US1711967A - Driving mechanism - Google Patents

Description

-May 7,1929. oBso 1,711,967

DRIVING MECHANISM Filed May 1923 3 Sheets-Sheet l I N V EN TQR. za .fofirz 1306.902:

' ATTORNEYS.

3 Sheets-Sheet 2 Tlci INVENTOR. Jfizz 0550]:

BY {5% WM ATTORNEYS.

May 7, 1929. J. ROBSON DRIVING MECHANISM Filed May 192s y 7, 1929- J. ROBSON 1,711,967

muv'me MECHANISM Filed Ma 5, 1923 s Sheets-Sheet 3 INVENTOR.

" Q Jofizz 305.5021

A TTORNEY$ Patented May. 7, .1929.

UNITED STATES, am OFFICE.

mm season, or warms,

CONNECTTCU'I, ASQIG IOR TO UNIVERSAL ENGINEER- me coaroaarron, or nonramn, cnuma, n oonrom'r-Ion or cannon.

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Application med Ha a,"

My present invention relates to driving mechanisms of the type comprising a powerdriven pump, motor mechanism operated by the fluid or liquid propelled by such pump, and suitable connections through which the liquid flows from the pump to the motor mechanism, and then back from the latter to the pump. The features to which my present invent-ion is directed relate especially to automatic mechanism for controlling the action of the pump so as to maintain a substantially constant fpressure. at the delivery port, and

' alsoto mechanism for controlling the operation of the motor mechanism, particularly when the latter comprises a plurality of motor units. This motor-controllin mechanism is preferably constructed both or man ual and for'automatic control.

The invention has been designed especially in view of the requirements of machinery for grinding timber for the production ofLpulp, where very heavy strains occur, .andwhere it is customary to operate a battery of grinderssimultaneously. It will be understood however, that the invention is susceptible 0 use in other relations, particularly in cases where a plurality of driven devices are operated from a single prime mover. Without restricting myself .to the specific disclosure made in this application, I will now proceed to describe typical and satisfactor embodiments of my present inventioil wit reference to-the accompanying drawings, in

, which Fig. 1 is a dia rammatic plan view of one arrangement em odying said invention and illustrating apump and three motors driven thereby; Fig. 2 is a longitudinal vertical section through the pump; Fig. 3 is a transverse vertical section of the pump; Fi 4 is a detail vertical section showing a slight y different arrangement of certainparts; Fig. 5 is a horizontal section through one of the controlling mechanisms associated with the respectivepnotors; Fig. dis a planview sim ilar to Fig. 1; but illustrating an arrangement in which themotors are assumed to be reversible, whereas in the arrangement shown in Figs. 1 and 5 they are supposed to always roare; in the same direction; and Fig. 7 is a.

horizontal section through one of the motor: controlling mechanisms foruse in connection with reversible motors of the type shown 1n Fig. 6.

* a In Figs. 1, 2, 3, and 6, I have showna pump of the general type disclosed, for instancqin 1953. Serial no. 686,351.

. 1 Letters Patent of the United States granted to Harvey D. Williams. on- June 15, 1909, No. 925,148 and on November 19, 1912, No. 1,044,.- 838. The shaft 15 of said pump'is journaled in a suitable'casing 16 and 1s drlven by a suitable engine or prime mover (not shown). With said shaft rotates a barrel 17 made with longitudinal cylinders 18 in which are adapted to reciprocate pistons 19, the stroke of these At 26 I have indicated in Figs. 1

and 6,

motors operated by the liquid propelled by the ump. These motors are of the same type as t e pump, at least I prefer them so, and the pipe 27 connected with the ress'ure port of t e pump delivers the liquid (oil) under pressure to the several motors, by of in- W8. termediate mechanism to be described below,

while the return pipe 28 connected with the suction port of the pump receives the liquid which has operated the motors, throu h certain connections likewise set forth elow. Thns, in the preferred form of this construe;

vtion, each motor comprises a casing havingtwo ports, similar to the pump ports 24, 25, -one;of such motor ports serving as an inlet, and the other as an outlet forthe li uid flowing through the motor. This flui operates pistons similar to the pump pistons, and

' causes the rotation of a barrel similar to the to a shaft 29 which constitutes the drive shaft for the grinder or other machine (not shown) operated by such motor. Inasmuch as the motor construction is substantially the same as that ofthe pump, and inasmuch as both pumps and motors of this type are wellknown in the art, I have deemed it unnecessaryto' show the internal construction of the 1 motor. It will be understood, however, that (as 'generallysthe case in pump-motor combinations of this character), the motor boxes corresponding to the pump box 20 are preferably held at afixed angle, while the-inclination or angle of the pump box' 20 is variable.

95 pump barrel, the motor barrel being secured o For the purpose of maintaining a constant pressure in the delivery side of the pump, I may employ the following mechanism: The, box 20 is provided with a lateral rojection or stub 30 (parallel to the sha t 15 when the swashplate 21 is per endicular to the shaft 15) having a sliding ht in a perforated ball 31 movable in a spherically curved seat in a block 32 movable along stationary slideways 33. With the block 32 is connected a rod 34 extending to a piston 35 mounted to slide in a cylinder 36. At one end, said cyl inder is connected, by a pipe 37, with the pressure port 24 of the pump, so that, whenever the pump is delivering liquid, the delivery pressure will tend to move the piston 35 in one direction and to effect a corresponding.

adjustment in the inclination of the pump swashplate 21 and in the output of the pump,

it being understood that the output of the pump (per revolution of the barrel 17) depends on the inclination of said swashplate. A counteracting force tends tomove the piston 35 in the opposite direction. As illustratedin Fig. 2, this opposing force is furnished by the weights 38 resting on a holder 39 secured to an extension 40 of the piston rod 34, and when this construction is employed, the piston rod must be vertical or at least upright. Another way of accomplishing the same result is indicated in Fig. 4, where one end of the cylinder 36 is connected with the pipe 37 as before, while the other end of said cylinder'is connected with a source of fluid under pressure, for which purpose the pressure-of the water mains might be utilized, or, as illustrated, a pipe 41 of the standpipe character might be employed, preferably in con- -nection with an elevated tank 42 containing oil or other liquid and furnishing sufiicient pressure to act as a substitute for the weights 38 of Fig. 2. With the arrangement shown in Fig. 4, the piston 35 need not move up and down, but might be placed it. any position.

In the form of my invention illustrated by Figs; 1 and 5, I have assumed that the mo tors 26 always rotate in thesame direction, that is, one port of themotor casing is always the inlet for the oil under pressure coming from the pump, and the other port of the motor casing is always the outlet for the oil which has operated such motor and is to be returned to the suction port of the. pump. In this case,.in the embodiment shown, the outlet port of each motor is connected by a branch 43 with. a pipe 44 leading to an expansion tank 45, preferably located at a saf ficiently high level to insure the complete filling of the entire pipe system connected with said tank. This tank is under atmospheric pressure, and is only partly filled, so

as to provide room for the expansion of the "oil as it heats up during the operation of the plant. Expansion tanks have been provided hitherto in pump-motor combinations of this general character, although not in the exact relation here disclosed. Any tank located at a proper level to provide the necessary head may be utilized for the function of the tank 42 of FigP4. The expansion tank is connected with the return pipe 28. Thus the return path of the oil from the motors to the pump "will be clear.

From the delivery pipe 27 of the pump branches 46 lead to ports 47 in valve casings 48, there being one such casing for each motor 26. In the position illustrated by Fig. 5,'tl1e port 47 communicates with an annular chamber or channel 49 located between the two 58 inward, until it engages the end wall of said cylinder as shown. This end of the cylinder is connected by a channel 60 with a port 61 of the valve dasing'48, and'also, by a duct or pipe 62, with the inlet port of the motor 26. In theposition illustrated by Fig. 5, the head or piston 50 cuts ofi communication between the ports 47 and 61. In this construction, the head 51 serves simply to balance thepressure on the valve, and other balancing means might be substituted; ho w ever, the construction shown has the advantage of simplicity, particularly as it enables the same kind of valve to be used both for the arrangement shown in Fig. 5 and for that of The operation of this form 0% my inven- I tion is as follows: The pump, operating in the well-known manner, sends a stream of fluid under pressure into the pipes 27 and 46.

The weights 38 (Fig. 2), or the hydrostatic pressure used as an equivalent of such.

weights (Fig. 4),will be adjusted to correspond to the desired degree' of pressure.

From the 'deivery or pressure port 24 of the pump, a portion of the oil will-pass through the pipe 37 into the eylinder 36. tendingfito move the piston 35in the direction opposite to'that infw hich it is urged by the. weights 38 or by the hydrostatic pressure. 'Thus, should the pressure in port 24 rise, the piston35 will move up,'and (since with'the apparatus illus trated thestub-30 will never move upwardly beyond the horizontal position shown) such upward movement of the piston 35wi'lldecrease the angle which said stub forms with the horizontal, and will thus bring the swashplate 21 toward the vertical position, thus reducing the output of the pump. Similarly,

any fall in the pressure at the delivery port 24 will cause the piston 35 and the stub 30 to move down, and will therefore adjust the inclination of the swashplate 21 in such a manner as to increase the output of the pump.

Therefore, if the machinery driven by themotors 26 should encounter a sudden strain, causing the pressure to rise abnormally, or should the flow of oilto the motors become throttled or obstructed for any reason, the ,pump will become adjusted automatically to "a lower output, or even, in an extreme case, to idle running (position of Fig. 2). Of course, the ump output will also be increased automatica ly under reverse conditions.

The pressure liquid from the pipes 46 will pass through the port 47 of each of the controlling mechanisms into the annular channel 49 of the valve member movable in the corresponding casing 48. Before the pump iscaused to deliver oil under pressureinto' the circuit, the valve 50. 51 is preferably set so that the channel 49 will connect the port 47 with the port 61. For this purpose, the engineer or other operator will turn the hands wheel 67 attached to the screw 65, and thus swing the lever 54 about the point 55; as a temporary fulcrum. The spring 59 is made of sufiicient strength tohold the piston 58 inthe end position shown, under normal conditions, notwithstanding the presence of oil under pressure in the channel or duct 60. The oil under pressure passes from pipe .46 through port 47, channel 49, port 61, duct 60, and pipe 62 to the respective motor 26, operating the same in the well-known manner, whereupon the oil passes from the outlet of the motor through the pipes 43, 44 to the expansiontank 45, and then returns through the pipe 28 to the suction port 25 of the pump. Should the load on themachinery driven by one of the motors '26 increase the pressure will increase correspondingly in the pipe ,62 and duct 60, thus moving the piston 58 against the action of the spring 59. At this time, the point 63 is stationary, and forms a temporary fulcrum for the lever 54, which is thus moved in such a direction as to cause the head 50 to throttle, and in extreme cases to close entirely, the port 61, thereby automatically. reducing the speed of the corresponding motor 26,- or stopping such motor altogether. There is thus provided an automatic check to the rise of-the oil pressure in the motor beyond 2a" predetermined adjustable limit, and damageto the machinery and to the motor is thus prevented. It-will be .noted that this automatid motor-control {does not interfere with the hand control obtained'by turning the screw 65, which sets thp motor forth'e desired normal speed. Also, the manual adjustment or control may be efiected at: any time,whether the machine is operating or standing v It will be noted by reference to Figs. 2 and 4 that the weights 38 or the hydrostatic pressure will tend to bring the tilting box 20 to its extreme inclination when the pump is not working, so that with the pump at rest, the stub 30 would be in its lowermost position. Evidently, it is undesirable to. start the pump in this position, but for good starting, the box 20 should be in the neutral position shown in Fig. 2. I have therefore provided a simple device for bringing the tilting box to said position beforestarting the pump. This device as shown in Fig. 2, consists of a screw 68 extending upwardly through the bottom of the pump casing 16 and adapted to engage the v68 is lowered gradually, so that the inclina tion of the tilting box will increase under the action of the weights 38 or of the hydrostatic ressure, until such action is counterbalanced y the pressure of the oil coming into the cylinder 86 through the pipe 37 As an additional safeguard, I consider it desirable to ,provide a by-pass between the pressure port 24 and the suction port 25 of the pump. This by-pass 69 is shown in Fig. 3, together with a.manually-controlled valve 70 which is closed during the normal operation of the plant, but is opened when starting the pump. The starting of the pump is thus facilitated, particularly if the stub 30 should not have been brought to an exactly horizontal or neutral position, and damage to the pump is prevented, especially in the case of the operators neglecting or forgetting to adjust the screw 68 to the position shown in Fig. 2, before starting the pump.

In Figs. 1 and 5, the motors 26 are supposed to always rotate in the same direction. Where it is desired to have the motors to ro- 'tate in one direction or the other, that is,

where the motors are reversible, I may adopt the arrangement shown in Figs. 6 and 7. The parts 46, 47, 49, 50, 51, 52, 53, 54., 55, 56, and 61 to 67 inclusive are the same as in Figs. 1 and 5. Thepipe 44, instead of being always connected with the same port of the motors, is connected with both ports, since either motor port may be the inlet or the outlet, when the motor is reversible. Pipes 43 connect the pipe 44 with one of the motor ports, and pi es 43",with the other motor ports, throug the intermediate or controlling mechanism shown in Fig. 7. Said pipes 43, 43 lead to ports of the valve casing 48 which are located on opposite sides of the port 47 which supplies oil' under pressure (from the pump). Inthe neutral position illustrated, the channel 49 communicates only with the ressure pipe 46. In operat-ion, however, t e'channel 49 communicates either with both' ports 47 and 61 (at whichtime communication betweewrt 61 and pipe 43" is cut ofi), or with the two ports 47 and 71 (at which time communication would be cut 1 port 47 communicates with port 61 or 71 reoff between port 71 and pipe 43). When I forming corresponding functions relatively to the ports 47, 61 and to the pipe 43". Port 61 leads into channel 60' which by means of pipe 62 communicates with one of the ports of motor 26. Port 71 leads to a duct 72 which by means of pipe 73 communicates with the other port of said motor 26. The channels or ducts 60 and 72 connect with opposite ends of cylinder 57 so as to lead the pressure oil to opposite faces of the piston 58 secured to the piston rod 56. In order to hold the piston 58 in the central position shown, when it is not exposed to the pressure of the oil, I may employ a spring 59' contained in a chamber or casing 74 and coiled around an extension 56 of the piston rod 56. The ends of said spring bear against plates or abutments 75, 76 movable lengthwise of said rod, and located between a collar 56" on the rod extension 56, and anut 77 on the end of said extension. The spring thus tends to keep said abutments in cont-act with the collar 56" and-with the nut 7 7 respectively.

' By a proper manipulation of the handwheel 67 of Figs. 6 and 7, the operator can shift the valve so that port 47 will communicate with either the port'61 or the port 71, and this simultaneously keeps connected, 'e1ther port 71 with pipe 43', or port 61 with pipe 43 respectively. Accordln as the adjustment is made to eifect one of t ese connections or the other, the motor will be driven in one direction or the other by the oil under pressure coming from the pump through ipe 46. As will be seen readily, this oil wi l ass from pipe 46 through port- 47 and channe 49 either to port 61 or ort 71,'acco'rding to the position of the va ve 50, 51, and will then reach one port 'of the motor either through duct and pipe 62, or throughduct 72 and pipe 73, respectively. In the event of a rise of pressure, the piston 58 will be moved in such a direction as to reduce the speed of the motor (without changin the direction in which the motor rotates). For instance, if the pressure oil is flowing to the motor through channel 60' and pipe 62, a rise in pressure will force the piston 58' toward that end of cylin der 57 which is connected with duct 72; the,

abutment 76, being in engagement with the nut 77, will move in unison with the piston 58, but the abutment 7 5', bemgin en agement with the end of the cylinder f, lf remain stationary, so that the spring 59 will be compressed. At the same time, in substantially the same manner as described with reference .to Figs. 1 and 5, the lever 54 will be swung on the point 63 as atemporary fulcrum, moving the valve 50, 51 in the same direction as the piston 58', toward the neutral position shown in Fig. 7, thus throttling or closing the communication between the ports 47 and 61. (It willbe understood that when the pressure oil is flowing to the motor through the pipe 62, the valve 50, 51 is shifted toward the port 61, from the neutral position illustrated.) On the other hand, should the pressure oil be flowing to the motor through the pipe 73, a rise in pressure will move the piston 58 toward that end of cylinder 57 which is connected with duct 60. ment 76 will remain stationary, since it engages a projection on the casing 74, and the abutment 75 will move outwardly with the piston, thus compressing the spring 59, this spring, when compressed in either way, tending to restore the piston to theformer position as soon as abnormal conditions cease. The valve 50, 51 will again be moved in the same direction as the piston 58, thus first In this case, the abut- I throttling the stream of oil at the port 71, and

Here, too, the velocity of rotation of the mo- I tor will be reduced automatically when the pressure rises, without however changing the direction in which the motor rotates. The oil leaving the motor through one of its ports passes back to the pipe 44, either'through 62, 60, 61, 43", or through73, 72,71, 43, accordingto the direction in which the motor is rotating. means of the handwheel 67, thejoperator can adjust the normal speed of each motor, whether the same be running or not, as in the form of my invention first described; furthermore, in the construction illustrated by Figs. '6 and 7, manipulation of the handwheel 67 will also enable t e operator to reverse the motors, or any on I f them individually, while the pump is propelling the oil out through the same delivery port, that is, without reversing the functions of the pump ports.

It will be understood that the means for facilitating starting of the pump, described with reference to Flgs. 2 and 3, are applicable to the form of my invention shown in Figs. 6 and 7,-as'well as to the form first described- I claim as my invention:

1. A driving mechanism, comprising a pump, a plurality of motors actuated by the fluid propelled by such pump, independent controlling mechanisms, associated with the res ective motors, each of said mechanisms inc uding a manually adjustable valve and a It will be understood that by fluid'pressure responsive member connected with said valve and interposed between the pump and motor for governing automatically the amount of fluid admitted to its respective motor as theload on the motor varies, and additional mechanism controlling the output of the pump autoinatically'in accordance with the resistance such fluid encounters in its path.

2. 'In a driving mechanism, a pump, a plurality of motors actuated. by the .fluid propelled by said pump a'balanced valve interposed in the path of the fluid from the pump to each of the motors, means under the control of the operator, for manually adjusting each of such valves individually, a piston ex posed to the pressure of the fluid flowing from the pump to the respective motors, and means, operated by the movement of said piston, for shifting said valve automatically.

without altering the I manual adjustment thereof.

3. In a drivin mechanism, a pump, a plurality of reversi le motors actuated by the fluid propelled by said pump, each motor having two ports either of which may serve as an inlet for the fluid coming from the pump, a valve interposed in the connection from the pump to each 'of the motors and controlling the flow of the fluid to one port of the motor or the other, and also controlling the cross section of the fluid current and thereby the speed of therespective motors, means under the control of the operator for manually adjusting said valve, a piston, a cylinder in which said piston is movable, connections from opposite ends of said cylinder to opposite ports of the respective motors, and a connection from said piston to the respective valve to operate the latter automatically in response to variations in the pressure of the fluid passing to the respective motors without altering the manual adjustment 'of said valve.

4. In a drivin mechanism, a pump, a plurality of reversible motors actuated by the fluid propelled by said pump, each motor having two ports either of which may serve as an inlet for the fluid coming from the pump, independent valves each interposed in the connection from the pump to the respective individual motor, and controlling flow of fluid to one port of each motor or the other port thereof, and also adapted to throttle the fluid current and thereby vary the speed of the respective motor, manually operable means under the control of the o erator, for shifting said valve to alter t e speed of the motor or to reverse such motor, and fluid pressure actuated means for each 'valve, interposed between said pump and each motor, and connected with its respective valve to actuate said valve automatically for altering the speed of the motor without reversing it or altering the manual adjustment of said valve.

5. In a driving mechanism, a pump, a reversible motor actuated by the fluid propelled by said pump and having two ports either of which may serve'as the inlet for the fluid coming from the pump, a device, under the control of the operator, for changing the speed of the motor or reversing its rotation, by governing the admission of driving fluid to the motor, and automatic means, responsive to variations in fluid pressure, associated with said motor-controlling device, for altering the speed of. the motor without reversing it.

6. In a driving mechanism, a. pump, a reversible motor actuated by thefluid propelled by said pump and having two ports either of which may serve as the inlet for the flu d coming from the pump, and a device including a manually operable valve, under the control of the operator, for directing the fluid from the pump to one motor port or the other and varying the fluid current and a fluid pressure responsive member connected with said valve for automatically operating it to vary thespeed of said motor in accordance with variations in the pressure of the fluid passingto said motor.

7. In a driving mechanism, a pump of variable output, a reversible motor actuated by the fluid propelled by said pump, and having two ports either one of which may serve as the inlet for the fluid coming from thepump, a motor-controlling device including a manually operable valve for directing the fluid from thepump to one motor port or the other and varying the fluid current and fluid pressure responsive means connected with said valve for automatically operating it to vary the speed of said motor in accordance with variations in the pressure of the'fluid passing to said motor, and an independent automatic pressure-responsive device for varying the output of the pump.

8. In a driving mechanism, a ump, a motor actuated by the fluid propelle by said pump, pipe lines connecting said pump and motor, a controlling device interposed in said pipe lines between said pump and motor, said device including a valve, a manually operable means to set said valve in adjusted position, and fluid pressure operated means connected with said valve for automatically controlling the admission of driving fluid to said motor without varying the setting of said valve.

specification.

\ JOHN ROBSON.

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