Office Action 1: Non-Final Rejection (2025-02-26)
Rejection types: 102 - Lack of Novelty, 103 - Obviousness

CLAIMS:
CLAIMS

1\. A machine comprising:
a main body mounted to a chassis;
a swing system for rotating the main body relative to the chassis;
a travel system for driving the machine across a terrain; and
a swing-travel hydraulic system comprising:a swing-travel pump arrangement;
a swing motor arrangement operably mounted to the swing system for
rotating the main body;a travel motor arrangement operably mounted to the travel system for driving the machine; and
a swing-travel valve system configured to:
selectively fluidly connect the swing motor arrangement to the
swing-travel pump arrangement in a closed loop swing circuit for rotating the main body; andselectively fluidly connect the travel motor arrangement to the swing-travel pump arrangement in a closed loop travel circuit for driving the machine.

2\. The machine of claim 1 wherein:
the travel motor arrangement comprises at least one left travel motor and at least one right travel motor;
the closed loop travel circuit comprises first and second closed loop travel
circuits; andthe swing-travel valve system is configured to:
selectively fluidly connect the at least one left travel motor to the swing- travel pump arrangement in the first closed loop travel circuit; and
selectively fluidly connect the at least one right travel motor to the swing-
travel pump arrangement in the second closed loop travel circuit.

3\. The machine of claim 1 or claim 2 wherein the swing-travel pump arrangement comprises first and second travel pumps.

4\. The machine of claims 2 and 3 wherein the swing-travel valve system is configured to selectively fluidly connect the at least one left travel motor to the first travel pump in the first closed loop travel circuit and selectively fluidly connect the at least one right travel motor to the second travel pump in the second closed loop travel
circuit.

5\. The machine of claim 4 wherein the swing-travel valve system is configured to selectively fluidly connect the first and second closed loop travel circuits for driving in a straight direction and fluidly isolate the first and second closed loop travel
circuits for steering the machine whilst driving.

6\. The machine of any one of the preceding claims wherein the swing-travel valve system is configured to fluidly isolate the closed loop swing and travel circuits from each other such that the swing motor arrangement is controllable independently of
the travel motor arrangement.

7\. The machine of any one of claims 3 to 6 wherein the swing-travel pump arrangement further comprises a swing pump, the swing-travel valve system being configured to selectively fluidly connect the swing pump to the swing motor
arrangement.

8\. The machine of claim 7 wherein the swing-travel valve system is configured to selectively fluidly connect the swing pump to the swing motor arrangement in fluid isolation to the first and second travel pumps and fluidly connect
the swing motor arrangement to the first travel, second travel and swing pumps simultaneously.

9\. The machine of any one of the preceding claims further comprising an implement system and an implement hydraulic system, the implement hydraulic system
comprising:at least one implement actuator;
an implement pump arrangement; and
an implement valve system configured to connect the implement pump arrangement to the at least one implement actuator in an open loop circuit.

10\. The machine of claim 9 wherein pressurised fluids in each of the swing- travel and implement hydraulic systems are fluidly isolated from one another.

11\. The machine of any one of the preceding claims wherein:
the travel motor arrangement is mounted to the chassis;
the swing-travel pump arrangement and swing-travel valve system are mounted to the main body; and
the travel motor arrangement is fluidly connected to the swing-travel valve
system through the swing system.

12\. A method of operating a machine, the machine comprising:
a main body mounted to a chassis;
a swing system for rotating the main body relative to the chassis;
a travel system for driving the machine across a terrain; and
a swing-travel hydraulic system comprising:a swing-travel pump arrangement;
a swing motor arrangement operably mounted to the swing system;
a travel motor arrangement operably mounted to the travel system; and a swing-travel valve system, wherein the method comprises:operating the swing-travel valve system to fluidly connect the swing motor arrangement to the swing-travel pump arrangement in a closed loop swing circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the closed loop swing circuit
to operate the swing system to rotate the main body about the chassis;and operating the swing-travel valve system to fluidly connect the travel motor arrangement to the swing-travel pump arrangement in a closed loop travel circuit and operating the swing-travel pump
arrangement to direct hydraulic fluid around the closed loop travel circuit to operate the travel system to drive the machine across a terrain.

13\. The method of claim 12 wherein:

the travel motor arrangement comprises at least one left travel motor and at least one right travel motor;
the closed loop travel circuit comprises first and second closed loop travel circuits; and
the method further comprises:operating the swing-travel valve system to selectively fluidly connect the at least one left travel motor to the swing-travel pump arrangement in the first closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the first closed loop travel circuit to drive the
machine across a terrain in a right direction of travel; andoperating the swing-travel valve system to selectively fluidly connect the at least one right travel motor to the swing-travel pump arrangement in a second closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the second closed loop travel circuit to drive the
machine across a terrain in a left direction of travel.

14\. The method of claim 12 or claim 13 comprising operating the swing- travel valve system to fluidly isolate the swing and travel closed loop circuits from each other and thereby operate the swing motor arrangement independently of the travel
motor arrangement.

15\. The method of any one of claims 12 to 14 wherein the machine further comprises:
at least one implement; and
an implement hydraulic system comprising:at least one implement actuator;
an implement pump arrangement; and an implement valve system,
wherein the method further comprises operating the implement valve system to
fluidly connect the implement pump arrangement to the at least one implement actuator in an open loop circuit, wherein during operation pressurised fluids in each of the swing- travel and implement hydraulic systems are fluidly isolated from one another. 5 10 15 20 25 30

OFFICE ACTION:
DETAILED ACTION
Notice of Pre-AIA  or AIA  Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 12/05/2023 has been considered by the examiner.
Drawings
The drawings are objected to because the unlabeled rectangular box(es) shown in the drawings should be provided with descriptive text labels. See MPEP  608.02(b), FP:6.22, Examiner Note 1.
Applicant’s Fig. 2, ‘45’ points to an unlabeled box.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-4, 6-7, and 11-14 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Knussman et al. (US 2013/0098011), hereinafter ‘Knussman’.
Knussman discloses:
1. (Original) A machine comprising: a main body (18) mounted to a chassis (39); a swing system (43) for rotating the main body relative to the chassis; a travel system (40L, 40R) for driving the machine across a terrain (24); and a swing-travel hydraulic system comprising: a swing-travel pump arrangement (66 in circuits 62 and 58); a swing motor arrangement (60, 43) operably mounted to the swing system for rotating the main body; a travel motor arrangement (42L, 42R) operably mounted to the travel system for driving the machine; and a swing-travel valve system (76, 78, 80, 82, 90) configured to: selectively fluidly connect the swing motor arrangement (60, 43) to the swing-travel pump arrangement (66) in a closed loop swing circuit for rotating the main body; and
selectively fluidly connect the travel motor arrangement (58) to the swing-travel pump arrangement (66) in a closed loop travel circuit for driving the machine (see Fig. 2, closed loop circuits are shown).
2. (Original) The machine of claim 1 wherein: the travel motor arrangement comprises at least one left travel motor (42L) and at least one right travel motor (42R): the closed loop travel circuit comprises first and second closed loop travel circuits (62, 58); and the swing-travel valve system is configured to: selectively fluidly connect the at least one left travel motor to the swing-travel pump arrangement in the first closed loop travel circuit (valves 76, 78, 80, 82 in circuit 62 selectively connects the left travel motor 42L to the swing-travel pump arrangement 66 in circuit 62); and selectively fluidly connect the at least one right travel motor to the swing-travel pump arrangement in the second closed loop travel circuit (valves 76, 78, 80, 82 in circuit 58 selectively connects the left travel motor 42R to the swing-travel pump arrangement 66 in circuit 58).
3. (Currently Amended) The machine of claim 1 wherein the swing-travel pump arrangement comprises first and second travel pumps (pumps 66 in circuits 62 and 58).
4. (Currently Amended) The machine of claim 2 wherein the swing-travel valve system is configured to selectively fluidly connect the at least one left travel motor to the first travel pump in the first closed loop travel circuit (valves 76, 78, 80, 82 in circuit 62 selectively connects the left travel motor 42L to the first pump 66 in circuit 62) and selectively fluidly connect the at least one right travel motor to the second travel pump in the second closed loop travel circuit (valves 76, 78, 80, 82 in circuit 58 selectively connects the left travel motor 42R to the second travel pump 66 in circuit 58).
6. (Currently Amended) The machine of claims 1 wherein the swing-travel valve system is configured to fluidly isolate the closed loop swing and travel circuits from each other such that the swing motor arrangement is controllable independently of the travel motor arrangement (valve 90 isolates the closed loop swing circuit 60 from the closed loop travel circuit 58 that includes travel motor 42R).
7. (Currently Amended) The machine of claims 3 wherein the swing-travel pump arrangement further comprises a swing pump (66 in circuit 60), the swing-travel valve system being configured to selectively fluidly connect the swing pump to the swing motor arrangement circuit (valves 76, 78, 80, 82 in circuit 60 selectively connects the swing motor 43 to the swing pump 66 in circuit 60).
11. (Currently Amended) The machine of claim 1 wherein: the travel motor arrangement is mounted to the chassis (see Fig. 1, travel motors 42L, 42R are mounted to the chassis 39); the swing-travel pump arrangement and swing-travel valve system are mounted to the main body (swing travel arrangement 43 mounted to main body); and the travel motor arrangement is fluidly connected to the swing-travel valve system through the swing system (travel motor arrangement 42R fluidly connected to swing travel valve system 76, 78, 80, 82 in circuit 60 via valve 90, which is part of the swing system, all valves are mounted on the work machine, and therefore mounted either directly or indirectly to the main body, swing system, and chassis).
12. (Original) A method of operating a machine, the machine comprising: a main body mounted to a chassis; a swing system for rotating the main body relative to the chassis; a travel system for driving the machine across a terrain; and a swing-travel hydraulic system comprising: a swing-travel pump arrangement; a swing motor arrangement operably mounted to the swing system; a travel motor arrangement operably mounted to the travel system; and a swing-travel valve system (see claim 1 rejection for equivalent limitation mapping and discussion),
wherein the method comprises: operating the swing-travel valve system to fluidly connect the swing motor arrangement to the swing-travel pump arrangement in a closed loop swing circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the closed loop swing circuit to operate the swing system to rotate the main body about the chassis; and operating the swing-travel valve system to fluidly connect the travel motor arrangement to the swing-travel pump arrangement in a closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the closed loop travel circuit to operate the travel system to drive the machine across a terrain (paragraph [0025], [0026] [0030], [0031], [0034], [0035] apparent from hydraulic circuit seen in Fig. 2).
13. (Original) The method of claim 12 wherein: the travel motor arrangement comprises at least one left travel motor and at least one right travel motor; the closed loop travel circuit comprises first and second closed loop travel circuits (see previous rejections for equivalent limitation mapping and discussion); and the method further comprises: operating the swing-travel valve system to selectively fluidly connect the at least one left travel motor to the swing-travel pump arrangement in the first closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the first closed loop travel circuit to drive the machine across a terrain in a right direction of travel (paragraph [0016], [0022]-[0025], [0034]); and
operating the swing-travel valve system to selectively fluidly connect the at least one right travel motor to the swing-travel pump arrangement in a second closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the second closed loop travel circuit to drive the machine across a terrain in a left direction of travel (paragraph [0016], [0022]-[0025], [0034]).
14. (Currently Amended) The method of claim 12 comprising operating the swing-travel valve system to fluidly isolate the swing and travel closed loop circuits from each other and thereby operate the swing motor arrangement independently of the travel motor arrangement (when valve 90, 84 is closed, the swing circuit is isolated from the travel circuit and thereby operates independently, see Fig. 2, paragraph [0030]).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 5 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Knussman in view of Asakage et al. (US 2006/0266029), hereinafter ‘Asakage’.
Regarding claim 5, Knussman discloses the machine of claim 4 but does not disclose wherein the swing-travel valve system is configured to selectively fluidly connect the first and second closed loop travel circuits for driving in a straight direction and fluidly isolate the first and second closed loop travel circuits for steering the machine whilst driving.
However, Asakage discloses a work machine similar to Knussman and the present application and therefore constitutes analogous art. Asakage discloses a swing control valve 56, a left travel motor 18L controlled by valve 42, a right travel motor 18R controlled by valve 52, wherein the left travel motor is normally supplied fluid with P2 and the right travel motor is normally supplied fluid with P1 in separate circuit sections. Asakage teaches merging flows from the two separate pumps P1 and P2 in separate circuit sections with a merge valve 60 during straight travel operation to ensure constant straight travel by preventing unequal fluid flow and pressures to the left and right travel motors (paragraph [0039], [0055]). While Asakage is directed towards open loop circuits, the teaching of merging flows from unconnected circuits supplied by separate pumps using a merge valve still applies to closed circuits for the same benefits.
Since ensuring straight travel operations is beneficial, and Knussman discusses that “straight travel may be facilitated by generating substantially equal output speeds and rotational directions from left and right-travel motors 42L, 42R” (Knussman paragraph [0016]), it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Knussman to have implemented a merge valve between the two circuit sections driving the left and right travel motors to combine the fluid output of the two separate pumps so that the amount of fluid and pressure supplied to both travel motors are equal to ensure straight travel operations as taught by Asakage. The implemented merge valve 60 as taught by Asakage would be places between circuits 62 and 58 of Knussman as these two circuits include the left and right travel motors 42L, 42R, and would be opened when straight travel is desired by the operator to ensure that the two travel motors operate at the same speed and thus travels straight. The proposed modification results in a system
wherein the swing-travel valve system (Knussman 66,58) is configured to selectively fluidly connect the first and second closed loop travel circuits (Knussman 66 and 58) for driving in a straight direction and fluidly isolate the first and second closed loop travel circuits for steering the machine whilst driving (The implemented merge valve of Asakage is taught to be closed while driving the machine in a turning operation, paragraph [0050], [0052] discloses independent travel motor valve control).
The combination of Knussman and Asakage further renders obvious:
8. (Original) The machine of claim 7 wherein the swing-travel valve system is configured to selectively fluidly connect the swing pump to the swing motor arrangement in fluid isolation to the first and second travel pumps (configuration seen in Knussman Fig. 2 with valve 84 closed) and fluidly connect the swing motor arrangement to the first travel, second travel and swing pumps simultaneously (Knussman paragraph [0046] discloses opening combining valve 84 during a swinging operation to supplement the flow provided to the swing motor; one of ordinary skill in the art would recognize that during a straight traveling operation and a simultaneous swinging operation, the combining valve 84 would be open, and the implemented merge valve as taught by Asakage would also be open, which results in fluidly connecting the swing motor arrangement to the first travel, second travel, and swing pump simultaneously).
Claim(s) 9, 10, 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Knussman in view of Asakage as applied to claim 5 and 8 above, and further in view of Wetzel et al. (US 2004/0060747), hereinafter ‘Wetzel’.
Regarding claim 9, Knussman discloses the machine of claim 1 further comprising an implement system and an implement hydraulic system (Knussman, implements 26, 32, with hydraulic systems seen in Fig. 2), the implement hydraulic system comprising: at least one implement actuator (Knussman 54); an implement pump arrangement (Knussman pump 66 in circuit 64);
Knussman does not disclose an implement valve system configured to connect the implement pump arrangement to the at least one implement actuator in an open loop circuit. However, Asakage discloses an open loop implement pump arrangement to the at least one implement actuator in an open loop circuit (Asakage Fig. 1).
Further, Wetzel discloses a hydraulic machine similar to Knussman and the present application and therefore constitutes analogous art. Wetzel discloses a closed loop travel motor circuit (Wetzel Fig. 3) used in the same machine as an open loop implement hydraulic circuit having its own implement pump supplying fluid to an implement 301 through valves 305 (Wetzel Fig. 4, paragraph [0023]). Wetzel teaches that having separate circuits allow for significantly less effects between the travel systems and implement operation (Wetzel paragraph [0023]).
Since using a closed loop circuits for operating travel motors of a hydraulic work machine in combination with an open loop circuit for operating implements is a known configuration in the art, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have further modified the system of Knussman in view of Asakage to have an implement system and an implement hydraulic system, the implement hydraulic system comprising: at least one implement actuator; an implement pump arrangement; and an implement valve system configured to connect the implement pump arrangement to the at least one implement actuator in an open loop circuit as taught by Wetzel. When applying the teachings of Wetzel to the system of Knussman, implement circuit 64 would be modified to be an open loop circuit as taught by Wetzel as a matter of simple substitution of one known configuration for another to yield only the expected result of a functioning implement hydraulic circuit that is able operate an implement hydraulic cylinder.
The combination of Knussman, Asakage, and Wetzel further renders obvious:
10. (Original) The machine of claim 9 wherein pressurised fluids in each of the swing-travel and implement hydraulic systems are fluidly isolated from one another (Knussman, Fig. 2, circuit 64 is fluidly isolated from the swing-travel system 58).
15. (Currently Amended) The method of claims 12 wherein the machine further comprises: at least one implement; and an implement hydraulic system comprising: at least one implement actuator; an implement pump arrangement; and an implement valve system, wherein the method further comprises operating the implement valve system to fluidly connect the implement pump arrangement to the at least one implement actuator in an open loop circuit, wherein during operation pressurised fluids in each of the swing-travel and implement hydraulic systems are fluidly isolated from one another (see claim 9 and 10 rejection for equivalent limitation mapping and discussion, the combination of Knussman, Asakage, and Wetzel renders obvious claim 15, the system of Knussman has fluidly separate implement circuit 64 relative to the other circuits, and the teaching from Wetzel renders obvious using an open loop circuit for the implement circuit 64 instead of a closed loop circuit as a matter of simple substitution).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Cosoli et al. (US 2016/0377097), Kondo et al. (US 11214942) both disclose systems having both closed loop circuit travel circuit and open loop implement circuit


NEXT OFFICE ACTION: DETAILED ACTION
Notice of Pre-AIA  or AIA  Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant’s amended drawings remedies the drawing objection raised in the office action dated 02/26/2025, therefore the drawing objection has been withdrawn.
Applicant's arguments filed 05/27/2025 pertaining to the prior art rejections have been fully considered but they are not persuasive.
Applicant’s remarks state that the prior art does not disclose the amended limitations of claim 1 of “an implement system and an implement hydraulic system for operating the implement system; wherein pressurised fluids in each of the swing-travel and implement hydraulic systems are fluidly isolated from one another” and states that applicant’s “implement system” includes all of the hydraulic cylinders in the system while the prior art does not.
However, under the broadest reasonable interpretation, the claimed limitations do not require that all hydraulic cylinders of the system are included in the recited “implement system”. Applicant should amend the claims to explicitly recite the argued feature if this is what is intended to be claimed. As currently written, the prior art still reads on the claims because “an implement system” is met by any partial portion of the system, such as circuit 64 of Knussman which has an implement hydraulic cylinder 48 and its own fluidly isolated circuit 64. While applicant’s specification may state that all hydraulic cylinders are included in the recitation of “implement system”, it is improper to import limitations from the specification into the claims.
See below for updated rejections.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-4, 6-7, and 11-14 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Knussman et al. (US 2013/0098011), hereinafter ‘Knussman’.
Knussman discloses:
1. (Original) A machine comprising: a main body (18) mounted to a chassis (39); a swing system (43) for rotating the main body relative to the chassis; a travel system (40L, 40R) for driving the machine across a terrain (24); and a swing-travel hydraulic system comprising: a swing-travel pump arrangement (66 in circuits 62 and 58); a swing motor arrangement (60, 43) operably mounted to the swing system for rotating the main body; a travel motor arrangement (42L, 42R) operably mounted to the travel system for driving the machine; and a swing-travel valve system (76, 78, 80, 82, 90) configured to: selectively fluidly connect the swing motor arrangement (60, 43) to the swing-travel pump arrangement (66) in a closed loop swing circuit for rotating the main body; and
selectively fluidly connect the travel motor arrangement (58) to the swing-travel pump arrangement (66) in a closed loop travel circuit for driving the machine (see Fig. 2, closed loop circuits are shown);
an implement system (34) and an implement hydraulic system (64) for operating the implement system
wherein pressurised fluids in each of the swing-travel and implement hydraulic systems are fluidly isolated from one another (Knussman, Fig. 2, circuit 64 is fluidly isolated from the swing-travel system 58).
2. (Original) The machine of claim 1 wherein: the travel motor arrangement comprises at least one left travel motor (42L) and at least one right travel motor (42R): the closed loop travel circuit comprises first and second closed loop travel circuits (62, 58); and the swing-travel valve system is configured to: selectively fluidly connect the at least one left travel motor to the swing-travel pump arrangement in the first closed loop travel circuit (valves 76, 78, 80, 82 in circuit 62 selectively connects the left travel motor 42L to the swing-travel pump arrangement 66 in circuit 62); and selectively fluidly connect the at least one right travel motor to the swing-travel pump arrangement in the second closed loop travel circuit (valves 76, 78, 80, 82 in circuit 58 selectively connects the left travel motor 42R to the swing-travel pump arrangement 66 in circuit 58).
3. (Currently Amended) The machine of claim 1 wherein the swing-travel pump arrangement comprises first and second travel pumps (pumps 66 in circuits 62 and 58).
4. (Currently Amended) The machine of claim 2 wherein the swing-travel valve system is configured to selectively fluidly connect the at least one left travel motor to the first travel pump in the first closed loop travel circuit (valves 76, 78, 80, 82 in circuit 62 selectively connects the left travel motor 42L to the first pump 66 in circuit 62) and selectively fluidly connect the at least one right travel motor to the second travel pump in the second closed loop travel circuit (valves 76, 78, 80, 82 in circuit 58 selectively connects the left travel motor 42R to the second travel pump 66 in circuit 58).
6. (Currently Amended) The machine of claims 1 wherein the swing-travel valve system is configured to fluidly isolate the closed loop swing and travel circuits from each other such that the swing motor arrangement is controllable independently of the travel motor arrangement (valve 90 isolates the closed loop swing circuit 60 from the closed loop travel circuit 58 that includes travel motor 42R).
7. (Currently Amended) The machine of claims 3 wherein the swing-travel pump arrangement further comprises a swing pump (66 in circuit 60), the swing-travel valve system being configured to selectively fluidly connect the swing pump to the swing motor arrangement circuit (valves 76, 78, 80, 82 in circuit 60 selectively connects the swing motor 43 to the swing pump 66 in circuit 60).
11. (Currently Amended) The machine of claim 1 wherein: the travel motor arrangement is mounted to the chassis (see Fig. 1, travel motors 42L, 42R are mounted to the chassis 39); the swing-travel pump arrangement and swing-travel valve system are mounted to the main body (swing travel arrangement 43 mounted to main body); and the travel motor arrangement is fluidly connected to the swing-travel valve system through the swing system (travel motor arrangement 42R fluidly connected to swing travel valve system 76, 78, 80, 82 in circuit 60 via valve 90, which is part of the swing system, all valves are mounted on the work machine, and therefore mounted either directly or indirectly to the main body, swing system, and chassis).
12. (Original) A method of operating a machine, the machine comprising: a main body mounted to a chassis; a swing system for rotating the main body relative to the chassis; a travel system for driving the machine across a terrain; and a swing-travel hydraulic system comprising: a swing-travel pump arrangement; a swing motor arrangement operably mounted to the swing system; a travel motor arrangement operably mounted to the travel system; and a swing-travel valve system (see claim 1 rejection for equivalent limitation mapping and discussion),
wherein the method comprises: operating the swing-travel valve system to fluidly connect the swing motor arrangement to the swing-travel pump arrangement in a closed loop swing circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the closed loop swing circuit to operate the swing system to rotate the main body about the chassis; and operating the swing-travel valve system to fluidly connect the travel motor arrangement to the swing-travel pump arrangement in a closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the closed loop travel circuit to operate the travel system to drive the machine across a terrain (paragraph [0025], [0026] [0030], [0031], [0034], [0035] apparent from hydraulic circuit seen in Fig. 2);
an implement system (34) and an implement hydraulic system (64) for operating the implement system
wherein pressurised fluids in each of the swing-travel and implement hydraulic systems are fluidly isolated from one another (Knussman, Fig. 2, circuit 64 is fluidly isolated from the swing-travel system 58).
13. (Original) The method of claim 12 wherein: the travel motor arrangement comprises at least one left travel motor and at least one right travel motor; the closed loop travel circuit comprises first and second closed loop travel circuits (see previous rejections for equivalent limitation mapping and discussion); and the method further comprises: operating the swing-travel valve system to selectively fluidly connect the at least one left travel motor to the swing-travel pump arrangement in the first closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the first closed loop travel circuit to drive the machine across a terrain in a right direction of travel (paragraph [0016], [0022]-[0025], [0034]); and
operating the swing-travel valve system to selectively fluidly connect the at least one right travel motor to the swing-travel pump arrangement in a second closed loop travel circuit and operating the swing-travel pump arrangement to direct hydraulic fluid around the second closed loop travel circuit to drive the machine across a terrain in a left direction of travel (paragraph [0016], [0022]-[0025], [0034]).
14. (Currently Amended) The method of claim 12 comprising operating the swing-travel valve system to fluidly isolate the swing and travel closed loop circuits from each other and thereby operate the swing motor arrangement independently of the travel motor arrangement (when valve 90, 84 is closed, the swing circuit is isolated from the travel circuit and thereby operates independently, see Fig. 2, paragraph [0030]).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 5 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Knussman in view of Asakage et al. (US 2006/0266029), hereinafter ‘Asakage’.
Regarding claim 5, Knussman discloses the machine of claim 4 but does not disclose wherein the swing-travel valve system is configured to selectively fluidly connect the first and second closed loop travel circuits for driving in a straight direction and fluidly isolate the first and second closed loop travel circuits for steering the machine whilst driving.
However, Asakage discloses a work machine similar to Knussman and the present application and therefore constitutes analogous art. Asakage discloses a swing control valve 56, a left travel motor 18L controlled by valve 42, a right travel motor 18R controlled by valve 52, wherein the left travel motor is normally supplied fluid with P2 and the right travel motor is normally supplied fluid with P1 in separate circuit sections. Asakage teaches merging flows from the two separate pumps P1 and P2 in separate circuit sections with a merge valve 60 during straight travel operation to ensure constant straight travel by preventing unequal fluid flow and pressures to the left and right travel motors (paragraph [0039], [0055]). While Asakage is directed towards open loop circuits, the teaching of merging flows from unconnected circuits supplied by separate pumps using a merge valve still applies to closed circuits for the same benefits.
Since ensuring straight travel operations is beneficial, and Knussman discusses that “straight travel may be facilitated by generating substantially equal output speeds and rotational directions from left and right-travel motors 42L, 42R” (Knussman paragraph [0016]), it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Knussman to have implemented a merge valve between the two circuit sections driving the left and right travel motors to combine the fluid output of the two separate pumps so that the amount of fluid and pressure supplied to both travel motors are equal to ensure straight travel operations as taught by Asakage. The implemented merge valve 60 as taught by Asakage would be places between circuits 62 and 58 of Knussman as these two circuits include the left and right travel motors 42L, 42R, and would be opened when straight travel is desired by the operator to ensure that the two travel motors operate at the same speed and thus travels straight. The proposed modification results in a system
wherein the swing-travel valve system (Knussman 66,58) is configured to selectively fluidly connect the first and second closed loop travel circuits (Knussman 66 and 58) for driving in a straight direction and fluidly isolate the first and second closed loop travel circuits for steering the machine whilst driving (The implemented merge valve of Asakage is taught to be closed while driving the machine in a turning operation, paragraph [0050], [0052] discloses independent travel motor valve control).
The combination of Knussman and Asakage further renders obvious:
8. (Original) The machine of claim 7 wherein the swing-travel valve system is configured to selectively fluidly connect the swing pump to the swing motor arrangement in fluid isolation to the first and second travel pumps (configuration seen in Knussman Fig. 2 with valve 84 closed) and fluidly connect the swing motor arrangement to the first travel, second travel and swing pumps simultaneously (Knussman paragraph [0046] discloses opening combining valve 84 during a swinging operation to supplement the flow provided to the swing motor; one of ordinary skill in the art would recognize that during a straight traveling operation and a simultaneous swinging operation, the combining valve 84 would be open, and the implemented merge valve as taught by Asakage would also be open, which results in fluidly connecting the swing motor arrangement to the first travel, second travel, and swing pump simultaneously).
Claim(s) 9, 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Knussman in view of Asakage as applied to claim 5 and 8 above, and further in view of Wetzel et al. (US 2004/0060747), hereinafter ‘Wetzel’.
Regarding claim 9, Knussman discloses the machine of claim 1, the implement hydraulic system comprising: at least one implement actuator (Knussman 54); an implement pump arrangement (Knussman pump 66 in circuit 64);
Knussman does not disclose an implement valve system configured to connect the implement pump arrangement to the at least one implement actuator in an open loop circuit. However, Asakage discloses an open loop implement pump arrangement to the at least one implement actuator in an open loop circuit (Asakage Fig. 1).
Further, Wetzel discloses a hydraulic machine similar to Knussman and the present application and therefore constitutes analogous art. Wetzel discloses a closed loop travel motor circuit (Wetzel Fig. 3) used in the same machine as an open loop implement hydraulic circuit having its own implement pump supplying fluid to an implement 301 through valves 305 (Wetzel Fig. 4, paragraph [0023]). Wetzel teaches that having separate circuits allow for significantly less effects between the travel systems and implement operation (Wetzel paragraph [0023]).
Since using a closed loop circuits for operating travel motors of a hydraulic work machine in combination with an open loop circuit for operating implements is a known configuration in the art, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have further modified the system of Knussman in view of Asakage to have an implement system and an implement hydraulic system, the implement hydraulic system comprising: at least one implement actuator; an implement pump arrangement; and an implement valve system configured to connect the implement pump arrangement to the at least one implement actuator in an open loop circuit as taught by Wetzel. When applying the teachings of Wetzel to the system of Knussman, implement circuit 64 would be modified to be an open loop circuit as taught by Wetzel as a matter of simple substitution of one known configuration for another to yield only the expected result of a functioning implement hydraulic circuit that is able operate an implement hydraulic cylinder.
The combination of Knussman, Asakage, and Wetzel further renders obvious:
15. (Currently Amended) The method of claims 12 wherein the implement hydraulic system further comprises: at least one implement actuator; an implement pump arrangement; and an implement valve system, wherein the method further comprises operating the implement valve system to fluidly connect the implement pump arrangement to the at least one implement actuator in an open loop circuit, (see claim 1 and 9 rejection for equivalent limitation mapping and discussion, the combination of Knussman, Asakage, and Wetzel renders obvious claim 15, the system of Knussman has fluidly separate implement circuit 64 relative to the other circuits, and the teaching from Wetzel renders obvious using an open loop circuit for the implement circuit 64 including an implement valve system instead of a closed loop circuit as a matter of simple substitution).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.

CITED REFERENCE SUMMARIES: Ref US20130098011A1: Claims:
A hydraulic system, comprising: a first circuit fluidly connecting a first pump to a swing motor in a closed-loop manner; a second circuit fluidly connecting a second pump to a first travel motor and a first linear tool actuator in a parallel closed-loop manner; and a combining valve configured to selectively fluidly connect the first circuit to the second circuit.
a first circuit fluidly connecting a first pump to a swing motor in a closed-loop manner;
a second circuit fluidly connecting a second pump to a first travel motor and a first linear tool actuator in a parallel closed-loop manner; and
a combining valve configured to selectively fluidly connect the first circuit to the second circuit.
The hydraulic system of claim 1 , further including a third circuit fluidly connecting a third pump to tandem-operating second linear tool actuators and to a second travel motor in a parallel closed-loop manner.
The hydraulic system of claim 2 , further including a fourth circuit fluidly connecting a fourth pump to a third linear tool actuator in closed-loop manner.
The hydraulic system of claim 3 , further including: at least a first metering valve associated with the swing motor; at least a second metering valve associated with the first linear tool actuator; at least a third metering valve associated with the first travel motor; at least a fourth metering valve associated with the second linear tool actuators; and at least a fifth metering valve associated with the second travel motor.
at least a first metering valve associated with the swing motor;
at least a second metering valve associated with the first linear tool actuator;
at least a third metering valve associated with the first travel motor;
at least a fourth metering valve associated with the second linear tool actuators; and
at least a fifth metering valve associated with the second travel motor.
The hydraulic system of claim 4 , wherein the at least a first, at least a second, at least a third, and least a fourth, and at least a fifth metering valves each includes a set of four independent metering valves.
The hydraulic system of claim 4 , wherein the fourth circuit is a meterless circuit.
The hydraulic system of claim 3 , wherein the first pump has a capacity of about half of a capacity of the second pump and about a third a capacity of the third pump.
The hydraulic system of claim 7 , wherein the second and fourth pumps have about equal capacities.
The hydraulic system of claim 8 , wherein each of the first, second, third, and fourth pumps are over-center variable-displacement pumps.
The hydraulic system of claim 9 , wherein each of the first and second travel motors are fixed displacement motors.
The hydraulic system of claim 10 , wherein the swing motor is an over-center variable-displacement motor.
The hydraulic system of claim 3 , wherein each of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator are simultaneously operable.
The hydraulic system of claim 12 , wherein the combining valve is capable of selectively combining fluid flows from the first and second circuits during simultaneous operation of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator.
The hydraulic system of claim 1 , wherein the combining valve is a solenoid-operated variable-position valve that is spring biased from a flow-passing first position toward a flow-blocking second position.
The hydraulic system of claim 1 , wherein the combining valve includes: a first solenoid-operated variable-position valve associated with discharge passages of the first and second circuits; and a second solenoid-operated variable-position valve associated with intake passages of the first and second circuits.
a first solenoid-operated variable-position valve associated with discharge passages of the first and second circuits; and
a second solenoid-operated variable-position valve associated with intake passages of the first and second circuits.
The hydraulic system of claim 1 , wherein the combining valve is a solenoid-operated variable-position valve that is movable between a first position at which fluid is allowed to flow between a first passage of the first circuit and a first passage of the second circuit and between a second passage of the first circuit and a second passage of the second, a second position at which fluid is allowed to flow between the first passage of the first circuit and the second passage of the second circuit and between the second passage of the first circuit and the first passage of the second circuit, and a third position at which fluid flow through the combining valve is inhibited.
A hydraulic system, comprising: a first circuit fluidly connecting an over-center variable-displacement first pump to an over-center variable-displacement swing motor in a closed-loop manner; a second circuit fluidly connecting an over-center variable-displacement second pump to a fixed-displacement first travel motor and a first linear tool actuator in a parallel closed-loop manner; a combining valve configured to selectively fluidly connect the first circuit to the second circuit; a third circuit fluidly connecting an over-center variable-displacement third pump to tandem-operating second linear tool actuators and to a fixed-displacement second travel motor in a parallel closed-loop manner; a fourth circuit fluidly connecting an over-center variable-displacement fourth pump to a third linear tool actuator in closed-loop manner; at least a first metering valve associated with the swing motor; at least a second metering valve associated with the first linear tool actuator; at least a third metering valve associated with the first travel motor; at least a fourth metering valve associated with the second linear tool actuators; and at least a fifth metering valve associated with the second travel motor, wherein: the fourth circuit is a meterless circuit; each of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator are simultaneously operable; and the combining valve is capable of selectively combining fluid flows from the first and second circuits during simultaneous operation of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator.
a first circuit fluidly connecting an over-center variable-displacement first pump to an over-center variable-displacement swing motor in a closed-loop manner;
a second circuit fluidly connecting an over-center variable-displacement second pump to a fixed-displacement first travel motor and a first linear tool actuator in a parallel closed-loop manner;
a combining valve configured to selectively fluidly connect the first circuit to the second circuit;
a third circuit fluidly connecting an over-center variable-displacement third pump to tandem-operating second linear tool actuators and to a fixed-displacement second travel motor in a parallel closed-loop manner;
a fourth circuit fluidly connecting an over-center variable-displacement fourth pump to a third linear tool actuator in closed-loop manner;
at least a fifth metering valve associated with the second travel motor,
wherein: the fourth circuit is a meterless circuit; each of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator are simultaneously operable; and the combining valve is capable of selectively combining fluid flows from the first and second circuits during simultaneous operation of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator.
the fourth circuit is a meterless circuit;
each of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator are simultaneously operable; and
the combining valve is capable of selectively combining fluid flows from the first and second circuits during simultaneous operation of the swing motor, first travel motor, first linear actuator, second linear actuators, and third linear actuator.
A method of operating a hydraulic system, comprising: pressurizing fluid with a first pump and a second pump; directing fluid from the first pump to a swing motor and from the swing motor back to the first pump via a closed-loop first circuit; directing fluid from the second pump to a first linear actuator and to a first travel motor in parallel and from the first linear actuator and travel motor back to the second pump via a closed-loop second circuit; and selectively combining fluid from the first circuit with fluid from the second circuit.
pressurizing fluid with a first pump and a second pump;
directing fluid from the first pump to a swing motor and from the swing motor back to the first pump via a closed-loop first circuit;
directing fluid from the second pump to a first linear actuator and to a first travel motor in parallel and from the first linear actuator and travel motor back to the second pump via a closed-loop second circuit; and
selectively combining fluid from the first circuit with fluid from the second circuit.
The method of claim 18 , further including: pressurizing fluid with a third pump and a fourth pump; directing fluid from the third pump to tandem-operating second linear actuators and to a second travel motor in parallel and from the second linear actuators and the second travel motor back to the third pump in a closed-loop manner; and directing fluid from the fourth pump to a third linear actuator in a closed-loop manner.
pressurizing fluid with a third pump and a fourth pump;
directing fluid from the third pump to tandem-operating second linear actuators and to a second travel motor in parallel and from the second linear actuators and the second travel motor back to the third pump in a closed-loop manner; and
directing fluid from the fourth pump to a third linear actuator in a closed-loop manner.
The method of claim 19 , further including selectively metering fluid into only the swing motor, the first linear actuator, the first travel motor, the second linear actuators, and the second travel motor.
Ref US20060266029A1: Claims:
A working machine comprising: left and right traveling units operating by means of the supply of hydraulic fluid from a hydraulic fluid supply source; and a hydraulic pressure supply apparatus, the hydraulic pressure supply apparatus including: a first hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the left traveling unit; a second hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the right traveling unit; a first travel control valve disposed between the left traveling unit and the first hydraulic pump, the first travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the first hydraulic pump to a tank-side flow channel, the first travel control valve leading an amount of the hydraulic fluid from the first hydraulic pump in proportion to an operational amount of the first travel control valve from the neutral position to another position to the left traveling unit; a second travel control valve disposed between the right traveling unit and the second hydraulic pump, the second travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the second hydraulic pump to a tank-side flow channel, the second travel control valve leading an amount of the hydraulic fluid from the second hydraulic pump in proportion to an operational amount of the second control valve from the neutral position to another position to the right traveling unit; at least one actuator control valve connected to at least one of the tank-side flow channels of the first travel control valve and the second travel control valve, the actuator control valve being switchable between a neutral position and driving position, the neutral position meaning that hydraulic fluid flowing through the tank-side flow channel is directly led to the tank side, the driving position meaning that the hydraulic fluid flowing through the tank-side flow channel is led to a predetermined actuator different from the left and right traveling units; a straight-ahead travel control valve being switchable between a block position and merge position, the block position meaning that a first hydraulic supply channel starting from the first hydraulic pump to the first travel control valve is blocked from a second hydraulic supply channel starting from the second hydraulic pump to the second travel control valve, the merge position meaning that the first hydraulic supply channel is connected to the second hydraulic supply channel so as to merge hydraulic fluid ejected from the first hydraulic pump and hydraulic fluid ejected from the second hydraulic pump; a third hydraulic pump separately disposed from the first hydraulic pump and the second hydraulic pump; a hydraulic feed channel for leading hydraulic fluid ejected from the third hydraulic pump to the predetermined actuator so as to feed the hydraulic fluid to the predetermined actuator; a feed switching valve being switchable between a feed position and block position, the feed position meaning that the third hydraulic pump is connected to the hydraulic feed channel, the block position meaning that the third hydraulic pump is disconnected from the hydraulic feed channel; and switching control means for switching the straight-ahead travel control valve and the feed switching valve to the block positions when at least one of the first travel control valve and the second travel control valve remains at the neutral position or when all of the actuator control valves remain at the neutral positions and switching the straight-ahead travel control valve to the merge position and the feed switching valve to the feed position when both the first travel control valve and the second travel control valve are operated from the neutral positions by a predetermined operational amount and when at least one of the actuator control valves is operated from the neutral position to the driving position.
left and right traveling units operating by means of the supply of hydraulic fluid from a hydraulic fluid supply source; and
a hydraulic pressure supply apparatus, the hydraulic pressure supply apparatus including:
a first hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the left traveling unit;
a second hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the right traveling unit;
a first travel control valve disposed between the left traveling unit and the first hydraulic pump, the first travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the first hydraulic pump to a tank-side flow channel, the first travel control valve leading an amount of the hydraulic fluid from the first hydraulic pump in proportion to an operational amount of the first travel control valve from the neutral position to another position to the left traveling unit;
a second travel control valve disposed between the right traveling unit and the second hydraulic pump, the second travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the second hydraulic pump to a tank-side flow channel, the second travel control valve leading an amount of the hydraulic fluid from the second hydraulic pump in proportion to an operational amount of the second control valve from the neutral position to another position to the right traveling unit;
at least one actuator control valve connected to at least one of the tank-side flow channels of the first travel control valve and the second travel control valve, the actuator control valve being switchable between a neutral position and driving position, the neutral position meaning that hydraulic fluid flowing through the tank-side flow channel is directly led to the tank side, the driving position meaning that the hydraulic fluid flowing through the tank-side flow channel is led to a predetermined actuator different from the left and right traveling units;
a straight-ahead travel control valve being switchable between a block position and merge position, the block position meaning that a first hydraulic supply channel starting from the first hydraulic pump to the first travel control valve is blocked from a second hydraulic supply channel starting from the second hydraulic pump to the second travel control valve, the merge position meaning that the first hydraulic supply channel is connected to the second hydraulic supply channel so as to merge hydraulic fluid ejected from the first hydraulic pump and hydraulic fluid ejected from the second hydraulic pump;
a third hydraulic pump separately disposed from the first hydraulic pump and the second hydraulic pump;
a hydraulic feed channel for leading hydraulic fluid ejected from the third hydraulic pump to the predetermined actuator so as to feed the hydraulic fluid to the predetermined actuator;
a feed switching valve being switchable between a feed position and block position, the feed position meaning that the third hydraulic pump is connected to the hydraulic feed channel, the block position meaning that the third hydraulic pump is disconnected from the hydraulic feed channel; and
switching control means for switching the straight-ahead travel control valve and the feed switching valve to the block positions when at least one of the first travel control valve and the second travel control valve remains at the neutral position or when all of the actuator control valves remain at the neutral positions and switching the straight-ahead travel control valve to the merge position and the feed switching valve to the feed position when both the first travel control valve and the second travel control valve are operated from the neutral positions by a predetermined operational amount and when at least one of the actuator control valves is operated from the neutral position to the driving position.
The working machine according to claim 1 , wherein the straight-ahead travel control valve includes a pilot-operated directional control valve capable of being switched from the block position to the merge position when receiving a pilot pressure greater than or equal to a predetermined pressure, and the feed switching valve includes a pilot-operated directional control valve capable of being switched from the block position to the feed position when receiving a pilot pressure greater than or equal to a predetermined pressure, and wherein the switching control means further includes a pilot pressure supply circuit and a pilot hydraulic fluid supply source connected to the straight-ahead travel control valve and the feed switching valve, and wherein the pilot pressure supply circuit limits the supply of pilot pressure from the pilot hydraulic fluid supply source to the straight-ahead travel control valve and the feed switching valve so as to switch the straight-ahead travel control valve and the feed switching valve to the block positions when at least one of the first travel control valve and the second travel control valve remains at the neutral position or when all of the actuator control valves remain at the neutral positions, and wherein the pilot pressure supply circuit switches the straight-ahead travel control valve to the merge position and leads a pilot pressure sufficient for switching the feed switching valve to the feed position from the pilot hydraulic fluid supply source to the straight-ahead travel control valve and the feed switching valve when both the first travel control valve and the second travel control valve are operated from the neutral positions by more tha
[Truncated to input limit]