages in lock nut 45. Lock nut 45 is adjusted to provide free rotation of adjusting nut 43 in bore 44. Thus, rotation of adjusting nut 43 will result in the raising or lowering of the outer end of secondary housing 25, thus respectively increasing or decreasing angle 35 according to the direction of rotation.

The outer end of output shaft 18 is connected to shaker shaft 46 by means of a two-way thrust bearing 47, whereby reciprocation may be transmitted to shaker shaft 46 from reciprocating and rotating output shaft 18, without rotation of shaker shaft 46.

Shaker shaft 46 is directly connected to the fourdrinier shake rail 48.

In the operation of this invention, input rotation provided through input pulley 17 will result in non-rotating reciprocation of shaker shaft 46, of amplitude predetermined by the angular positioning of secondary shaft 23 by means of the adjusting mechanism 37.

Shaking mechanisms according to this invention can be operated in pairs by means of a simple worm and screw interconnection between each adjusting mechanism 3'7, with each shaking mechanism being positively driven. Differential stroke amplitudes can be obtained 'by use of suitable worm and screw ratios and corresponding drive ratios. i

This invention, therefore, provides a shaking mechanism in which modulated stroke amplitude control is obtained from zero stroke, to maximum stroke, with no double frequency output in any part of the range of stroke adjustment. When a constant velocity type universal joint is used in the mechanism, true simple harmonic motion output is obtained throughout the range of stroke adjustment, but where a small deviation from mathematically exact simple harmonic motion can be tolerated, then a less costly Hookes joint type universal joint can be substituted for the constant Velocity type universal joint.

What I claim is:

1. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing laterally to either side of a central position, a rotary hollow input shaft mounted to rotate about a fixed longitudinal axis, an output shaft mounted to reciprocate within'said input shaft and to rotate therewith, said output shaft having an output arm extending laterally therefrom and projecting through slot means in said hollow input shaft, adjustable motion transmitting means interconnecting said input shaft and said output arm for imparting a rotating and reciprocating motion of adjustable stroke to said output shaft in response to rotation of said input shaft, and means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

2. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing laterally to either side of a central position, rotary input shaft means, an output shaft mounted for rotary and reciprocating movement, motion transmitting means interconnecting said input shaft means and said output shaft for imparting a rotating and reciprocating motion to said output shaft in response to rotation of said input shaft means, said motion transmitting means including a secondary shaft operatively connected to said input shaft means to rotate therewith and operatively connected to said output shaft to impart said rotating and reciprocating motion thereto, and means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

3. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing laterally to either side of a central position, a rotary input shaft, an output shaft mounted for rotary and reciprocating motion, said output shaft having an output arm extending laterally therefrom, adjustable motion transmitting means interconnecting said input shaft and said output arm for imparting a rotating andreciprocating motion of adjustable stroke to said output shaft in response to rotation of said input shaft, said motion transmitting means including a secondary shaft operatively connected to said input shaft and mounted to rotate therewith, a secondary arm extending laterally from said secondary shaft, and link means operatively connecting said output and secondary arms, said secondary shaft adapted to rotate about an axis adjustable from a position of axial alignment with said output shaft to a position of angular misalignment with said output shaft to provide said adjustable stroke of said output shaft, and means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

4. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing laterally to either side of a central position, a rotary hollow input shaft mounted to rotate about a fixed longitudinal axis, an output shaft mounted to reciprocate within said input shaft and to rotate therewith, motion transmitting means interconnecting said input shaft and said output shaft for imparting a rotating and reciprocating motion to said output shaft in response to rotation of said input shaft, said motion transmitting means including a secondary shaft operatively connected to said input shaft to rotate therewith and operatively connected to said output shaft to impart said rotating and reciprocating motion thereto, and means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

5. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing laterally to either side of a central position, a rotary hollow input shaft mounted to rotate about a fixed longitudinal axis, an output shaft mounted to reciprocate within said input shaft and to rotate therewith, said output shaft having an output arm extending laterally therefrom and projecting through slot means in said hollow input shaft, adjustable motion transmitting means interconnecting said input shaft and said output arm for imparting a rotating and reciprocating motion of adjustable stroke to said output shaft in response to rotation of said input shaft, said motion transmitting means including a secondary shaft operatively connected to said input shaft and mounted to rotate therewith, a secondary arm extending laterally from said secondary shaft, and link means operatively connecting said output and secondary arms, said secondary shaft adapted to rotate about an axis adjustable from a position of axial alignment with said output shaft to a position of angular misalignment with said output shaft to provide said adjustable stroke of said output shaft, and means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

6. A shaker mechanism for fourdrinier paper making machines including a shake rail mounted to swing lateral- 13 to either side of a central position, a casing for said shaker mechanism, a rotary hollow input shaft mounted in said casing to rotate about a fixed longitudinal axis, an output shaft coaxially mounted to reciprocate within said input shaft and to rotate therewith, said output shaft having an output arm extending laterally therefrom and projecting through slot means in said hollow input shaft, adjustable motion transmitting means interconnecting said input shaft and said output arm for imparting a rotating and reciprocating motion of adjustable stroke to said output shaft in response to rotation of said input shaft, said motion transmitting means including a secondary shaft operatively connected to said input shaft and mounted to rotate therewith, a secondary arm extending laterally from said secondary shaft, link means operatively connecting said output and secondary arms, said secondary shaft rotatably mounted in secondary housing means, said secondary housing means pivotally mounted in said casing for adjustment of said secondary shaft from a position axially aligned with said output shaft to a position of angular misalignment with said output shaft to provide said adjustable stroke of said output shaft, said secondary housing means including a body portion having two arm members extending outwardly therefrom, said secondary shaft being rotatably journalled in said body portion, said secondary housing means being pivotally mounted on trunnion portions at the outer ends of said arm members and journalled in said casing, the axes of said trunnion portions adapted to lie on the transverse centre line of the operative connection between said input and secondary shafts, and thrust bearing means connecting said output shaft to said shake rail to impart swinging motion to said shake rail on either side of said central position in accordance with the reciprocating stroke of said output shaft.

'7. A shaker mechanism as set forth in claim 6 in which the operative connection between said input and secondary shafts comprises a universal joint.

8. A shaker mechanism as set forth in claim 6 including adjusting screw and nut means connected between said secondary housing means and said casing for adjusting the pivotal position of said secondary housing within said casing and thus the angular position of said secondary shaft relative to said output shaft.

References Cited by the Examiner UNITED STATES PATENTS 1,694,834 12/ 1928 Sinclair 74-22 1,917,287 1/1933 Aldrich et al. 162355 2,436,492 2/1948 Shepard 7422 X 2,892,352 6/1959 Saalfrank 7422 X DONALL H. SYLVESTER, Primary Examiner.

BROUGHTON G. DURHAM, Examiner.

JOHN H. NEWSOME, Assistant Examiner.

Claims (1)

1. 2. A SHAKER MECHANISM FOR FOURDRINIER PAPER MAKING MACHINES INCLUDING A SHAKE RAIL MOUNTED TO SWING LATERALLY TO EITHER SIDE OF A CENTRAL POSITION, ROTARY INPUT SHAFT MEANS, AN OUTPUT SHAFT MOUNTED FOR ROTARY AND RECIPROCATING MOVEMENT, MOTION TRANSMITTING MEANS INTERCONNECTING SAID INPUT SHAFT MEANS AND SAID OUTPUT SHAFT FOR IMPARTING A ROTATING AND RECIPROCATING MOTION TO SAID OUTPUT SHAFT IN RESPONSE TO ROTATION OF SAID INPUT SHAFT MEANS, SAID MOTION TRANSMITTING MEANS INCLUDING A SECONDARY SHAFT OPERATIVELY CONNECTED TO SAID INPUT SHAFT MEANS TO ROTATE THEREWITH AND OPERATIVELY CONNECTED TO SAID OUTPUT SHAFT TO IMPART AND ROTATING AND RECIPROCATING MOTION THERETO, AND MEANS CONNECTING SAID OUTPUT SHAFT TO SAID SHAKE RAIL TO IMPART SWINGING MOTION TO SAID SHAKE RAIL ON EITHER SIDE OF SAID CENTRAL POSITION IN ACCORDANCE WITH THE RECIPROCATING STROKE OF SAID OUTPUT SHAFT.

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