CA1191044A - Method and power transmission system for operating a road planar machine - Google Patents
Method and power transmission system for operating a road planar machineInfo
- Publication number
- CA1191044A CA1191044A CA000406787A CA406787A CA1191044A CA 1191044 A CA1191044 A CA 1191044A CA 000406787 A CA000406787 A CA 000406787A CA 406787 A CA406787 A CA 406787A CA 1191044 A CA1191044 A CA 1191044A
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- machine
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- speed
- cutting unit
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Abstract
ABSTRACT
A power transmission method and apparatus for driving a road planar machine has the cutter unit in a positive mechanical drive with the drive shaft of a machine power unit through a hydraulically actuated clutch mech-anism. The wheel traction units for the machine are con-tinuously driven from the power unit by hydraulic motors operated by variable volume displacement pumps. A con-trol system for retaining the power unit at a set rota-tional speed required for a predetermined cutting or planing load is responsive to a drop in the set rotational speed, resulting from the cutting unit encountering an overload, to actuate the variable displacement pumps to decrease the forward speed of the machine without appre-ciably reducing the rotational inertia force of the cut-ting unit. If the cutting unit overload is of a short duration or momentary the set rotational speed of the power unit is resumed. If the overload, as observed by the machine operator after the occurrence of the drop in the set rotational speed of the power unit, appears to be severe or prolonged, the control system may be manually discontinued and the machine manually controlled until the cutting unit overload has been removed at which time the control system may again be placed into operation.
A power transmission method and apparatus for driving a road planar machine has the cutter unit in a positive mechanical drive with the drive shaft of a machine power unit through a hydraulically actuated clutch mech-anism. The wheel traction units for the machine are con-tinuously driven from the power unit by hydraulic motors operated by variable volume displacement pumps. A con-trol system for retaining the power unit at a set rota-tional speed required for a predetermined cutting or planing load is responsive to a drop in the set rotational speed, resulting from the cutting unit encountering an overload, to actuate the variable displacement pumps to decrease the forward speed of the machine without appre-ciably reducing the rotational inertia force of the cut-ting unit. If the cutting unit overload is of a short duration or momentary the set rotational speed of the power unit is resumed. If the overload, as observed by the machine operator after the occurrence of the drop in the set rotational speed of the power unit, appears to be severe or prolonged, the control system may be manually discontinued and the machine manually controlled until the cutting unit overload has been removed at which time the control system may again be placed into operation.
Description
PO~ER TRANSMISSION METHOD AND APPARATUS
Planar machines and saw cutting machines for road maintenance work generally drive the cutter heads and saws in a rather conventional manner directly from a power unit or through a hydraulic pump and motor. In U.S. Patent No. 2, 311,891, a road groove cutting tool is directly driven from a separate engine provided for such purposes, through a transmission mechanism and the traction units are driven through a slip-clutch from another engine.
Thus, if the cutting tool is held back by road conditions, the clutch will slip to arrest the advance travel of the machine so as to reduce the load on the cutting tool engine.
U.S. Patent No. 2,817,275 discloses a planar machine in which the cutter head is chain and sprocket driven from an engine through a clutch mechanism. The machine is manually propelled so that advancement of the cutter is readily con-trolled relative to cutting conditions. In the roadway slotting machine of U.S. Patent No. 3,321,250, the cutter is belt driven from an engine which is also used to drive traction wheels through means including a hydraulic pump to motor to differential arrangement. The road groove cutter in U.S. Patent No. 3,333,897 is in a direct engine drive connection while in Patent No. ~,139,318, the cutter head and traction units are driven in a conventionalmanner.
In the prior art devices having a belt driven cutter or a cutter having a slip-clutch connection with the power unit, the cutter rotational speed and inertia force are appreciably decreased or stopped when an obstruction is Q4~
encountered. The cutting operation is thus either stalled or takes place at a slow speed with resultant loss of time and increased expense. Where the advance travel of the machlne is continued concurrently with a positive drive of the cutter head as in U.S. Patent No. 4,13g,318, for example, the cutter head is susceptible not only to heavy tooth damage, but also damage to the power unit and/or its drive system.
~ he invention provides a power transmission method of automatically controlling the load on a single power unit that rotates a rotary cutting unit of a ground working machine and drives the machine traction units, comprising the steps of:
(a) rotating the cutting unit in a direct driven relation from the power unit, ~b) operating a pair of variable volume displace-ment pumps and associated traction motors in a direct driven relation from the power unit, (c) maintaining a set rotational speed of the power unit to drive the cutting unit at a predetermined rotational speed and the trac-tion units at a predetermined road speed, (d) actuating the variable volume displacemen-t pumps in response to a drop in the set rotational speed of the power unit to con-currently reduce the road speed of the machine and maintain the rotational inertia force of the cutting unit.
~ he invention also provides a power transmission apparatus for a gxound working machine having a rotatable material cutting unit, traction means and a power unit, said system comprising:
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a con-tinuous driven relation with said drive shaft, (c) a variable volume displacement hydraulic pump connected in a continuous driven relation with said drive shaft, 4~
(d) a traction motor for said pump, (e) means connecting the traction means in a driven relationship with said traction motor, and (f) means responsive to a decrease in a predeter-mined rotational operating speed of said power unit for reducing the volume displace-ment of said variable volume displacement pump and concurrently decreasing the linear advance speed of the machine.
Fig. 1 is a perspective view of the road planar machine which includes the power transmission apparatus;
Fig. 2 is an enlarged perspective view of the power unit and transmission system assembly with parts broken away and other parts shown in section for the purpose of clarity;
Fig. 3 is a foreshoxtened detail perspective view showing the assembly of a variable volume displacement pump with an associated drive motor for the machine traction wheels;
Fig. 4 is a diagrammatic plan view of the trans-mission system with some parts broken away for clarity;
Fig. 5 is a diagrammatic showing of a constant engine speed control system for the power unit of the trans-mission system; and Figs. 6, 7 and 8 are diagrammatic illustrations, respectively showing, the machine in normal operation; the machine encountering a road obstruction, and the machine returned to normal operation.
Referring to Fig. 1 of the drawings, there is shown a planar type machine 15 for removing a predetermined top layer of a paved road surface, that embodies the power transmission system of this invention. The machine 15 has a main frame or chassis 16 for a front end cab section 17, an intermediate power section 18 and a rear fuel and acces-sory section 19. A rotary planar or cutting unit 21 is located below the power section ]8 and between a pair of front steerable traction wheels 22 and rear traction wheels ~9~4 23. The various manually operated and controlled actuating elements for operating the machine 15 are conveniently located within the cab sec-tion 17.
In machines of this general type, the rotary eut-ting unit may be driven from a power unit by means includ-i,ng a slip clutch, or by a hydraulic system which includes a bypass or relief valve to prevent damage against any over~
load imposed on the cutting unit. In either instance, when the cutting unit engages an obstruction, so as to set up an overload condition that exceeds the adjusted setting of the slip clutch or relief valve, the centrifugal inertia force of the rotary cutting unit immediately falls off or is reduced so as to aggravate the imposed load on the cutting unit by effecting a slow down in or a stopping of the road planing opera-tion. This is especially inconvenient and time consuming when the cutting unit is repeatedly forced against the obstruction at variable speeds caused by the erratic or vacillating power delivered to the cutting unit.
Additionally, where the cutting unit is hydraulically operated, the repeated operation of a relief valve results in the heating of the oil in the hydraulic system so as to further impede a resumption of normal machine operation.
Where the power unit is in a direct mechanical drive connection with the cutting unit, appreciable damage to the cutting unit or machine may occur when an obstruc-tion is encountered due to the continued advance of the machine into the obstruction with full power applied on the cutting unit. Extreme care and attention to the road sur-face is therefore required by the machine operator to prevent machine damage and possible personal injury.
To overcome these objections, the power seetion 18 includes a power unit 24 of diesel engine type whieh is operatively eonneeted through a flexible coupling 26 (Fig.
4) to a transmission mechanism 27 that has a power take off shaft 28 gear connected in a direct driving relation with the cutting unit 21 through a hydraulieally aetuated clutch meehanism 31. When the eluteh 31 is engaged, the cutting unit 21 is driven directly from the transmission meehanism 27, and in turn from the engine 24, at a reduced rotational speed relative to the rotational speed of the take off shaft 28 through a gear reduction unit 32. The power take off shaft of the gear reduction unit 32 is connected in a one-to-one chain and sprocket drive connection 33 with the cutting unit 21.
The power shaft 28 also directly drives through a gear system 29 a pair of variable volume displacement pumps 34 and 36 of like construction, but reversely rotated in operation, having associated hydraulic motors 37 and 38, respectively, for driving the front and rear traction wheels 22 and 23, also respectively (Figs. 2, 3 and 4). In one embodiment of the invention, the pumps 34 and 36 are heavy duty Sundstrand pumps (Models 20-2065 and 20-2074), available from Sundstrand Hydro-Transmission, Ames, Iowa, a division of Sunstrand Corporation. It is seen, there-fore, that when the clutch unit 31 is engaged, the rota-tional speed of the cutting unit and linear advance of the machine are directly responsive to the rotational speed of the engine power unit 24.
The gear system 29 includes a jack shaft 30 to drive a pump 41 for supplying oil under pressure to the hydraulically actuated components of the machine such as the previously referred to clutch mechanism 31 and, as will later appear, hydro-transmission valves in the variable volume displacements pumps 34 and 36. To automatically retard the advance of the machine 15 concurrently with maintaining the centrifugal inertia force on the cutting unit 21 when there is a drop in the normal operating rota-tional speed of the engine 24, resulting from an overload condition imposed on the cutting unit, there is provided a constant engine speed control system.
The constant engine speed control system (Fig. 5) includes a twelve volt battery 42 as the electrical power source. A Honeywell W883 speed control amplifier 43, available from Honeywell, Inc. of Minneapolis, Minnesota, compares the engine speed indicated by a Honeywell SBlOOA
magnetic pulse pickup 44 with a speed set point potentio-meter 46 which is set at the normal operating speed of theengine for a normal cutting load on the cutting unit 21.
So long as the engine speed is equal to or greater than the speed set point, the output signal from the speed control amplifier 43 is approximately ten volts. This output voltage is used to power a normally manually operated con-trol handle 47 which forms part of the variable volume dis-placement pumps 34 and 36. This handle 47 operates a hydro-transmission valve 48 on each pump 34 and 36 for actuating a swash plate 49 operatively associated with pistons 51, all of which form part of the commercially available pumps 34 and 36. A position of the control handle 47 generates a variable current signal which drives the hydro-transmission valves 48 to vary the operating angle of the swash plate 49 relative to its axis of rotation, and in turn the volume displacement of the pumps 34 and 36. It is seen, therefore, that with a fixed voltage to power the control handle 47, each handle position defines a specific operating angle of the swash plates 49 and a definite volume displacement by the pumps 34 and 36.
When the engine speed falls below the desired set point speed, due to an overload on the cutting unit 21, the ten volt output signal from the speed control amplifier 43 starts to reduce or drop. This drop in the voltage supply to the control handle 47 results in a corresponding drop in the current to the hydro-transmission valves 48 and a destroking of the swash plates 49, i.e., a reduced stroke of the pistons 51 associated therewith in the variable volume displacement pumps 34 and 36 to reduce the volume of oil supplied to the traction motors 37 and 38, respectively.
This operation of the control system acts to concurrently reduce the load on the engine while maintaining the rota-tional inertia force of the cutting unit 21 to overcome the encountered overload. When the imposed load on the cutting unit has been eliminated, the control system automatically takes over for return of the engine to the set point speed.
Should there occur a failure of the speed control amplifier 43 or the encountering of a cutting unit obstruc-tion greater than can be eliminated by the reduced machinespeed, the control system does not provide for a shut down of the machine. In this event, an auto-manual switch 52 is used to provide for a manual control of the machine from the constant twelve volt battery source~ The machine operator merely manipulates the switch 52 from 'automatic' to 'manual' and continues the operation of the machine independently of the speed control system. When normal operation of the machine is to be resumed, the control system is reinstated by returning the switch 52 to its 'automatic' position.
The constant engine speed control system thus functions primarily as a load limiting system which prevents excessive loads being placed on the engine 24. Thus, when the engine speed starts to drop due to excessive loading, the system automatically cuts the load by reducing the advance of the machine and maintaining the rota-tional iner-tia of the cutting unit.
As shown in Fig. 6, the machine 15 is being operated with the cutting unit 21 removing a layer 53 of the roadway and approaching an obstruction 54. During this time the control system is operating with the ten volt out-put signal from the amplifier 43. On encountering the obstruction 54 (Fig. 7) the engine speed is reduced with a concurrent drop in the voltage to the hydro-transmission valves 48 and reduction in the volume of oil supplied to the traction motors 37 and 38. This slow down operation of the machine continues until the obstruction 54 has been removed, as shown in Fig. 8, at which time normal operation of the machine is resumed.
Planar machines and saw cutting machines for road maintenance work generally drive the cutter heads and saws in a rather conventional manner directly from a power unit or through a hydraulic pump and motor. In U.S. Patent No. 2, 311,891, a road groove cutting tool is directly driven from a separate engine provided for such purposes, through a transmission mechanism and the traction units are driven through a slip-clutch from another engine.
Thus, if the cutting tool is held back by road conditions, the clutch will slip to arrest the advance travel of the machine so as to reduce the load on the cutting tool engine.
U.S. Patent No. 2,817,275 discloses a planar machine in which the cutter head is chain and sprocket driven from an engine through a clutch mechanism. The machine is manually propelled so that advancement of the cutter is readily con-trolled relative to cutting conditions. In the roadway slotting machine of U.S. Patent No. 3,321,250, the cutter is belt driven from an engine which is also used to drive traction wheels through means including a hydraulic pump to motor to differential arrangement. The road groove cutter in U.S. Patent No. 3,333,897 is in a direct engine drive connection while in Patent No. ~,139,318, the cutter head and traction units are driven in a conventionalmanner.
In the prior art devices having a belt driven cutter or a cutter having a slip-clutch connection with the power unit, the cutter rotational speed and inertia force are appreciably decreased or stopped when an obstruction is Q4~
encountered. The cutting operation is thus either stalled or takes place at a slow speed with resultant loss of time and increased expense. Where the advance travel of the machlne is continued concurrently with a positive drive of the cutter head as in U.S. Patent No. 4,13g,318, for example, the cutter head is susceptible not only to heavy tooth damage, but also damage to the power unit and/or its drive system.
~ he invention provides a power transmission method of automatically controlling the load on a single power unit that rotates a rotary cutting unit of a ground working machine and drives the machine traction units, comprising the steps of:
(a) rotating the cutting unit in a direct driven relation from the power unit, ~b) operating a pair of variable volume displace-ment pumps and associated traction motors in a direct driven relation from the power unit, (c) maintaining a set rotational speed of the power unit to drive the cutting unit at a predetermined rotational speed and the trac-tion units at a predetermined road speed, (d) actuating the variable volume displacemen-t pumps in response to a drop in the set rotational speed of the power unit to con-currently reduce the road speed of the machine and maintain the rotational inertia force of the cutting unit.
~ he invention also provides a power transmission apparatus for a gxound working machine having a rotatable material cutting unit, traction means and a power unit, said system comprising:
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a con-tinuous driven relation with said drive shaft, (c) a variable volume displacement hydraulic pump connected in a continuous driven relation with said drive shaft, 4~
(d) a traction motor for said pump, (e) means connecting the traction means in a driven relationship with said traction motor, and (f) means responsive to a decrease in a predeter-mined rotational operating speed of said power unit for reducing the volume displace-ment of said variable volume displacement pump and concurrently decreasing the linear advance speed of the machine.
Fig. 1 is a perspective view of the road planar machine which includes the power transmission apparatus;
Fig. 2 is an enlarged perspective view of the power unit and transmission system assembly with parts broken away and other parts shown in section for the purpose of clarity;
Fig. 3 is a foreshoxtened detail perspective view showing the assembly of a variable volume displacement pump with an associated drive motor for the machine traction wheels;
Fig. 4 is a diagrammatic plan view of the trans-mission system with some parts broken away for clarity;
Fig. 5 is a diagrammatic showing of a constant engine speed control system for the power unit of the trans-mission system; and Figs. 6, 7 and 8 are diagrammatic illustrations, respectively showing, the machine in normal operation; the machine encountering a road obstruction, and the machine returned to normal operation.
Referring to Fig. 1 of the drawings, there is shown a planar type machine 15 for removing a predetermined top layer of a paved road surface, that embodies the power transmission system of this invention. The machine 15 has a main frame or chassis 16 for a front end cab section 17, an intermediate power section 18 and a rear fuel and acces-sory section 19. A rotary planar or cutting unit 21 is located below the power section ]8 and between a pair of front steerable traction wheels 22 and rear traction wheels ~9~4 23. The various manually operated and controlled actuating elements for operating the machine 15 are conveniently located within the cab sec-tion 17.
In machines of this general type, the rotary eut-ting unit may be driven from a power unit by means includ-i,ng a slip clutch, or by a hydraulic system which includes a bypass or relief valve to prevent damage against any over~
load imposed on the cutting unit. In either instance, when the cutting unit engages an obstruction, so as to set up an overload condition that exceeds the adjusted setting of the slip clutch or relief valve, the centrifugal inertia force of the rotary cutting unit immediately falls off or is reduced so as to aggravate the imposed load on the cutting unit by effecting a slow down in or a stopping of the road planing opera-tion. This is especially inconvenient and time consuming when the cutting unit is repeatedly forced against the obstruction at variable speeds caused by the erratic or vacillating power delivered to the cutting unit.
Additionally, where the cutting unit is hydraulically operated, the repeated operation of a relief valve results in the heating of the oil in the hydraulic system so as to further impede a resumption of normal machine operation.
Where the power unit is in a direct mechanical drive connection with the cutting unit, appreciable damage to the cutting unit or machine may occur when an obstruc-tion is encountered due to the continued advance of the machine into the obstruction with full power applied on the cutting unit. Extreme care and attention to the road sur-face is therefore required by the machine operator to prevent machine damage and possible personal injury.
To overcome these objections, the power seetion 18 includes a power unit 24 of diesel engine type whieh is operatively eonneeted through a flexible coupling 26 (Fig.
4) to a transmission mechanism 27 that has a power take off shaft 28 gear connected in a direct driving relation with the cutting unit 21 through a hydraulieally aetuated clutch meehanism 31. When the eluteh 31 is engaged, the cutting unit 21 is driven directly from the transmission meehanism 27, and in turn from the engine 24, at a reduced rotational speed relative to the rotational speed of the take off shaft 28 through a gear reduction unit 32. The power take off shaft of the gear reduction unit 32 is connected in a one-to-one chain and sprocket drive connection 33 with the cutting unit 21.
The power shaft 28 also directly drives through a gear system 29 a pair of variable volume displacement pumps 34 and 36 of like construction, but reversely rotated in operation, having associated hydraulic motors 37 and 38, respectively, for driving the front and rear traction wheels 22 and 23, also respectively (Figs. 2, 3 and 4). In one embodiment of the invention, the pumps 34 and 36 are heavy duty Sundstrand pumps (Models 20-2065 and 20-2074), available from Sundstrand Hydro-Transmission, Ames, Iowa, a division of Sunstrand Corporation. It is seen, there-fore, that when the clutch unit 31 is engaged, the rota-tional speed of the cutting unit and linear advance of the machine are directly responsive to the rotational speed of the engine power unit 24.
The gear system 29 includes a jack shaft 30 to drive a pump 41 for supplying oil under pressure to the hydraulically actuated components of the machine such as the previously referred to clutch mechanism 31 and, as will later appear, hydro-transmission valves in the variable volume displacements pumps 34 and 36. To automatically retard the advance of the machine 15 concurrently with maintaining the centrifugal inertia force on the cutting unit 21 when there is a drop in the normal operating rota-tional speed of the engine 24, resulting from an overload condition imposed on the cutting unit, there is provided a constant engine speed control system.
The constant engine speed control system (Fig. 5) includes a twelve volt battery 42 as the electrical power source. A Honeywell W883 speed control amplifier 43, available from Honeywell, Inc. of Minneapolis, Minnesota, compares the engine speed indicated by a Honeywell SBlOOA
magnetic pulse pickup 44 with a speed set point potentio-meter 46 which is set at the normal operating speed of theengine for a normal cutting load on the cutting unit 21.
So long as the engine speed is equal to or greater than the speed set point, the output signal from the speed control amplifier 43 is approximately ten volts. This output voltage is used to power a normally manually operated con-trol handle 47 which forms part of the variable volume dis-placement pumps 34 and 36. This handle 47 operates a hydro-transmission valve 48 on each pump 34 and 36 for actuating a swash plate 49 operatively associated with pistons 51, all of which form part of the commercially available pumps 34 and 36. A position of the control handle 47 generates a variable current signal which drives the hydro-transmission valves 48 to vary the operating angle of the swash plate 49 relative to its axis of rotation, and in turn the volume displacement of the pumps 34 and 36. It is seen, therefore, that with a fixed voltage to power the control handle 47, each handle position defines a specific operating angle of the swash plates 49 and a definite volume displacement by the pumps 34 and 36.
When the engine speed falls below the desired set point speed, due to an overload on the cutting unit 21, the ten volt output signal from the speed control amplifier 43 starts to reduce or drop. This drop in the voltage supply to the control handle 47 results in a corresponding drop in the current to the hydro-transmission valves 48 and a destroking of the swash plates 49, i.e., a reduced stroke of the pistons 51 associated therewith in the variable volume displacement pumps 34 and 36 to reduce the volume of oil supplied to the traction motors 37 and 38, respectively.
This operation of the control system acts to concurrently reduce the load on the engine while maintaining the rota-tional inertia force of the cutting unit 21 to overcome the encountered overload. When the imposed load on the cutting unit has been eliminated, the control system automatically takes over for return of the engine to the set point speed.
Should there occur a failure of the speed control amplifier 43 or the encountering of a cutting unit obstruc-tion greater than can be eliminated by the reduced machinespeed, the control system does not provide for a shut down of the machine. In this event, an auto-manual switch 52 is used to provide for a manual control of the machine from the constant twelve volt battery source~ The machine operator merely manipulates the switch 52 from 'automatic' to 'manual' and continues the operation of the machine independently of the speed control system. When normal operation of the machine is to be resumed, the control system is reinstated by returning the switch 52 to its 'automatic' position.
The constant engine speed control system thus functions primarily as a load limiting system which prevents excessive loads being placed on the engine 24. Thus, when the engine speed starts to drop due to excessive loading, the system automatically cuts the load by reducing the advance of the machine and maintaining the rota-tional iner-tia of the cutting unit.
As shown in Fig. 6, the machine 15 is being operated with the cutting unit 21 removing a layer 53 of the roadway and approaching an obstruction 54. During this time the control system is operating with the ten volt out-put signal from the amplifier 43. On encountering the obstruction 54 (Fig. 7) the engine speed is reduced with a concurrent drop in the voltage to the hydro-transmission valves 48 and reduction in the volume of oil supplied to the traction motors 37 and 38. This slow down operation of the machine continues until the obstruction 54 has been removed, as shown in Fig. 8, at which time normal operation of the machine is resumed.
Claims (6)
1. A power transmission method of automatically controlling the load on a single power unit that rotates a rotary cutting unit of a ground working machine and drives the machine trac-tion units, comprising the steps of:
(a) rotating the cutting unit in a direct driven relation from the power unit, (b) operating a pair of variable volume displacement pumps and associated traction motors in a direct driven relation from the power unit, (c) maintaining a set rotational speed of the power unit to drive the cutting unit at a predeter-mined rotational speed and the traction units at a predetermined road speed, (d) actuating the variable volume displacement pumps in response to a drop in the set rotational speed of the power unit to concurrently reduce the road speed of the machine and maintain the rotational inertia force of the cutting unit.
(a) rotating the cutting unit in a direct driven relation from the power unit, (b) operating a pair of variable volume displacement pumps and associated traction motors in a direct driven relation from the power unit, (c) maintaining a set rotational speed of the power unit to drive the cutting unit at a predeter-mined rotational speed and the traction units at a predetermined road speed, (d) actuating the variable volume displacement pumps in response to a drop in the set rotational speed of the power unit to concurrently reduce the road speed of the machine and maintain the rotational inertia force of the cutting unit.
2. The method of claim 1, wherein said step of maintaining the set rotational speed of the power unit includes the steps of: manually rendering a constant speed control system of the power unit inoperative in the event the rotational speed of the power unit drops to a predetermined rotational speed below the set rotational speed; manually controlling the operation of the cutting unit and traction units until the set rotational speed can be resumed; and then manually reinstating the constant speed control system in operation.
3. A power transmission apparatus for a ground working machine having a rotatable material cutting unit, traction means and a power unit, said system comprising:
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a contin-uous driven relation with said drive shaft, (c) a variable volume displacement hydraulic pump connected in a continuous driven relation with said drive shaft, (d) a traction motor for said pump, (e) means connecting the traction means in a driven relationship with said traction motor, and (f) means responsive to a decrease in a predetermined rotational operating speed of said power unit for reducing the volume displacement of said variable volume displacement pump and concur-rently decreasing the linear advance speed of the machine.
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a contin-uous driven relation with said drive shaft, (c) a variable volume displacement hydraulic pump connected in a continuous driven relation with said drive shaft, (d) a traction motor for said pump, (e) means connecting the traction means in a driven relationship with said traction motor, and (f) means responsive to a decrease in a predetermined rotational operating speed of said power unit for reducing the volume displacement of said variable volume displacement pump and concur-rently decreasing the linear advance speed of the machine.
4. A power transmission apparatus for a road planar machine for removing a predetermined top portion of a roadway wherein said machine has a rotatable material cutting unit, a pair of traction units and a power unit, said system comprising:
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a contin-uous driven relation with said drive shaft, (c) a pair of variable volume displacement hydraulic pumps connected in a continuous driven relation with said drive shaft, (d) a traction motor for each of said pumps, (e) means connecting a first one of said traction units in a driven relationship with one of said traction motors, (f) means connecting the second one of said traction units in a driven relation with the second one of said traction motors, and (g) means responsive to a decrease in a predetermined rotational operating speed of said power unit for reducing in unison the volume displacement of said variable volume displacement pumps and concurrently decreasing the linear advance speed of the machine.
(a) a drive shaft for said power unit;
(b) means connecting said cutting unit in a contin-uous driven relation with said drive shaft, (c) a pair of variable volume displacement hydraulic pumps connected in a continuous driven relation with said drive shaft, (d) a traction motor for each of said pumps, (e) means connecting a first one of said traction units in a driven relationship with one of said traction motors, (f) means connecting the second one of said traction units in a driven relation with the second one of said traction motors, and (g) means responsive to a decrease in a predetermined rotational operating speed of said power unit for reducing in unison the volume displacement of said variable volume displacement pumps and concurrently decreasing the linear advance speed of the machine.
5. The apparatus of claim 1 or 2, wherein: said means connect-ing said cutting unit includes a hydraulically actuated clutch mechanism.
6. The apparatus of claim 1 or 2, wherein said drive shaft and connecting means include m e a n s connecting a speed trans-mission unit in said drive shaft at a position adjacent the power unit for simultaneously varying the rotational speeds of said variable volume displacement pumps and said cutting unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000406787A CA1191044A (en) | 1982-07-07 | 1982-07-07 | Method and power transmission system for operating a road planar machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000406787A CA1191044A (en) | 1982-07-07 | 1982-07-07 | Method and power transmission system for operating a road planar machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1191044A true CA1191044A (en) | 1985-07-30 |
Family
ID=4123166
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000406787A Expired CA1191044A (en) | 1982-07-07 | 1982-07-07 | Method and power transmission system for operating a road planar machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1191044A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110058617A (en) * | 2018-01-18 | 2019-07-26 | 爱德利科技股份有限公司 | The control method of electric hydaulic power assist system |
-
1982
- 1982-07-07 CA CA000406787A patent/CA1191044A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110058617A (en) * | 2018-01-18 | 2019-07-26 | 爱德利科技股份有限公司 | The control method of electric hydaulic power assist system |
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