Truck transmission jack

A lifting device for supporting transmissions and gear boxes of vehicles, said lifting device comprising in combination:

• a. a wheeled base for allowing said lifting device to be moved into a desired position under a vehicle;
• b. a cradle for engaging and supporting the underside of a transmission or gear box;
• c. first and second support arms each having first and second opposing ends, the first ends of said first and second support arms being pivotally coupled to said base along a first pivot axis, and the second ends of said first and second support arms being pivotally coupled to said cradle along a second pivot axis, said first and second support arms extending parallel to each other generally along opposing sides of said wheeled base;
• d. a hydraulic jack supported vertically upon said base, said hydraulic jack having a piston rod selectively extendable upwardly therefrom;
• e. lifting means engaged by said piston rod for being raised and lowered thereby, said lifting means being pivotally coupled to said first and second support arms along a third pivot axis located generally between said first pivot axis and said second pivot axis, said third pivot axis being generally at a lower elevation than said first pivot axis;
• and
• f. at least a third support arm having first and second opposing ends, the first end of said third support arm being pivotally coupled to said base along a fourth pivot axis, and the second end of said third support arm being pivotally coupled to said cradle along a fifth pivot axis, said first and fourth pivot axes being spaced apart from one another and lying on opposite sides of said third pivot axis to more evenly distribute weight born by said cradle across said wheeled base, said third support arm extending generally parallel to said first and second support arms for maintaining said cradle in a relatively horizontal position.

A lifting device for supporting transmissions and gear boxes of vehicles, said lifting device comprising in combination:

• a. a wheeled base for allowing said lifting device to be moved into a desired position under a vehicle;
• b. a cradle for engaging and supporting the underside of a transmission or gear box, said cradle including a generally rectangular frame having first and second opposing side members and first and second opposing end members;
• c. first and second support arms each having first and second opposing ends, the first ends of said first and second support arms being pivotally coupled to said base along a first pivot axis, and the second ends of said first and second support arms being pivotally coupled to said first and second opposing side members, respectively, of said cradle along a second pivot axis said first and second support arms extending parallel to each other generally along opposing sides of said wheeled base;
• d. a hydraulic jack supported vertically upon said base, said hydraulic jack having a piston rod selectively extendable upwardly therefrom;
• e. lifting means engaged by said piston rod for being raised and lowered thereby, said lifting means being pivotally coupled to said first and second support arms along a third pivot axis located generally between said first pivot axis and said second pivot axis;
• and
• f. at least a third support arm having first and second opposing ends, the first end of said third support arm being pivotally coupled to said base along a fourth pivot axis, and the second end of said third support arm being pivotally coupled to said cradle along a fifth pivot axis, said first and fourth pivot axes being spaced apart from one another and lying on opposite sides of said third pivot axis to more evenly distribute weight born by said cradle across said wheeled base, said third support arm extending generally parallel to said first and second support arms for maintaining said cradle in a relatively horizontal position.