US2990858A

US2990858A - Portable air driven chain saw

Info

Publication number: US2990858A
Authority: US
Inventors: Anderson G Ledger
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-05-27
Filing date: 1959-05-27
Publication date: 1961-07-04
Anticipated expiration: 1978-07-04

Description

y 1961 A. G. LEDGER 2,990,858

PORTABLE AIR DRIVEN CHAIN SAW Filed May 2'7, 1959 United States Patent 2,990,858 PORTABLE AIR DRIVEN CHAIN SAW Anderson G. Ledger, P.0. Box 853, Terra Bella, Calif. Filed May 27, 1959, Ser. No. 816,315 2 Claims. (Cl. 14332) This invention relates to saws and more particularly to an air driven portable chain saw.

It is an object of the present invention to provide a portable chain saw that can be conveniently used in all types of terrain, and which can be energized by pneumatic pressure, in the absence of a source of electrical energy.

Another object of the present invention is to provide a light weight, and easy to handle portable chain saw employing pneumatic pressure to effect operation thereof and which can be readily handled with a minimum of effort.

Other objects of the invention are to provide a portable air saw bearing the above objects in mind which is of simple construction, has a minimum number of parts, is inexpensive to manufacture and eflicient in operation.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a side elevational view, with parts broken away, of a portable air saw made in accordance with the present invention;

FIGURE 2 is a rear elevational view of the saw shown in FIGURE 1;

FIGURE 3 is an enlarged longitudinal cross sectional view of a pneumatic responsive valve mechanism for controlling operation of the saw; and

FIGURE 4 is a perspective view of this invention embodying a circular saw.

Referring now more in detail to the drawing, a portable air saw made in accordance with the present invention is shown to include a housing 12 having a handle 14 at one end into which a flexible air hose 16 extends. The innermost end of the air hose 16 is connected by means extending through said handle to a valve housing 18 having an outlet 20 that is in communication with an air motor of any desired conventional construction. Said air motor carrying and operating a chain sprocket mounted thereon (not shown). A poppet valve member 24 is movable between a normally closed seated position upon an intermediate valve seat 22 arranged at an angle with the horizontal and an open position in response to an axial force directed upon the stem 26 of the valve member 24. Said stem 26 arranged at an angle with the horizontal and with its free end outside the path of travel of the forced air from the hose. (See FIG. 1.) However, a relatively strong compression coil spring 28 acting between a trigger mechanism 30 and the valve housing 18 normally maintains the valve 24 in seated engagement with the valve seat 22. The coil spring 28 is arranged within the hollow handle, free from contact with air under pressure. The actuating trigger 30 having an upper arm and a lower arm and is pivotally carried intermediate its ends within the handle 14 upon a transversely extending pivot pin 32, and having a transverse bore in the free end of its upper arm.

The conventional air motor also mounted within the front end of the housing 12 is drivingly connected to the endless saw chain 38 that is guided along both sides of a cutting bar 34 by means of a guide pulley 33 and sprocket on said air motor. Thus, in response to actuation of the air motor by high pressure air passing through the line '1-6 in response to actuation of the trigger 30, the air motor is effective to drive the saw chain 38. A C-shaped handle 36 may be readily mounted on either side of the housing 12 intermediate its ends, to enable such saw to be used by either a right handed or a left handed person.

As shown by FIG. 4, the air motor is mounted in housing 12' and drives circular blade 38' by suitable means, and embodying trigger 30. Air hose 16' is shown attached to housing.

It will now be recognized that it is only necessary to provide a small air compressor for supplying suflicient pressure to operate the saw. Such air compressor may be conveniently driven by a small gasoline engine, in any location, and without any need for electrical energy.

While various changes may be made in the detail construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A portable pneumatically operated chain saw comprising, a longitudinal horizontally extending hollow cylindrical housing with an integral hollow handle extending downwardly and outwardly from the rear end thereof, a saw chain supporting bar secured to and extending forwardly of said cylindrical housing, a C-shaped handle mounted upon the side wall of said cylindrical housing intermediate its ends, a guide pulley rotatably mounted on the outer end of said chain supporting bar, an air motor mounted within the forward end of said cylindrical housing, a sprocket carried by said motor, an endless saw chain mounted about said pulley and said sprocket and traveling along both sides of said support bar, said air motor thereby effecting the movement of said saw chain, a valve housing arranged within said cylindrical housing in an angular position, said valve housing having an inlet and an outlet, an air hose connected with said inlet in said valve housing, a poppet valve seat arranged angularly within said valve housing, an aperture in the wall of said valve housing adjacent said hollow handle, a poppet valve arranged in said valve housing with its stem extending downwardly and rearwardly with its free end portion extending through said aperture and into said hollow handle, a bell crank type trigger pivotally mounted between its ends within said hollow handle and with its lower arm normally depending vertically outside the handle and its upper arm extending at right angles from said lower arm and having its outer free end secured to the free end of said valve stem, an air passage extending from said air inlet to said valve seat in said valve housing, a coil spring sleeved upon the free end portion of the valve stem extending outside said valve housing and free from contact with forced air passing through said passageway, the upper surface of said poppet valve being free from contact with any moving parts, and a passage for conveying forced air from said valve seat through said outlet to said motor, and air means connected with said air hose for actuating said motor when said air valve is actuated by movement of said trigger.

2. A portable pneumatically operated chain saw comprising, a longitudinally extending hollow cylindrical housing, a chain supporting bar secured to and extending outwardly in axial alignment with and from said cylindrical housing, a chain guide pulley carried by the end of said bar remote from said cylindrical housing, a downwardly and rearwardly extending hollow handle of the pistol grip type integrally formed with the rear end portion of said cylindrical housing forming a coil spring housing chamber free from air under high pressure, a bell crank type trigger pivotally mounted between its ends within the pistol grip handle and with its lower arm normally depending vertically outside the handle and its upper offset arm extending substantially at right angles from said lower arm and having a transverse bore in its free end portion and arranged Within said pistol grip handle, a conventional air motor mounted within the forward end of said cylindrical housing, a chain sprocket carried by said air motor, a valve housing angularly mounted within the rearward end of said cylindrical housing, said housing having an inlet at its rear upper end portion and an outlet in its forward lower end portion, tubular means connecting said' outlet in the lower end portion of said angular'ly arranged valve housing with said air motor, an air hose connected with said inlet means in said upper end portion of said valve housing, a valve port with a valve seat intermediate said inlet and said outlet of said valve housing, a poppet valve with a valve head and an integral angularly extending valve stem, said valve stem having a depending free end, said valve head normally closing said valve port with its top surface free from contact with any working parts, a bore in the bottom wall of said valve housing, said free end of said valve stem extending through said bore depending externally of said valve housing and free from contact with the air under pressure from said hose, said valve stem arranged in axial alignment with said pistol grip and at right angles to said offset upper arm of said trigger and having its free end connected by suitable means extending through said transverse bore in the free end of said upper arm of said trigger, a coil spring mounted upon the free end portion of said valve stem and arranged between the exterior surface of said valve housing and said upper arm of said trigger normally maintaining said valve head in seated engagement with said valve seat, said coil spring free from contact with the air under pressure from said hose whereby actuation of said trigger causes inward and upward movement of said valve stem and effecting opening of said valve port, whereby the air under pressure passes the intermediate portion of said valve stem and then past the valve seat and the underside of said valve, a chain saw trained about said guide pulley and said sprocket and traveling along both sides of said chain supporting bar, and air means connected with said air hose for actuating said motor when said air valve is actuated by said trigger.

References Cited in the file of this patent UNITED STATES PATENTS 1,260,702 Olson Mar. 26, 1918 2,351,740 Blurn June 20, 1944 2,649,871 Desbarat Aug. 25, 1953 FOREIGN PATENTS 656,811 Germany Feb. 15, 1938