US2946231A

US2946231A - Paper machine drive mechanism

Info

Publication number: US2946231A
Application number: US536710A
Authority: US
Inventors: Hornbostel Lloyd
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1955-09-26
Filing date: 1955-09-26
Publication date: 1960-07-26
Anticipated expiration: 1977-07-26

Description

y 1960 L. HORNBOSTEL 2,946,231

PAPER MACHINE; DRIVE MECHANISM Filed Sept. 26, 1955 hrEz fibr' LLOYD HORNBOSTEL PAPER MACHINE DRIVE MECHANISM Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Sept. 26, 1955, Ser. No. 536,710

4 Claims. (Cl. 74-395) This invention relates to a paper machine drive mechanism, and more particularly, to an improved main drive mechanism or mechanism for a variable speed line shaft drive.-

In the usual paper machine it is important that the speed of all sections of the paper machine be capable of simultaneous variation to allow for any changes to be made in thickness, character, and quantity of paper being made in the machine. In general, the paper machine sections comprise the forming wire, the press section, the dryers (which may include more than one section), and the calender stack. All of these sections are driven through driving connections made with the variable speed line shaft. Each connection made with the line shaft drives a given section independently of the other sections and this connection will comprise a suitable speed change mechanism, since the individual sections are driven at diflerent speeds, that is, the surface speeds of the rolls or wire carrying the web in each of the sections are different. This is because the paper web itself gets longer, by pressing in the press section, and shorter, by drying in the dryers. Accordingly, the press rolls must be operated at a greater speed than the dryer rolls. A difficulty here is that the amount of stretching in the presses and the amount of shrinkage in the dryers varies with each kind of paper and with different operating speeds. The differences may be very great at high operating speeds, although not too great at lower speeds. The speed change mechanism which interconmeets the variable speed line shaft With each individual section thus is required to accommodate rather substantial differences in the ratios of speed change for different operating conditions. In recent times, paper Inachines are being operated at higher speeds than before, although such maximum speeds may not be used at all times. Accordingly, the individual speed change mechanisms have been greatly overburdened and larger more expensive and more complicated speed change mechanisms must be employed.

The instant invention affords a solution to the foregoing problem confronting the Workers in the art, permitting the use of relatively simplified and inexpensive speed change mechanisms for each of the sections. This is made possible in the instant invention by the use of a differential gearing assembly to connect two portions or members of the line shaft, so that one portion of the line shaft may operate at a speed substantially different from the speed of the other under certain conditions. By way of explanation, it will be appreciated that at relatively slow paper machine speeds both line shaft members or portions could be driven at the same speed and the individual speed change mechanisms connected to each of the paper machine sections would not be overtaXed. But when the speed of the paper machine is greatly increased, the ordinary simplified speed change mechanisms cannot handle the required changes and for this reason it has been necessary to go to additional exatent 2,946,231 Patented July 26, 1960 pense and development in an efiort to provide adequate speed change mechanisms to cover all operating speeds for the machine. In other words, at such high operating speeds the difference in the speed in the press section and the speed in the dryers becomes so great that ordinary speed change devices both connected to a line shaft operating at a single speed can impart the desired speeds to the press section of the dryers only with difficulty, if at all. In accordance with the instant invention, however, a diiferential gearing assembly is incorporated in the line shaft so that one portion of the line shaft may operate at a given lower speed which readily permits the speed change mechanism'to drive the dryer and another portion operates at a greater speed which readily permits the speed change mechanism connected with the press section to function. This permits a very substantial increase in flexibility of operation in the paper machine merely by the incorporation of one additional unit, the differential gearing assembly, in the variable speed line shaft, without the necessity of changing or replacing the various speed change mechanisms connecting the line shaft with the individual paper machine sections.

It is, therefore, an important object of the instant invention to provide an improved drive for paper machines.

It is a further object of the instant invention to provide an improved variable speed line shaft drive mechanism for paper machines which comprises a difierential gearing assembly interconnecting portions of the line shaft to accommodate greater variations in the overall paper machine speed.

Other and further objects, features and advantages of the present invention Will become apparent to those skilled in the art from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

On the drawings:

Figure 1 is essentially a diagrammatical top plan view of a paper machine drive mechanism embodying the instant invention; and

Figure 2 is an enlarged detail view of a differential gearing assembly which may be employed in the practice of the instant invention.

As shown on the drawings:

In Figure 1 there is shown diagrammatically a paper machine in plan view, indicated generally by the reference numeral 10, comprising a couch roll 11, a first press 12, a second press 13, a third press 14, (upper)

dryer rolls

15, 16, 17, 18, 19 and 20 (and lower rolls 15', 16', etc.), and a calender stack 21. A variable speed line shaft in the form of two portions or members 22a22b provides the main source of power for operating the paper machine, and the line shaft na -22b is driven by a prime mover or main drive means in the form of a steam engine 23 suitably connected by a belt and pulley arrangement 24 to the line shaft portion 22b. As will be appreciated, in the prior art paper machines the line shaft 22a22b is a unitary member not separated by differential gearing mechanism 25 (which will be described in detail hereinafter).

A suitable speed change mechanism 11a, diagrammatically shown in the form of cone pulleys and a belt, cooperating with bevel gears is driven by the line shaft member 22a and translates the line shaft speed to the speed desired for the couch roll 11. In like manner, speed change mechanisms 12a, 13w and 14a drive the first, second and third presses 12., 13 and 14, respectively. It will be appreciated that other speed change mechanisms may be employed here, but each type of speed change mechanism has certain limitations on the 3 speed changes which it can actually eifect, or which it can effect efficiently. In other words, a given speed change device can be designed to operate effectively so as to reduce the line shaft speed in rpm. to a speed of perhaps 30 to 50% of the line shaft speed; but when such speed change mechanism is called upon to selectively effect changes ranging from perhaps to as much as 80% of the iine shaft speed, the device will operate ineficiently, if at all, at such extremes. Heretofore, the line shaft speed was the same throughout the full length of the line shaft and the only known method of accommodating these changes involved making changes in the individual speed change mechanisms.

In particular, the

presses

12, 13 and 14- operate at a greater speed than the

dryer rolls

15, 16, 17, etc. With faster overall paper machine speeds, this difference becomes even greater. As will be seen, a speed change mechanism 15a is also provided to interconnect the other line shaft portion 22b and the dryer rolls, via a secondary shaft 15b and the usual bevel gear arrangement here indicated, and a speed change mechanism 21a interconnects the line shaft portion 22b and the calender stack. 21. It will thus be seen that the line shaft portion 2212 connected to the speed change mechanisms 15a and 21a for driving the dryer and calender stack may operate at a slower speed than the line shaft portion 22a which drives the

presses

12, 13 and 14. This difference in operating speeds of the line shaft portions 22-5 and 22a is accomplished by the use of a differential gearing assembly 25.

Referring to Figure 2, which shows the differential gearing assembly 25 in detail, it will be noted thatfthe line shaft portion 22b which is driven by the main drive 23 corotatably mounts a gear 26 which in turn meshes vwith and drives a gear 27 corotatably mounted on a sleeve 28 that is freely rotatable on a shaft 29. The sleeve 28 also has corotatably mounted thereon a (beveled) pinion 30. An opposed (beveled) pinion 31 is corotatably carried on still another shaft 32 and a rotatable frame 33 carried by the shaft 29 carries opposed (beveled) pinions 34 and 3-5, each of Which meshes with both of the opposed pinions 3t) and 31. The frame 33 forms the arms of a T which carry at their extremities the opposed pinions' 3'4 and 35 rotatable about the stem 29 of the T. The pinion 31 drives the shaft 32 which carries corotatably mounted thereon a gear 36 meshing with the gear 37 corotatably carried by the other line shaft portion 22a. The shaft 29 has torque imparted thereto through a coro-tatably mounted gear 38 meshing with a gear 39 directly connected to a torque-imparting unit, which in this case is a motor or drive unit 40 diagrammatically illustrated as being formed of cone pulleys 40a (on shaft 22b) and 40b (driving gear 39) with an interconnecting adjustable belt 4ilc. Other torque-imparting devices may be used for the shaft 29 of the differential gearing assembly.

As is apparent, the

opposed pinions

30 and 31 and the frame 33 (carrying the opposed pinions 34 and 35) cooperate to define a differential gearing assembly 30,- 31 and 33. The

differential gearing assembly

30, 31. and 33 permits differences in operating speeds of the. line shaft sections 22a and 22b. If the frame 33 has? sufficient torque applied thereto to hold it against rotation, and the gears are the same size as here indicated, then the speed of the driven line shaft portion 22a'would be the sameras the speed of the driving line shaft portion 22b; but, if the frame 33. is rotated in. one direction. or the other there will be differences in speed between the two: lineshaft portions 22a and 22b. As previously explained at low operating speeds there. may be no need to employ differences in line shaft speeds, but inthe higher operating speeds a distinct advantage is obtained by driving the line shaft portion 22a at a greater speed than that of the. line shaft portion 22b and the incorporation of the instant mechanism.25, thus permits much greater flexibility in the operation ofithe paper machine.

As. will be-noted in the instant arrangement, the main drive means 23- is in driving connection with the first member 2212, and one rotary gear element, the pinion 30, is in driven connection with the first member 22b, while the other rotary gear element in the form of the pinion 31 is in driving connection with the second member 22a. The remaining rotary gear element in the form of the frame 33 is the control rotary gear element in this embodiment and the unit 40 applies torque to the control element 33 in order to have the desired driving torque applied to the second member 22a.

It should be noted that in many cases only a slight speed differential (relative to the speed of the rotation of the shaft portions 22]) and 22a) is required to obtain the desired operating conditions, and the power applied or absorbed by the control element 33 in the differential gearing arrangement of this invention bears substantially the same ratio to the total power required to drive the speed controlled shaft portion 22b as the speed differential bears to the speed of the speed controlled shaft 22b. Accordingly, the controlling element 33', or the means for driving the same, in this case the unit 40 may be very small in size and readily controlled. If a separate speed controlled prime mover for the shaft portion 22a were used, such would have to be large in size and difficult to control and its control would have to be correlated precisely with that of the prime mover 23 in order to effect simultaneous changes in speed throughout the entire machine.

It will be understood that modifications and variations may be effected without departing from the spirit and scopeof the novel concepts of the present invention.

I claim as my invention:

1. In a machine of the character described, a first driven line shaft, a first plurality of variable speed drive means connecting with said line shaft, a second driven line shaft, a second plurality of variable speed drive means connecting with said second line shaft, a first plurality of driven members each of which connects with one of the first plurality of variable speed drive means and is driven thereby, a second plurality of driven members each of which connectswith one of said second plurality of variable speed drive means and is driven thereby, drive means connecting with one of the driven line shafts to drive said shaft at a base speed, a differential gear assembly con nected to the first and second line shafts and having three rotary elements, the first of said elements being connected to the line shaft which is connected to the drive means, the second of said elements being connected to the other line shaft, and the third of said elements being a control element connected to the first and second elements, and means applying torque to the control element to establish a speed difference in the other line shaft with respect to the one line shaft.

2. In a machine of the character described, a first driven line shaft, a first plurality of variable speed drive means connecting with said line shaft, a second driven lineshaft', a second plurality of variable speed drive means connecting with said second line shaft, 21 first plurality of driven members each of which connects with one of the first plurality of variable speed drive means and-is driven thereby, a second plurality of driven members each of which connects with one of said second plurality of variable speed drive means and is driven thereby, drive means connecting with one of the driven line shafts to' drive said shaft at a base speed, a differential gear assembly connected to the first and second line shafts and having three rotary elements, the first of said elements being connected to the line shaft which is connected to the drive means, the second of said elements being connected to the other line shaft, and the third of said elements being a control element connected to the first and second elements, and means applying torque to the control element to establish a speed difierence in the other line shaft with respect to a speed which may be varied from the base speed applied to the one line shaft, the second plurality of driven members being driven by the second plurality of variable speed drive means at a speed which is unaffected by the speed variation applied to the first plurality of driven members.

3. In a machine of the character described, a first driven line shaft, a first plurality of variable speed drive means connecting with said line shaft, a second driven line shaft, a second plurality of variable speed drive means connecting with said second line shaft, a first plurality of driven members each of which connects with one of the first plurality of variable speed drive means and is driven thereby, a second plurality of driven members each of which connects with one of said second plurality of variable speed drive means and is driven thereby, drive means connecting with the second driven line shaft to drive said shaft at a base speed, a difierential gear assembly connected to the first and second line shafts and having three rotary elements, the first of said elements being connected to the second line shaft, the second of said elements being connected to the first line shaft, and the third of said elements being a control element connected to the first and second elements, and means applying torque to the control element to establish a speed difference in the first line shaft with respect to the second line shaft, the first plurality of driven members being thereby driven through the first plurality of variable speed drive means and the first line shaft at a speed which may be varied from the base speed applied to the second line shaft, the second plurality of driven members being driven by the second plurality of variable speed drive means at a speed which is unaffected by the speed variation applied to the first plurality of driven members.

4. In a machine of the character described, a pair of groups of driven members, one of said groups being driven at a speed which is unaffected by the speed variation applied to the other group of driven members, a pair of groups of variable speed drive means, one of said groups being connected to said one group of driven members and the other group of variable speed drive means being connected to said other group of driven members, a pair of driven line shafts, one of said shafts being connected to said one group of variable speed drive means and the other of said shafts to the other group of variable speed drive means, drive means connected to said one line shaft to drive said shaft at a base speed, a differential gear assembly having three rotary elements, the first of said elements being connected to said other line shaft, the second of said elements being connected to said one line shaft, and the third element being a control element connected to said first and second elements, and means applying torque to the control element to establish a speed difierence in said one line shaft with respect to said other line shaft.

References Cited in the file of this patent UNITED STATES PATENTS 795,386 Cutter July 25, 1905 1,471,603 Headson Oct. 23, 1923 1,543,368 Carrier July 23, 1925 2,144,307 Hallden Jan. 17, 1939 2,180,202 Hallden Nov. 14, 1939 2,332,838 Borgward Oct. 26, 1943 2,357,201 Hornbostel Aug. 29, 1944 FOREIGN PATENTS 375,099 France June 29, 1907 726,918 France Mar. 15, 1932 857.359 France Sept. 9, 1940