US3088564A

US3088564A - Drive system and mechanism

Info

Publication number: US3088564A
Application number: US751545A
Authority: US
Inventors: John G Grall; Edward B Nickles; Hey Roch J Van De; John D West
Original assignee: Manitowoc Engineering Co
Current assignee: Manitowoc Engineering Co
Priority date: 1958-07-28
Filing date: 1958-07-28
Publication date: 1963-05-07
Anticipated expiration: 1980-05-07

Description

DRIVE SYSTEM AND MECHANISM Filed July 28, 1958 JOHN G. GRALL EDWARD B. NICKLES ROCHE Jv VAN DE HEY JOHN D. WEST INVENTORS BY MZW AGENT United States Patent 3,088,564 DRiVE SYSTEM AND MECHANISM John G. Grail and Edward B. Nickles, Manitowoc, Roch J. Van De Hey, Whiteiaw, and John D. West, Manitowoc, Wis., assignors to Manitowoe Engineering Corporation, Manitowoc, Wis., a corporation of Wisconsin Filed July 28, 1958, Ser. No. 751,545 9 Claims. (Cl. 192.098

This invention relates to a drive system or drive mechanism for machinery, such as cranes having excavating attachments like shovels, clamshells and draglines attached thereto, and more particularly to an improved drive system and mechanism for such machines, wherein separate englnes are empioyed to power the hoisting assembly and the swing assembly thereof.

It is customary, in machinery, such as crane type excavators, to provide a drive system or mechanism which includes a single engine to drive the several functions, the power being transmitted and controlled by means of friction clutches. In such a system or mechanism the speed of the engine is customarily regulated by a governor which tends to hold a constant speed by varying the engine torque to compensate for load changes. It is necessary, therefore, for the clutches to slip while accelerating a load, resulting in the continual wear of the friction linings and requiring frequent adjustment and periodic replacement. This is particularly true of the swing clutches which are usually employed to reverse the rotation of the crane by application of the appropriate clutch to first decelerate the swing and then accelerate in the opposite direction. During such a reversal it is necessary that the clutch must slip until the crane reaches its governed swing speed, resulting in severe heating and wear of the friction surfaces.

A second drawback in the conventional single engine crane drive system or mechanism lies in the inherent inability of a single engine to maintain a given speed under changing load due to governor droop. Thus, for example, an engine laboring under a hoisting load will be further slowed by the application of a swung load with the result that cycle time is considerably greater than it would be if the swing speed were not reduced by the hoisting load.

An additional drawback in the conventional machine results from driving both the hoist and swing assemblies from the same power source whereby the speeds of these functions are not adjustable with respect to each other. As a result, it frequently happens that the speed of the hoist assembly is such that the load is raised to the maximum of the machine before the desired angle of swing is completed. It is then necessary to hold the load elevated with a brake until the swing is completed. Power is obviously wasted in such .a cycle because the load is raised faster than necessary. The converse of this also occurs in some operation, i.e., the swing must be delayed until the hoist has lifted the load sufficiently to clear a high spoil pile. Such a delay results in cycle time wasted with a resulting loss of machine efficiency.

It is an object of the present invention to provide a drive system and mechanism for machinery wherein the slipping of friction clutch devices and their consequent wear is greatly reduced.

It is a further object of the invention to provide a drive system and mechanism for machinery such as excavator cranes wherein the swing speed of the crane is unaffected by the hoisting load thereof.

An additional object of this invention is to provide a drive system and mechanism wherein the swing and hoisting speeds thereof are individually variable.

An additional object of this invention is to provide apparatus to coordinate a friction clutch control with the load thereon.

These and additional objects will 'be apparent from the following description taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a top plan view, partly in section, of a part of a machine, such as the upper works of an excavator crane, showing the drive system or mechanism of this invention employed therein, and

FIGURE 2 is a side elevational sectional view taken along the line 11-11 of FIGURE 1.

Referring now to the drawing, a machine such as an excavator crane having a rotating bed 10 is mounted on rollers (not shown) which ride on an upper surface of a roller path 12 defined by a ring gear to permit swinging of the machine about a vertical axis. A kingpin 14 is centrally fixed in the ring gear and serves to keep the rotating bed 10 centered. A swing pinion 16 engages internal gear teeth 18 in the roller path 12 to power the swinging movement of the machine.

The rotating bed 10 includes a pair of trifurcate-d boom hinge members 20 at its forward end, side frames 22 extending along each side serve to stiffen the bed 10 and also to support the several shafts which comprise the operating machinery, and engine supports 24 located adjacent to the rear of the bed 10.

A hoist system is provided for the machine and the hoist system comprises a pair of drum shafts 26-26 journaled in pillow blocks mounted on the side frames 22 and are driven through suitable gears from a counter-shaft 28 which is similarly mounted on the side frames 22 and which, in turn, is driven from a pinion 30 which is integral with a sprocket 32.

A drive system or mechanism is provided for driving the drum shafts 2626 of the hoist system as well as a swing system of the machine, to be described hereinafter, and the drive system or mechanism comprises a power source having a first engine 36, which may be called the hoist engine, and the sprocket 32 of the hoist system is driven by means of chain 34 by the first engine 36 of the power source.

The power source of the drive system or mechanism further comprises a second engine 58, which may be called the swing engine, and the swing system comprises the aforementioned swing pinion 16 which is mounted on a swing pinion shaft 38 and is driven through suitable gearing from a vertical swing shaft 40. Mounted at the top of the shaft 40 is a swing bevel gear 42 which engages, and may be driven by either of, a pair of

bevel gears

44, 46 which are rotatably mounted on a horizontal swing drive shaft 48 and driven by a pair of fluid pressure actuated swing clutch devices 50, 52 respectively, which are also mounted on the drive shaft 48 and are driven by it. The drive shaft 48 extends outwardly of the sprocket 32 and carries a sprocket 54 which is driven by a chain 56 from the second engine 58.

As shown in the drawing, the sprocket 32 and the pinion 30 are carried on anti-friction bearings (tapered roller bearings shown) mounted on the horizontal swing drive shaft 48 whereby the sprocket 32 cannot drive the drive shaft 48 but is merely positioned thereby. This arrangement is not a necessary part of the invention but is merely a convenient expedient for the conversion of a conventional machine to take advantage of the present in vention. In this respect it is to be noted that in a conventional machine the pinion 30 is normally driven by the drive shaft 48 which, in turn, is driven by a single sprocket and thus all of the machinery is driven from the drive shaft 48.

Each of the

engines

36 and 58 of the drive system or mechanism is preferably provided with a hydraulic torque converter 60. While it is not essential that hydraulic torque converters be used, it is desirable that some power transmission device he used which will permit the driven machinery to be fully stalled, at least at low engine torque, without stalling the respective engine. Such devices include so-called fluid clutches and eddy current clutches.

Each of the

engines

36 and 58 of the drive system or mechanism is further provided with a fluid pressure actuated control, which as illustrated is in the form of a conventional governor 62, including a throttle lever 64 or other suitable means whereby the speed of the respective engine may be varied.

Fluid pressure actuated drum clutch devices are provided each of which comprises a clutch spider 66 carried by each drum shaft 26 and rotatably driven thereby. Each clutch spider 66 drives a clutch shoe 68 carried thereby in a conventional manner whereby the respective clutched shoe 68 may be caused to engage a clutch drum 70 carried by a cable drum 72 rotatably mounted on each drum shaft 26'. It will thus be seen that when the clutch shoe 68 is caused to engage the clutch drum 70', the cable drum 72 will turn with the shaft 26.

For the sake of brevity, the operation of only one of the drum clutch devices will be described and it is to be noted that the clutch shoe 68 is connected by suitable linkage to a fluid pressure motor (shown schematically) carried by the clutch spider 66, which may comprise a cylinder 74 having a piston 76 therein. A spring 78 is provided to retract the clutch shoe 68 when fluid pressure is not being applied to the piston 76 to engage the clutch device.

Fluid pressure to operate the clutch device is supplied through an axial passage 80 in the drum shaft 26, a rotary joint 82, and a line 84, from modulating control valving 86 at the operators station, which in turn is supplied from a pressure fluid source 87 through suitable conduit means 89.

A second fluid pressure motor 88 is provided to operate the engine governor 62 of the hoist engine 36. This governor is arranged to advance the speed of the engine 36 upon application of fluid pressure and a retract spring 90 is provided to slow the speed of the engine 36 when fluid pressure is reduced. The throttle fluid pressure motor 88 is supplied with fluid pressure from the operators control valving 86 through a throttle control line 92.

While only the front cable drum 72 is shown and described in detail, it should be understood that the rear cable drum 72 is similar in construction and operation and is controlled by similar but separate modulating control valving 94.

Because both cable drums 7272 are driven from the same engine 36, it is necessary that the throttle pressure motor 88 be operable from either of the modulating control valving 86, 94. It is, therefore, necessary to provide means to prevent feedback from the throttle control line 92, when it is charged from one modulating valving, from entering the other clutch device pressure line and thus engaging both drum clutch devices.

A shuttle valve 96 serves as a convenient expedient for such feedback prevention. The shuttle valve 96 comprises a cylinder having an inlet passage terminating in a valve seat 98 at each end and an outlet passage 100 at its center. A shuttle 102 comprising a valve spool is freely movable in the cylinder and can seal against either valve seat 98. It should be apparent that when the modulating control valving 94 is opened to engage the rear drum clutch device, pressure fluid will enter the shuttle valve 96 and hold shuttle 102 against the opposite inlet port thus preventing the passage of fluid to the front drum clutch device but permitting fluid to flow to the throttle fluid pressure motor 88. When the modulating control valving 94 is closed and the control valve 86 is opened to engage the front drum clutch device, pressure fluid will force the shuttle 102 to the opposite end of the cylinder where it seals against the inlet seat and prevents pressure fluid from entering the line for the rear drum a clutch device. The shuttle 102 will, of course, move beyond the outlet and thus permit fluid to enter the line 92 to actuate the throttle fluid pressure moor 88. Thus either modulating control valving 86, 94 may be used to actuate its drum clutch device and the throttle of the hoist engine 36 without effecting the other drum clutch device. In the event that the modulating control valving 86, 94 are both opened at the same time, the one which is opened to the greater pressure setting will determine the position of the shuttle 102 and thus the speed of the hoist engine 36.

An essential feature of the present invention lies in the provision of apparatus for enabling the clutch

fluid pressure motors

74, 76, 78 to be responsive to a lower range of control pressures than the throttle fluid pressure motor 88. This may be accomplished through the proper selection of springs and cylinder sizes and/ or through the use of suitable linkage (not shown). Because the clutch device responds to pressures which are less than those required to actuate the throttle of the hoist engine 36. the clutch device will be engaged by increasing control pressure before the engine torque starts to increase. Since at this point the hoist engine 36 is only idling, and the torque output from the torque converter is very low, application of the drum clutch device is accomplished with a minimum of clutch wear due to the absence of high speed, high torque slippage.

As fluid pressure in the control system is further increased by the operator by means of the modulating control valving, the throttle fluid pressure motor 88 will open the governor 62 of the hoist engine 36 causing the engine torque, and consequently the torque ultimately available at the drum, to increase. However, that same pressure is available at the drum clutch device to increase the pressure of the shoe 68 on the drum 70 to permit it to transmit more torque. Thus the drum clutch device is always capable of transmitting the torque which is transmitted to it. While clutch slippage is kept to a minimum by the present system, it should be noted that at light loads the clutch devices may be engaged very gently with consequent slippage when it is desired to accelerate a load extremely slowly. However, since this slippage occurs only at light loads and slow relative speeds, the clutch life is not appreciably affected.

Construction and operation of the swing clutch devices 50, 52 is similar to that of the drum clutch devices. A pair of modulating control valving 104, 106 is connected through suitable piping and a duplex rotary seal 108, to a pair of passages in the swing shaft 48 and thence to fluid motors incorporated in the swing clutch devices 50 and 52. A shuttle valve 110 is connected between the two clutch control lines and has its outlet connected to another throttle fluid pressure motor 112 on the swing engine 58.

The clutch devices 50, 52 and throttle 62, 64 response pressures in the swing assembly are balanced by suitable apparatus in the same manner as those of the hoist assem- 'bly so that the clutch devices 50, 52 will be applied before the engine torque is increased and the clutch devices engage with a minimum of slip.

The modulating control valving 104 and 106 for the swing clutch devices 50', 52 maybe conveniently arranged to be controlled by a single actuator (not shown) which will operate either of the modulating valving depending upon the direction of motion from a neutral position, thereby permitting swing control in either direction with a single lever.

All of the clutch device control valving is supplied with pressure fluid from an engine driven source, such as the pressure fluid source 87 through the conduit means 89, which may supply a distribution manifold (not shown) to which the valving may be connected.

:In actual practice, it has been found that a Midland valve, No. XN 3440, manufactured by Midland-Ross Cooperation of Owosso, Michigan, or a Flexair type valve manufactured by Westinghouse Air Brake Company of Wilmerdin'g, Pennsylvania, will work satisfactorily as the modulating control valving 86, '94, 104 and 106 and while this valving has been illustrated in schematic manner in the drawing, it is to be understood that such valving may be of the type identified above or some other like or similar type of valving.

It will be seen that the foregoing describes a drive system or drive mechanism for a machine, such as a crane type excavator in which clutch slippage and consequent wear is minimized, in which the swing speed is entirely independent of the hoist speed and each can be individually controlled without burdening an operator with additional controls, and in which the capacities of the friction clutch devices are coordinated with the required loads.

While a preferred embodiment of the invention has been described and illustrated, it will be apparent to those slcilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention nor from the scope of the appended claims.

Having thus described our invention, we claim:

1. Drive mechanism comprising an engine,

a throttle for said engine,

a fluid pressure motor connected to said throttle,

a clutch device,

a fluid pressure motor connected to the clutch drive,

modulating valving for connecting pressure fluid to each of the motors, and

apparatus for enabling the clutch motor to be responsive to a given range of fluid pressure and for enabling the throttle motor to be responsive to a range of fluid pressure which is greater than the given range of fluid pressure of the clutch motor, said apparatus comprising a bias acting on the throttle in a throttle closing direction and a bias acting on the clutch device in a clutch releasing direction with the throttle device exerting a force greater than the force exerted by the bias of the clutch device.

2. Drive mechanism comprising an engine,

a fluid pressure advance control for the engine,

a fluid pressure actuated clutch device driven by the engine,

modulating valving for connecting a source of pressure fluid to the engine control and to the clutch device, and

apparatus for enabling said clutch device to be responsive to lower ranges of fluid pressure than the engine control.

3. Drive mechanism comprising a power source,

a fluid pressure advance control [for said power source,

a fluid pressure actuated clutch device driven by said power source, modulating valving for connecting a source of pressure fluid to the control and to the clutch device, and

apparatus for enabling the clutch device to be responsive to lower ranges of fluid pressure than the control.

4. Drive mechanism comprising a power source having a fluid pressure actuated control,

a fluid pressure responsive clutch device driven by said power source,

modulating valving for connecting pressure fluid to the clutch device and the control for the power source, and

apparatus for enabling the clutch device to be responsive to lower ranges of fluid pressure than the control for the power source.

5 A drive system for a crane, said drive system comprising an engine,

a fluid pressure actuated throttle for said engine,

apparatus for enabling said throttle to be responsive to a given range of fluid pressure,

a fluid pressure actuated clutch device driven by said engine, 7

apparatus for enabling said clutch device to be responsive to a lower range of fluid pressure than the given range of fluid pressure for said throttle, and modulat mg valvlng connecting a source of pressure fluid to said clutch device and to said throttle.

6. A drive system for an excavator crane, said drive system comprising an engine for driving a fluid pressure actuated cable drum clutch device,

a fluid pressure actuated throttle for said engine,

apparatus for enabling said clutch device to be responsive to a lower range of fluid pressure than said throttle, and modulating valving for connection a source of pressure fluid to said clutch device and to said throttle.

7. A drive system for an excavator crane, said drive system comprising an engine for driving a fluid pressure actuated swing clutch device,

a fluid pressure actuated throttle for said engine,

apparatus for enabling said clutch device to be responsive to a lower range of fluid pressure than said throttle, and modulating valving connecting a source of pressure fluid to said clutch device and to said throttle.

8. A drive system comprising an engine driving a fluid pressure engaged clutch device said engine having a fluid pressure advanced throttle, modulating valving for communicating a source of controllable pressure fluid to said clutch device and to said throttle, and

apparatus for enabling said clutch device to be responsive to a lower range of fluid pressure than said throttle to enable said clutch device to be engaged before said throttle is advanced as the pressure of the fluid is increased.

9. A drive system comprising an engine driving a fluid pressure engaged clutch device,

said engine having a fluid pressure advanced throttle, modulating valving for communicating a single source of controllable pressure fluid to said clutch device and to said throttle, and

apparatus for enabling said clutch device to be responsive to a lower range of fluid pressure than said throttle to enable a load driven by said clutch device to be accelerated first as the pressure of the fluid is increased by decreasing the slippage of the clutch device and thereafter by advancing said throttle.

References Cited in the file of this patent UNITED STATES PATENTS 941,426 Loudon Nov. 30, 1909' 2,020,888 Hight Nov. 12, 1935 2,260,631 Mitchell Oct. 28, 1941 2,338,404 Carroll Jan. 4, 1944 2,674,355 Keel Apr. 6, 1954 2,952,347 Richardson Sept. 13, 1960

Claims

1. DRIVE MECHANISM COMPRISING AN ENGINE, A THROTTLE FOR SAID ENGINE, A FLUID PRESSURE MOTOR CONNECTED TO SAID THROTTLE, A CLUTCH DEVICE, A FLUID PRESSURE MOTOR CONNECTED TO THE CLUTCH DRIVE, MODULATING VALVING FOR CONNECTING PRESSURE FLUID TO EACH OF THE MOTORS, AND APPARATUS FOR ENABLING THE CLUTCH MOTOR TO BE RESPONSIVE TO A GIVEN RANGE OF FLUID PRESSURE AND FOR ENABLING THE THROTTLE MOTOR TO BE RESPONSIVE TO A RANGE OF FLUID PRESSURE WHICH IS GREATER THAN THE GIVEN RANGE OF FLUID PRESSURE OF THE CLUTCH MOTOR, SAID APPARATUS COMPRISING A BIAS ACTING ON THE THROTTLE IN A THROTTLE CLOSING DIRECTION AND A BIAS ACTING ON THE CLUTCH DEVICE IN A CLUTCH RELEASING DIRECTION WITH THE THROTTLE DEVICE EXERTING A FORCE GREATER THAN THE FORCE EXERTED BY THE BIAS OF THE CLUTCH DEVICE.