US2176431A - Loose-belt drive for paper making machines - Google Patents

Description

LOOS E -BELT DRIVE FOR PAPER MAKING MACHINES Filed Jan. 11, 1937 3 Sheets-Sheet 1 INVENTOR B.A.MALKIN ATTORNEY Oct. 17, 1939. MALKIN 2,176,431

LOOSE-BELT DRIVE FOR PAPER MAKING MACHINES Filed Jan. 11, 1937 3 Sheets-Sheet 2 INWN TOR BERNARD.A.MALKI N ATTORNEY Oct. 17, 1939. B. A. MALKIN LOOSE-BELT DRIVE FOR PAPER MAKING MACHINES Filed Jan. 11, 1937 3 Sheets-Sheet 3 I NVEN To B BERNARDJ\.MALKI N AT TORN EY Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE LOOSE-BELT DRIVE FOR PAPER MAKING MACHINES Application January 11, 1937, Serial No. 120,032

14 Claims.

This invention relates to improvements in loose belt drives for paper making machines.

With the loose belt drives now in use for operating the sections of a paper making machine it is essential that the axes of the driving and driven pulleys over which the loose driving belt is trained be in vertical alignment and that the lower pulley, which constitutes the driving pulley, be smaller than the upper or driven pulley to ensure that the belt will hang free of contact with the driving pulley when the belt is in its relaxed or non-driving condition. Since it is not always convenient or desirable to conform to these requirements the present invention has been designed to provide an improved form of loose belt drive which does not require vertical alignment of the pulley axes nor the use of a driving pulley thatis smaller than the driven pulley. To this end the present invention comprises, as one of its principal features, the provision of means whereby the relaxed belt may be held clear of the lower driving pulley when it is desired to use a driving pulley larger than the driven pulley or to install the pulleys so that their axes are out of vertical alignment.

Certain sections of a paper making machine require a very high starting torque. In the case of the dryer section, for example, the starting torque required is four to live times greater than the normal running torque. Consequently, the-loose drive belts now used for controlling the starting and stopping of a paper making machine are designed so that the initial operation of the belt tightening arrangement provides suflicient tension in the drive belt to take care of the high starting torque. If this tension, which is greatly in excess of that required for normal running purposes, is maintained after the starting period is over the belt is subjected 0 to excessive wear which requires either frequent renewals of the belt or the use of a heavier belt than would otherwise be necessary. With the belt tightening arrangements now in use there is no effective provision for conveniently 45 regulating the belt tension to suit both the starting and running conditions. With this in mind another feature of the present invention consists in the provision of simple and efiicient means whereby the running tension of the belt may be 50 closely regulated in accordance with the running torque of the paper machine sections and, for

starting purposes, may be-increased by the application of additional tension which may be instantly relieved once the starting period is over.

The foregoing and other characteristic features (C1. i l-242.7)

and advantages of this invention will be more readily understood from the following detailed description taken in connection with the accompanying drawings, in which- Fig. 1 is a diagrammatic view of a conven- 5 tional loose belt drive now employed for controlling the starting and stopping of a paper making machine.

Figs. 2, 3 and 4 are views similar to Fig. 1 but showing different modifications of the im- 10 proved loose belt drive provided in accordance with this invention.

Fig. 5 is a side elevation of a loose belt drive installation embodying my improved means for regulating the running and starting tension of l the drive belt.

Fig. 6 is a front elevation of a portion of the assemblyappearing in Fig. 5.

Fig. 7 is a longitudinal sectional view of a cylinder and piston device forming part of the as- 20 sembly appearing in Fig. 5.

Fig. 8 is a diagram showing a slight modification of the pressure applying means appearing in Fig. 5.

Figs. 9, 10 and 11 are detail sectional views 25 showing the different operating positions of a control valve forming part of the modified arrangement illustrated in Fig. 8.

In Fig. 1, I have shown a conventional type of loose belt drive employed for starting and stopping the sections of a paper making machine. The loose drive belt 5 is trained around a lower driving pulley 6 and an upper driven pulley l which are installed so that their axes or shaft centers are in vertical alignment. With 35 this conventional arrangement it is necessary that the lower pulley be smaller than the upper pulley so that, in the relaxed or non-driving condition represented by dotted lines X, the drive belt will be suspended from the upper pulley entirely clear of contact with the lower pulley. The tensioning of belt 5 to transmit power from the drive to the driven pulley is effected through the agency of a belt tightener comprising a jockey pulley 8 rotatably supported between the arms 9 of a pair of bell crank frames 10, only one of which is shown in Fig. 1. The arm H of each frame I 0 is mounted to swing about a pivot point l2 located beneath the drive pulley 5, the remaining arm 13 of at least one of the frames being connected to an operating cable l4 by means of which the frames l0 and the pulley 8 are swung from the dotted to the full line position shown in Fig. 1 when it is desired to tension the belt 5 to establish a drive connection between the two power pulleys. With this arrangement it will be seen that, if the lower pulley were made as large as the upper pulley, the sides of the belt 5. would contact the lower pulley even in the relaxed position indicated by dotted lines. This, of course, would entail unnecessary wear on the belt and, in some cases, the frictional contact between the lower pulley and the belt may even be sufficient to cause undesirable operation of the pulleys. that, with the arrangement shown in Fig. 1', substantial displacement of the axis of the lower pulley to either side of the vertical plane containing the axis of the upper pulley would result in contact between the lower pulley and one side of the relaxed driving belt.

Fig. 2 illustrates an improved form of loose belt drive in which the lower pulley 6 is larger than the upper pulley l, the required clearance between the lower pulley and the belt in the relaxed condition of the latter being ensured by the provision of suitable belt spreaders I5 and H arranged to work in conjunction with the jockey pulley 8. The belt spreader 56 comprises a bar or roller 20 journalled in brackets 2! (compare Figs. 2and 6) carried by the arms 9 of the frames Hi. The roller 26 is arranged to engage and move the left hand side of belt 5 to the dotted line position Y when the jockey pulley 8 is withdrawn to its inoperative position X. The belt spreader ll comprises a bar or roller 23 carried between the upper ends of a pair of vertically extending arms 24 only one of which is shown in the drawings. The lower ends of arms 2 are pivotally mounted as indicated at 25 and provided with lateral extensions Ztengaging suitable cams 2i. The'cams 27 are formed on or carried by the pivoted ends H of the frames Iii. When the jockey pulley 8 is swung from the full to the dotted line position shown in Fig. 2 the cams 21' act against the extensions 26 to swing the arms 24 outwardly so that the right hand side of the belt 5 is moved to'the dotted line position Y by the bar 23 and is thus held clear of the pulley 6. At the same time the left hand side of the belt 5 is moved from the full line position shown in Fig. 2 to the dotted line position Y by means of the roller 25 of the-belt spreader Hi. It will thus be seen'that, when the jockey pulley 8 is swung to its inoperative position X, the belt Spreaders l6 and H are auto matically moved outwardly with respect to each other to spread the sides of the belt out of contact with the lower pulley. As will be obvious from inspection of the drawings the belt spreaders l6 and H are automatically returned to the full line position shown in Fig. 2 when the jockey pulley 8 is returned to itsbelt tensioning position.

Fig. 3 shows a modification of the arrangement illustrated in Fig. 2. In this case the axis of the lower pulley 6 is offset to the right with respect to the axis of the upper pulley I. In this particular installation the spreader it, previously described in connection with Fig. 2, may be dispensed with since, in the dotted line or inoperative position of the jockey pulley 8, the left hand side of the belt will naturally fall to a relaxed position clear of the driving pulley as indicated by dotted line Y Theright hand side of the belt which tends to remain in contact with the lower pulley in the relaxed condition of the belt is moved outwardly to the dotted line position Y by means of the belt spreader I! which is identical with that previously described in connection with Fig. 2.

In the installation shown in Fig. 4, the axis of It will also be evident the lower pulley 6 is oifset to the left with respect to the axis of the upper pulley I. In this case the spreader I1 is dispensed with since the right hand side of the belt naturally falls to the dotted line position Y clear of the lower pulley ii when the belt is in the relaxed or non-running condition, the left hand side of the relaxed belt being moved to the dotted line position Y clear of pulley 6 by means of spreader it which corresponds to the spreader l8 shown in Fig. 2.

In each of the foregoing installations the frames 10 are mounted so that they normally tend to swing the jockey pulley 8 to the inoperative or dotted line position X. Movement of the jockey pulley to the operative position shown in full lines in Figs. 2, 3 and 4 is effected through the agency of the cable it which may be actuated by the manually operable winding drum as shown in Fig. 2; by the motor driven winding drum ti shown in Fig. 3; or by the hydraulic cylinder and piston device generally indicated at 32 in Fig. l.

Figs. 5, 6 and '7 show an installation similar to Fig. 4 including pressure operated means for regulating the starting and running tension applied to the belt. In this case the operating cable [4 is connected to a winding drum l la which is operated by a cable Nib connected to a pistonrod 35 attached to a piston 35 working in a cylinder 31. In the normal position of the parts the frames Hi carrying the jockey pulley 8 occupy the dotted line position shown in Fig. 5 and are supported on suitable stops 38, the piston 3i; be-

ing drawn to the right hand end of cylinder 37 as shown in Fig. '7. In this position of the parts the left hand side of the belt is held away from pulley 6 by the roller 26 of the belt spreader it. When it is desired to tension the belt fluid pressure is supplied to the right hand end of cylinder 3! by way of supply pipe 40. shut off valve 4|, pressure reducing valve 42, pipe 43, three way valve 44, and pipe 45. The piston 36 is thus moved toward the left hand end of the cylinder 3'! and acts through the cable connection Mb to swing the jockey pulley 8 from the dotted line position X to the full line position X If the movement of the jockey pulley to the position X does not provide suflicient belt tension to take care of the starting torque the full pressure of the supply line 40 is momentarily applied to the piston 36 by opening a valve :36 in a bypass 47 so that the jockey pulley is forced further to the right as indicated by dotted lines X to increase the belt tension. The valve 46 is a spring pressed valve which is normally biased to closed position so'that it will close immediately after being pressed to open position by the operator. In this connection it may be explained that the reducing valve 42 is set so that, in the closed position of the bypass valve 46, the pressure'applied to the piston 36 is closely regulated to suit the normal running torque of the paper machine section driven. from the pulley T. If this pressure is found insufficient to suit the starting torque of the section the full pressure of the supply line 40 is applied to the piston 35 by momentarily opening the bypass valve 46, said valve being released to closed position immediately after the starting period is over. The three way valve is is operable to place the pipe 45 in communication with the supply pipe if! or with an exhaust pipe 49, When the pipe 45 is connected to the exhaust pipe 49 the piston 36 is returned to the Excess pressure applied to the position 39 is relieved through the relief valve 50 and relief connection 5|.

The various valves and pipes shown in Fig. 5 may be located on the front housing 53 of the calender section of the paper making machine, the cylinder 31 being shown suspended from the calender housing by hooks 54 (see Fig. 7) engaging the I beams 55. The winding drum Ma, connected to the piston 36, is shown supported in brackets 58 carried by a suitable supporting structure 59.

Figs. 8 to 11 inclusive show a modified arrangement in which the valves 44 and 46 are replaced by a single valve 6|. This valve comprises a casing Bla provided with a port 62 connected to one end of the bypass 41 and additional ports 63, 64 and 65 connected, respectively, to the pipes 43, 49 and 45. As shown more particularly in Figs. 9 to 11 the movable elements of the valve comprise a hollow member 61 provided with three ports designated 68, 69 and 10. The high torque starting position of the valve is illustrated in Fig. 9. In this position the pipe 45 is connected to the main supply pipe by way of the bypass 41 so that the full pressure in the supply pipe 40 is applied to the piston 36 to place the driving belt under sufiicient tension to provide a high starting torque. The running position of the valve is illustrated in Fig. 10 in which it will be noted that the supply pipe 40 is connected to the pipe by way of the pressure reducing valve 42. The off position of the valve is illustrated in Fig. 11 where it will be noted that the movable element of the valve is posi tioned to' close off communication with the bypass 41 and the pressure reducing valve 42 and to establish communication between the cylinder and the exhaust connection 49,

In describing the operation of valve 6| it will be assumed that the parts are in the position shown in Fig. 11 and that it is desired to tension the belt to start'up the paper making machine. The movable valve element 61 is shifted by means of the handle 12 from the position shown in Fig. 11 to the position shown in Fig. 10, thus connecting pipe 45 to the supply line 40 by way of the reducing valve 42. c If the belt tensioning pressure thus applied to the piston 36 (Fig. 7)

is not sufficient to overcome the starting torque of the paper machine section, the full pressure of the supply line is then applied to the piston by moving the valve element 61 from the position shown in Fig. 10 to the position shown in Fig. 9, thus placing the pipe 45 in communication with the supply line 40 by way of the bypass 41. be

It is desirable that the valve 6'! be operated from the position shown in Fig. 10 to the position shown in Fig. 9 against the resistance of a spring so that, when the valve member is released after being moved to the high torque starting position shown in Fig. 9, it will be immediately returned to the running position shown in Fig. 10. To this end the valve handle 12 is arranged to operate in the slot 13 of a quadrant 14 so that, as the handle moves from the position shown in Fig. 10 to the position shown in Fig. 9, it operates against the resistance of a spring 15. This spring is arranged at the left hand end of the slot 13 with one end seated by a projection l6 carried by the adjacent end of the quadrant and with the other end seated by a projection 17 carried by a spring follower l8 which is engaged by the handle 12 as the latter is moved to the left from the position shown in Fig. 10. The handle 12 is held in the position shown in Fig. 9 until the paper machine section is started and is then released to permit it to be automatically returned to the position shown in Fig. 10 by means of the spring 15.

Having thus described my invention, what I claim is:

1. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener movable to and from an operative position with respect to one run of said belt and means functioning automatically to move both runs of the belt outwardly to a position clear of the lower pulley in response to shifting of the belt tightener to an inoperative position.

2. A loose belt drive as set forth in claim 1 in which the last mentioned means comprises a beltspreading device carried by the belt tightener and engaging one run of the belt, a second independently mounted belt spreading device engaging the opposite run of the belt and means for moving the second spreading device to an operative position in response to shifting of the belt tightener to an inoperative position.

3. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener movable to an operative belt tensioning position or to an inoperative position permitting the belt to hang loosely from the upper pulley, a belt spreading device fixed to the belt tightener to engage one run of the belt, a second independently mounted belt spreading device adapted to engage the opposite run of the belt and cam means for moving the last mentioned spreading device to and from an operative position in response to movement of the belt tightener.

4. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener for tensioning the belt around the pulleys. belt spreading devices arranged within the loop of the belt to move the two runs of the belt to positions clear of the lower pulley when the belt tightener is moved to an inoperative position, and means actuated by the belt tightener for shifting the spreading devices to an operative position in response to shifting of the belt tightener to an inoperative position and for returning the spreading devices to an inoperative position when the belt spreader is shifted to its operative position.

5. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener located outside the belt loop to exert belt tensioning pressure against one run of the belt when the tightener is moved to an operative position, a device located inside the loop of the belt to move the opposite run of the belt to a position clear of the lower pulley when the belt tightener is shifted to an inoperative position, said device comprising a rock shaft, an arm having its lower end fixed to said shaft and its upper end equipped with belt engaging means and means for rocking said shaft to move said arm to and from an operative position in response to movement of the belt tightener.

'6. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener engageable with said belt and means for operating the belt tightener and controlling the belt tensioning action thereby comprising a cylinder, a piston working in said cylinder and connected to the belt tightener,

a fluid pressure supply line, a pressure reducing valve connection betweenone end of the cylinder and the fluid pressure supply line including a pressure reducing valve and a control valve and a further connection for placing the delivery end of the cylinder in communication with the fluid supply line independently of said pressure reducing valve.

7. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener engageable with said belt and means for operating said tightener to a belt tensioning position comprising a cylinder, a piston working in said cylinder and connected to the belt tightener, a fluid pressure supply line, a connection between the supply line and one end of the cylinder including a pressure reducing valve and a further connection through which communication between the said end of the cylinder and the supply line may be established independently of the pressure reducing valve, said last mentioned connection including a manually operable valve normally biased to a closed position.

8. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener movable to and from the belt tensioning position and fluid pressure means for operating said tightener to said belt tensioning position, said means comprising a cylinder, a piston working in said cylinder and connected to the tightener, a fluid pressure supply line, a shutoff valve in said supply line, a connection between the supply line and one end of the cylinder including a pressure reducing valve and a three-way cock, the latter being operable to a position establishing communication between the cylinder and the supply line or to a position establishing communication between the cylinder and an exhaust connection, and a valve controlled bypass connection through which communication between the said end of the cylinder and the supply line may be established independently of the pressure reducing valve.

9. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener movable to and from a belt tensioning position and means for operating the belt tightener to its belt tensioning position comprising a cylinder, a piston working in said cylinder and connected to the belt tightener, a

fluid pressure supply line including a pressure reducing valve and a valve controlling communication between one end of the cylinder and said supply line, said valve being operable to a position establishing communication between the supplyline and the cylinder by way of the pressure reducing valve orto a position establishing communication between the cylinder and the supply line independently of'the pressure reducing valve or to a position disrupting communication between the cylinder and the supply line and establishing communication between the cylinder and an exhaust connection.

10. A loose belt drive comprising upper and lower pulleys, a loose drive belt trained over said pulleys, a belt tightener movable to and from a belt tensioning position and means for operating the belt tightener to its belt tensioning position comprising a cylinder, a piston working in said cylinder and connected to the belt tightener, a fluid pressure supply line, a control valve, a reducing valve through which the supply line is connected to the cylinder in one position of the control valve to apply to the piston a pres sure less than the full pressure of the supply line, a bypass through which the supply line is connected to the cylinder in another position of the control valve to apply the full supply line pressure to the piston, an exhaust line to which the cylinder is connected to another position of the control valve to permit exhaust of pressure previously supplied to the cylinder, a handle by which the valve is manually operable to each of said positions and yielding means arranged to resist movement of the valve from said first mentioned to said second mentioned positions and to automatically return the valve to said first mentioned position when it is released after being manually operated to the second mentioned position.

11. Fluid pressure means for operating and controlling the belt tensioning effect of a belt tightener, comprising a fluid pressure responsive device to which fluid pressure is applied to operate the tightener to a'" belt tensioning position, a control valve through which fluid pressure is supplied to said pressure "responsive device, said valve being operable to a'position in which a predetermined pressure is applied to said pressure responsive device 'or to a second position in which a relatively higher pressure is applied to said device, and means for automatically returning the valve to the first mentioned position when it is released after'being operated to the second mentioned position.

12. A control valve through which fluid pressure is applied to operate a pressure responsive belt tightener, said valve comprising a casing provided with a plurality of ports including a low pressure'port to which fluid is supplied from a suitable source under a definite pressure, a high pressure port to which fluid is supplied under a pressure higher than that suppliedto the first mentioned port and a third port through which the fluid supplied to the valve casing through either of the two previously mentioned portsis delivered to the pressure responsive element of the belt tightener, a movable valve element in said casing adapted tobe manually operated to a position preventing flow of fluid between the second and third ports of the casing while permitting said flow to take place between the first and third: ports, or to a second position per Initting fluid flow between the second and third ports while preventing fluid flow between the first and third ports and means arranged to yieldingly resist operation of the valve from the first to the second position and to automatically return the valve to the first position after it has been operated to the second position and released, saidvalve being also operable to a position placing the third port of the casing in communication with a relief outlet for the exhaust of pressure previouslysupplied to the pressure responsive element of thebelt tightener.

13. A loose belt drive'comprising' a pair of pulleys, a belt tightener located outside the belt loopto exert belt tensioning pressure against one run of the belt when thetightener is moved to an operative position, a cam actuated by said belt tightener, a rock shaft'equipped with an arm engaging said cam' and a belt spreading device carried by the rock shaft and located within the loop of the belt to move one run of the belt to a position'clear of the lower pulley when the belt lower pulleys, the axis of the lower pulley being ofiset to one side of the axis of the upper pulley, a belt tightener located outside the belt loop to exert belt tensioning pressure against that run of the belt which tends to fall freely away from the lower pulley when the tightener is moved to an inoperative position, a device located inside the loop of the belt to move the opposite run of the belt to a position clear of the lower pulley when the belt tightener is shifted to an inoperative position and means for actuating said device in response to shifting of the belt tightener to said inoperative position.

BERNARD A. MALKIN.

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