US3865213A

US3865213A - Chain saw oiling system

Info

Publication number: US3865213A
Authority: US
Inventors: John W Mcdermott
Original assignee: Beaird Poulan Inc
Current assignee: White Consolidated Industries Inc; Beaird Poulan Inc
Priority date: 1972-10-25
Filing date: 1972-10-25
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

A chain saw oiling system comprises an automatic pump for continuously pumping oil from a reservoir to the saw chain of a chain saw and the manual pump adapted to prime the automatic pump, to purge foreign matter from the system, and to supply additional oil whenever the output of the automatic pump is insufficient for the proper lubrication of the saw chain. Both of the pumps are mounted in a pump housing which is detachably secured to the chain saw. The automatic pump comprises a relatively small piston and a diaphragm which is actuated by pressure pulses developed in the crankcase in the engine of the chain saw to continuously reciprocate the piston. The manual pump is located upstream from the automatic pump and comprises a relatively large piston adapted for manual reciprocation.

Description

United States Patent McDermott 1 CHAIN SAW OILING SYSTEM [58] Field Inventor:

Assignee:

Filed:

Appl.

John W. McDermott, Shreveport, La.

Beaird-Poulan, 1nc., Shreveport, La.

Oct. 25, 1972 US. Cl 123/196 CP, 83/169, 184/28,

Int. Cl. Fl6n 13/08, FOlm 1/04 of Search 184/15 R, 26, 28, 29; 123/196 CP; 83/169 References Cited UNITED STATES PATENTS [4 1 Feb. 11, 1975 Primary Examiner-Mauel A. Antonakas Attorney, Agent, or Firm-1-1ubbard, Thurman, Turner & Tucker 57 ABSTRACT A chain saw oiling system comprises an automatic pump for continuously pumping oil from a reservoir to the saw chain of a chain saw and the manual pump adapted to prime the automatic pump, to purge foreign matter from the system, and to supply additional oil whenever the output of the automatic pump is insufficient for the proper lubrication of the saw chain. Both of the pumps are mounted in a pump housing which is detachably secured to the chain saw. The automatic pump comprises'a relatively small piston and a diaphragm which is actuated by pressure pulses developed in the crankcase in the engine of the chain saw to continuously reciprocate the piston. The manual pump is located upstream from the automatic pump and comprises a relatively large piston adapted for manual reciprocation.

13 Claims, 5 Drawing Figures [U FEB] l 1373 SHEEI 3 OF 3 FIG.

FIG

FIG.5

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a chain saw oiling system, and more particularly to a system for oiling saw chains including both an automatic pump and an auxiliary manual pump.

As is well known, chain saws typically comprises a saw chain which is driven around a guide bar by an inter-nal combustion engine. In the operation of such a saw it is desirable to apply oil to the saw chain on a more or less continuous basis. This is necessary not only to lubricate the saw chain in its movement around the guide bar, but also to prevent undue accumulations of sawdust, sap, etc., on the saw chain.

Various systems for oiling saw chains have been provided heretofore. Thus, systems incorporating a separate pump driven directly by the engine of the chain saw have been provided, as have systems wherein the pump incorporates one or more parts of the engine, such as the crankshaft. In chain saws incorporating two cycle engines, crankcase pressure has also been utilized to force oil to the saw chain. The latter systems typically comprise means for pressurizing an oil reservoir to cause oil flow to the saw chain, and an auxiliary pump adapted to force oil through the oil passageway should it become blocked.

Notwithstanding the foregoing and other attempts at providing a workable chain saw oiling system a number of problems have remained unsolved. Thus, particu larly in the case of the small, lightweight type of chain saw that is popular at the present time, the crankcase and other major components of a chain saw often comprise relatively complicated die castings. It has been found that if the chain saw oiling system is integrated into these components, leaks can develop in the oiling system which are difficult if not impossible to isolate. Such a leak can impede or even completely prevent the proper operation of the chain saw oiling system. Also, even if a leak is located, it may be impossible to correct without replacing one or more major castings.

The present invention comprises a novel chain saw oiling system which overcomes the foregoing and other difficulties that have long been associated with the prior art. In accordance with the broader aspects-of the invention the oiling system includes an automatic pump comprising a diaphragm mounted in a pump housing which is detachably secured to a chain saw. The diaphragm is actuated by pressure pulses developed in the crankcase of theengine of the chain saw, and functions to reciprocate a first piston in a first pumping cylinder formed in the pump housing whenever the engine is running. By this means oil'is continuously pumped from an oil reservoir through an inlet passageway, through an oil passageway formed in the pump housing, and through an outlet passageway to the saw chain of the chain saw.

The chain oiling system further includes a manual pump comprising a piston mounted for reciprocation in a second pumping cylinder formed in the pump housing. The piston of the manual pump is substantially larger than the piston of the automatic pump, and the manual pump must be located upstream from the automatic pump. By this means the manual pump functions to prime the automatic pump, to purge foreign matter out of the automatic pump, and to supply additional oil whenever the quantity of oil supplied by the automatic pump is insufficient for proper lubrication of the saw chain.

In accordance with more specific aspects of the invention, inlet and outlet check valves common to both of the pumps are located at the opposite ends of the oil passageway formed in the pump housing. By this means any leaks that might occur are isolated at the pump housing and are therefore readily isolated and corrected. A spring is provided for normally reciprocating the piston of the automatic pump to a position wherein oil flow through the oil passageway is permitted under the action of the manual pump. The diaphragm is mounted in a diaphragm chamber which communicates with the pumping cylinder of the automatic pump. A relatively large passageway extends from the crankcase of the engineto the side of the diaphragm opposite the spring for reciprocating the piston of the automatic pump against the action of the spring. A relatively small passageway extends from the crankcase to the opposite side of the diaphragm for relieving pressure in the diaphragm chamber.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following Detailed Descrip tion when taken in conjunction with the accompanying Drawings, wherein: FIG. 1 is a top'view of a chain saw utilizing an oiling system incorporating the invention;

FIG. 2 is a sectional view taken generally along the line 2-2 in FIG. 1;

FIG. 3 is an exploded view of the oiling system;

FIG. 4 is a sectional view taken generally along the line 4-4 in FIG. 1; and

FIG. 5 is a schematic illustration of the cooperation between the various component parts of the oiling systern.

DETAILED DESCRIPTION Referring now to the Drawings, and particularly to FIGS. 1 and 2 thereof, there is shown a chain saw 10 including a chain oiling system 12 constructed in accordance with the present invention. The chain saw 10 comprises a housing 14 including a handle 16. A front handle bar 18 is mounted on the housing 14, as is a guide bar 20. A saw chain 22 is supported for movement around the periphery of the guide bar 20 under the action of an engine 24.

As is best shown in FIG. 2, the engine 24 of the chain saw 10 comprises a piston 26 mounted for reciproca tion in a cylinder 28 having a downwardly and rearwardly extending axis 30. A connecting rod 32 connects the' piston 26 to a crankshaft 34 mounted for rotation in a crankcase 36. Thus, upon reciprocation of the piston 26, the crankshaft 34 is rotated about an axis Referring to FIG. 1, the crankshaft 34 of the chain saw 10 is coupled to the saw chain 22 through a clutch v '40 and a sprocket 42. The clutch 40 is adapted for actuation by a trigger 44 mounted in the handle 16, as shown in FIG. 2. Thus, upon actuation of the trigger 44, the sprocket 42 is operatively connected to the crankshaft 34 through the clutch 40, whereby the saw chain 22 is driven by the engine 24 around the periphery of the guide bar 20 to effect cutting.

The engine 24 of the chain saw comprises a two cycle engine. As is usual in such devices, the crankcase 36 of the engine 24 is utilized for induction and precompression of the fuel/air mixture for the engine. Thus, during the compression stroke of the piston 26, a partial vacuum is established in the crankcase 36, whereby a carbureted mixture of air and liquid fuel having a lubricant mixed therewith is drawn into the crankcase 36. During the subsequent power stroke of the piston 26, the fuel/air mixture is compressed in-the crankcase 36. Thus, when the intake valve of the engine 24 is opened, the compressed fuel/air mixture flows rapidly from the crankcase 36 into the portion of the cylinder 28 beyond the piston 26. By this means there is assured a full charge of the fuel/air mixture in the cylinder 28 prior to the compression stroke of the piston 26.

The crankcase 36 of the engine 24 of the chain saw 10 is defined by a pair of

mating die castings

46 and 48. The

die castings

46 and 48 also define an oil reservoir 50 which receives a quantity of oil 52 suitable for lubricating the saw chain 22, such as a light machine oil. In the operation of the chain saw 10, the chain oiling system 12 functions to deliver oil from the reservoir 50 to an oil outlet 56 extending to a slot 58 formed in the "guide bar. By this means oil iscontinuously applied to the chain 22 of the chain saw 10, whereby the chain is lubricated.

The chain oiling system 12 includes an inlet passage way 60comprising a flexible tube 62 extending through the oil reservoir 50 to an inlet 64 comprising a weight 66 and'a screen 68. The weight 66 functions to maintain proper positioning of the inlet end 64 of the tube 62 within the reservoir 50, and the screen'68 functions to prevent foreign matter from entering the chain oiling system 12. As is best shown in FIG. 1, the opposite end of the tube 6 2 is provided with.a fitting 70 mounted in an aperture 72 formed in the pump housing 74.

The operating components of the chain oiling system 12 are located in a pump housing 74 which is detachably secured to the die casting 46 by means of a pair of

screws

76 and 78. The construction and operation of the operating components of the chain oiling system 12 will be best understood by referring to FIG. 5. It should be understood, however, that FIG. 5 is a schematic view in that the component parts of the chain oiling system have been rearranged therein for clarity of illustration. On the other'hand, the functional relationship between the component parts of the chain oiling system 12 are consistent between FIG. 5 and the actual construction of the system. v

The inlet passageway 60 extends to an inlet check valve 80 mounted within the fitting 70. The check valve 80 extends to an oil passageway 82 formed in the pump housing 74. Portions of the oil passageway 82 are common to portions of an upstream pumping cylinder 84 and a downstream pumping cylinder 86. The downstream pumping cylinder 86 is formed in a-barrel 88 which is mounted in the bore 90 formedin the pump housing 74.

The barrel 88 further comprises a circumferential groove 92 and at least one radially extending hole, 94,.

whereby oil flowing through the passageway 82 is received in the downstream pumping cylinder 86. An

outlet check valve 96 is mounted in the lower end of a circumferential groove 100. The groove 100 extends to an oil outlet passageway 102.

Referring momentarily to FIGS. 1, 2 and 4, the oil outlet passageway 102 of the chain oiling system 12 comprises a fitting 104 which functions to secure one end of a flexible conduit l06'to the pump housing 74. A similar fitting 108 is utilized to secure the opposite end of the conduit 106 to the housing 14 of the chain saw 10. By this means oil passing through the chain oiling system 12 is directed to the outlet 56 and into the slot 58, whereby the saw chain 22 is lubricated.

Returning again to FIG. 5, a piston 110 is supported for reciprocation in the downstream pumping cylinder 86. A diaphragm chamber 112 is formed in the pump housing 74 and extends into communication with the downstream pumping cylinder 86. A flexible diaphragm 114 extends through the diaphragm chamber 112. A pair of

opposed plates

116 and 118 are mounted on opposite sides of the diaphragm 114 and function to common to the downstream pumping cylinder 86 is opened to permit the passage of oil therethrough'.

A passageway 122 extends from the crankcase 36 of the engine 24 of the chain saw 10 into the pump housing 74. The passageway 122 includes a portion 124 having a relatively large cross-sectional'area'which extends to' the portion of the diaphragm chamber 112 on the oppoiste side of the diaphragm 114 from the spring 120. By this means positive and negative pressure" pulses which are generated in the crankcase 36 due to the reciprocation of the piston 26 of the engine 24 act on the diaphragm 114 and thereby function to reciprocate the piston 110 into the portion of the downstream pumping cylinder 86 which is common to the oil passageway 82. By this means oil is forced out of the pumping cylinder 86 through the outlet check valve 96 and through the discharge passageway 102"to the slot 58, whereby the oil isavailable for lubrication of the saw chain 22. I

The passageway 122 extending from the crankcase 36 further includes a portion 126 which is substantially smaller in cross-sectional area than the portion 124. The purpose of the passageway 126 is to equalize the pressure on the opposite side of the diaphragm chamber 112, thereby facilitating outward reciprocation of the piston 110 .under the combined action of negative pulses and of the spring 120. It has been found that superior operating results are accomplished in the chain oiling system 12 when the passageway 126 is utilized.

A piston 130 is supported for reciprocation in the upstream pumping cylinder 84.. The piston 130 includes a packing member 132 and is normally positioned as shown in FIG. 5 by a spring 134. By this means the portion of the oil passageway 82 which is common to the upstream pumpingcylinder 84 is normally open to permit the passage of oil therethrough under the action of the piston 110. i

The piston 130 is adapted for manual actuation. Thus, an actuator 136 extends from the piston 130 through a seal 138 to a pushbutton 140. As is best shown in FIG. 2, the pushbutton 140 protrudes from the top of the handle 16 of the housing 14 of the chain saw 10. By this means the pushbutton 140 is adapted for actuation by the thumb of the hand of an operator which engages the handle 16 and having a finger engaging the trigger 44.

The manually actuated piston 130 serves three functions in the chain oiling system 12. First, although the piston 110 is self-priming, the automatic pump of the chain oiling system may be primed more rapidly by using the manual pump.

Second, the piston 110 is reciprocated continuously and very rapidly during the operation of the chain saw 10. This means that the piston 110 and the downstream pumping cylinder 86 must be small in diameter in order to maintain the volume of oil flow from the reservoir 50 to the slot 58 within reasonable limits. By the same token, the small size of the piston and the cylinder 86 means that the cylinder 86 is easily clogged by foreign matter. In such a case the manual pump of the chain oiling system may be utilized to force a substantial volume of oil through the automatic pump, whereby any foreign materials which may have accumulated in the downstream. pumping cylinder are purged therefrom.

Finally, it will be understood that no adjustments are provided in the chain oiling system 12 for controlling the volume of oil flow under the action of the automatic pump. Instead it is deemed preferable to preadjust the automatic pump to supply that quantity of oil which is required to lubricate the chain 22 under normal operating circumstances. Then, in those instances in which additional oil is required in order to properly lubricate the saw chain, the manual pump of the chain oiling system is periodically actuated to furnish the necessary additional oil.

The various structural details of the chain oiling system 12 will be best understood by referring to FIG. 3. Oil is received in the pump housing 74 from the fitting 70 of the inlet passageway 60 through a gasket 142 and an inlet port formed on the same side of the housing as the inlet port of the passageway 122. The upstream pumping cylinder 84 extends perpendicularly with respect to the downstream pumping cylinder 86. This positions the piston 130 for actuation by the pushbutton 140 operating through the actuator 136. The small portion 126 of the passageway 122 comprises a slot formed in the pump housing 74.

The diaphragm chamber 112 of the chain oiling systern 12 is defined by the pump housing 74 and a cap 144 which is secured to the pump housing 74 by the screw 78 and a screw 146. A gasket 148 is provided between the diaphragm 114 and the pump housing 12. The passageway 122 includes

apertures

150 and 152 extending through the gasket 148 and the diaphragm 114.

One of the important advantages resulting from the use of the present invention will now be more easily understood. The entire inlet passageway 60 is positioned beneath the surface of the quantity of oil 52 and the reservoir 50. This completely prevents leakage of air into any portion of the inlet passageway. All of the operating components of the chain saw oiling system 12 are mounted within the pump housing 74. Thus, any leakage of air into these components must occur through the seal 138, the gasket 142 or the gasket 148. Such leaks are therefore easily isolated and corrected. Also, should it prove impossible to correct any such leak, the entire pump housing 174 and the component parts mounted therein may be removed by removing the

screws

76 and 78. By this means all of the operating components of the chain saw oiling syste m may be replaced without disturbing any of the components of the chain saw 10 per se. i

Although particular embodiments of the inventio have been illustrated in the accompanying drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limitedto the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions of parts and elements without departing from the spirit of the invention.

What is claimed is:

1. in a chain saw of the type including a saw chain and an engine for driving the saw chain and having a crankcase for the induction and precompression of a fuel/air mixture, an automatic chain oiler. comprising:

a pump housing including an oil passageway, a pumping cylinder including a portion common to a portion of the oil passageway, and a diaphragm chamber communicating with the pumping cylinder;

inlet and outletcheck valve means mounted at the opposite ends of the oil passageway;

a piston mounted in the pumping cylinder for reciprocation in the cylinder to pump oil through the oil passageway;

a diaphragm mounted in the diaphragm chanber and connected to the piston;

means for admitting pressure pulses from the crankcase of the engine to a first side of the diaphragm in the diaphragm chamber thereby actuating the diaphragm to reciprocate the piston in the pumping cylinder; and

means for relieving pressure from a side of the diaphragm opposite the first side to assist the diaphragm to reciprocate the piston in the cylinder,

said piston being mounted on the diaphragm to respond directly to the pressure pulses by reciprocating through a pumping cycle with each pressure pulse admitted to the diaphragm.

2. A chain saw oiler comprising:

a pump housing detachably secured to a chain saw and including an oil passageway extending from one end of the housing to the other, an upstream pumping cylinder having a portion of the oil pas sageway extending through it, a downstream pumping cylinder having a portion of the oil passageway extending through it, and a diaphragm chamber communicating with the downstream pumpimg cylinder;

inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the pump housing;

a piston mounted in the upstream pumping cylinder for manual reciprocation to pump oil through the oil passageway including the portions extending through the upstream and downstream pumping cylinders;

a piston supported for reciprocation in the downstream pumping cylinder to force oil through the oil passageway;

a diaphragm mounted in the diaphragm chamber and connected to the downstream piston; and

means for admitting pressure pulses from the chain saw to a first side of the diaphragm in the diaphragm chamber and for relieving pressure from a side of the diaphragm opposite the first side thereby actuating the diaphragm to reciprocate the downstream piston whenever the chain saw is operating, said piston being mounted on the diaphragm to respond directly to the pressure pulses by reciprocating through a pumping cycle for each pressure pulse introduced to the diaphragm.

3. The chain saw oiler according to claim 2 further including:

an oil reservoir mounted on the chain saw;

an oil inlet passageway extending from the reservoir to the inlet check valve means; and

an oil outlet passageway extending from the outlet check valve means to the chain of the chain saw, said outlet check valve means including a check valve in the portion of the oil passageway extending through the downstream pumping cylinder for admitting oil to the oil outlet passageway with each reciprocation of the pistons in the upstream and downstream pumping cylinders.

4 In a chain saw of the type including a saw chain and a two-cycle engine for driving the saw chain and having a crankcase for induction and precompression of a fuel/air mixture, a chain oiler comprising;

an oil reservoir;

an oil inlet passageway including I a weighted, screened inlet port positioned in the oil reservoir and a flexible conduit extending from the inlet port to an inlet check valve;

a pump housing detachably secured to the chain saw and including means for receiving oil from the inlet passageway through the inlet check valve;

an oil passageway extending through the pump housmg; a

a'pair of pumping cylinders formed in the pump housing and each including a portion of the oil passageway whereby oil flowing through the oil passageway flows through portions of both of the pumping cylinders in series;

a piston mounted in the upstream oil passageway for reciprocation into and out of the portion of the upstream pumping cylinder common to the oil passageway to pump oil through the passageway;

a piston mounted in the downstream pumping cylinder for reciprocation into andv out of the portion of the downstream pumping cylinder common to the oil passageway to pump oil through the passage-' way;

spring means for normally reciprocating the downstream piston out of the portion of the downstream pumping cylinder.common to the oil passageway and thereby permitting the flow of oil through the pump housing under the action of the upstream piston;

a diaphragm chamber formed in the pump housing and communicating with the downstream pumping cylinder;

a diaphragm mounted in the diaphragm chamber and I outlet check valve means mounted on the pump housing at the opposite end of the oil passageway from the inlet check valve; and I an outlet passageway comprising a conduit extending from the outlet check valve means to a point adjacent the path of travel of the saw chain.

5. The chain oiler according to claim 4 wherein the downstream piston is operated substantially continuously by pressure pulses from the crankcase of the engine to pump lubricating oil from the oil reservoir to the saw chain in sufficient quantity to properly lubricate the saw chain under normal operating circumstances, and wherein the upstream piston comprises a relatively large piston adapted for manual operation to prime the downstream pumping cylinder, to purge foreign matter out of the downstream pumping cylinder and to pump additional oil from the reservoir to a saw chain in those instances in which the quantity of oil pumped by the downstream piston is insufficient to properly lubricate the chain.

6. In a chain saw of the type including a saw chain and an internal combustion engine driving the chain and having a crankcase for induction and precompression of the fuel mixture, the improvement comprising:

a. a pump housing having first and second cylinders, an oil passageway formed through the housing and through the cylinders formed therein and inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the housing;

b. a first pump comprising:

a piston mounted for reciprocation in said first cylinder driven by pressure pulses in the crankcase of the engine for continuously pumping oil from an oil reservoir to the saw chain and thereby lubricating the chain,

a diaphragm-chamber formed in the pump housing and communicating with the pumping cylinder of the first pump,

a diaphragm mounted in the diaphragm chamber and connected to the piston of the first pump, and

means for admitting pressure pulses from the crankcase of the engine to the diaphragm chamher and thereby reciprocating the piston of the first pump in its pumping cylinder;

0. a second pump having a piston mounted for reciprocation in said second cylinder, said second pump being located between the oil reservoir and the first pump in flow communication with the oil passageway, and being manually actuated for priming the first pump, for purging foreign matter out of the first pump, and for pumping additional oil to the chain whenever the oil from the first chain pump is insufficient to properly lubricate the chain;

d. a spring positioned between the diaphragm and the pump housing and thereby biasing the piston of the first pump for reciprocation out of the oil passageway to permit the flow of oil therethrough;

e. a major passageway extending through the pump housing to the side of the diaphragm opposite the spring whereby the diaphragm is responsive to positive pressure pulses in the crankcase to reciprocate the piston into the oil passageway to accomplish a pumping stroke; and I f. a minor passageway extending from the crankcase to the same side of the diaphragm as the spring whereby pressure in the diaphragm chamber is relieved.

7. In a chain saw of the type including a saw chain and an engine for driving the saw chain and having a crankcase for the induction and precompression of a fuel/air mixture, an automatic chain oiler comprising:

inlet and outlet check valve means mounted at the opposite ends of the oil passageway;

a piston mounted in the pumping cylinder for reciprocation into and out of the portion of the cylinder common to the oil passageway to pump oil through the oil passageway;

a diaphragm mounted in the diaphragm chamber and connected to the piston;

a spring positioned in the diaphragm chamber for reciprocating the piston out of the portion of the pumping cylinder common to the oil passageway and thereby permitting oil through the passageway; and

means for admitting pressure pulses from the crankcase to the diaphragm chamber comprising a first relatively large passageway formed in the pump housing for directing pressure pulses from the crankcase to the opposite side of the diaphragm from the spring whereby positive pressure pulses in the crankcase acting against the diaphragm reciprocate the piston into the portion of the pumping cylinder common to the oil passageway against the action of the spring, and a second relatively small passageway formed in the housing and extending to the same side of the diaphragm as the spring for relieving pressure in the diaphragm chamber.

8. The chain oiler according to claim 7 further including:

a second pumping cylinder formed in the pump housing and including a portion common to a portion of the oil passageway, and

a second piston mounted in the second pumping cylinder for manual reciprocation to force oil through the oil passageway including that portion common to the first pumping cylinder and thereby priming the first cylinder, clearing foreign matter from the first pumping cylinder, and supplying quantities of oil to the chain in excess of those supplied by the operation of the first pump.

9. The chain oiler according to claim 8 further including:

an oil reservoir mounted on the chain saw;

a flexible oil conduit extending from an inlet in the oil reservoir to the inlet check valve means; and an oil outlet conduit extending from the outlet check valve means to the saw chain.

10. In a chain saw of the type including a saw chain and an internal combustion engine driving the chain and having a crankcase for induction and precompression of the fuel mixture, the improvement comprising:

a pump housing having first and second cylinders and an oil passageway formed through the pump housing between the cylinders and in communication with an oil reservoir and the saw chain,

a first pump having a piston inthe first cylinder mounted to reciprocate in the first cylinder in response to cyclical pressure pulses in the crankcase of the engine to continuously pump oil from the oil reservoir to the saw chain and thereby lubricate the chain, and

a second pump having a piston mounted for manual reciprocation in the second cylinder located be tween the oil reservoir and the first pump in flow communication with the oil passageway, said second pump being selectively actuated to pump oil through the oil passageway and the first cylinder for priming the first pump, for purging foreign matter out of the first pump, and for pumping additional oil to the chain whenever the oil from the first pump is insufficient to properly lubricate the chain. 7 11. The improvement according to claim and further including inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the housing for passing oil through the oil passageway with each reciprocation of said first and second pumps. 12. The improvement according to claim 11 wherein the first pump comprises:

a diaphragm chamber formed in the pump housing 25 and communicating with the first cylinder of the first pump; a diaphragm mounted in the diaphragm chamber, the

piston of the firstpump being mounted on the diaphragm for reciprocation in the first cylinder; and means for admitting pressure pulses from the crankcase of the engine to the diaphragm chamber and thereby reciprocating the piston of the first pump in its pumping cylinder through a pumping cycle phragm chamber.

13. In a chain saw of the type including a saw chain and an internal combustion engine driving the chain and having a crankcase for induction and precompression of thefuel mixture, the improvement comprising:

a pump housing having first and second cylinders, an

' oil passageway formed between the cylinders, and a pressure passageway in communication with the engine crankcase, diaphragm mounted in the pressure passageway and reciprocally moveable in response to cyclical pressure pulses transmitted to the diaphragm from the crankcase,

a first piston in the first cylinder mounted on the diaphragm for reciprocation in the first cylinder through a pumping cycle for each of the cyclical pressure pulses transmitted to the diaphragm for continuously pumping oil from an oil reservoir to the saw chain and thereby lubricating the chain, and

a second piston mounted for manual reciprocation in r with each pressure pulse admitted to the dia- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent ,865,213 Dated Februarv 11, 1975 Inven John W. McDermott It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column ne 27, delete "chanber" and sub i therefor --chamber-;

Column 8, line 3h, delete "chain" second occurrence Signed and sealed this 5th day of April 1.975.

(SEAL) Attest:

C MARSHALL DAI-ZI'I RUTH C. 'L TSON Commissioner of Patents Arresting Officer I and Trademarks l FORM PO-10 0 (10-69) uscoMM-Dc cove-Poo i U. S. GOVIIIIIIIIT PRINTING OFFICE Ill, O-lOC-SJ.

Claims

1. In a chain saw of the type including a saw chain and an engine for driving the saw chain and having a crankcase for the induction and precompression of a fuel/air mixture, an automatic chain oiler comprising: a pump housing including an oil passageway, a pumping cylinder including a portion common to a portion of the oil passageway, and a diaphragm chamber communicating with the pumping cylinder; inlet and outlet check valve means mounted at the opposite ends of the oil passageway; a piston mounted in the pumping cylinder for reciprocation in the cylinder to pump oil through the oil passageway; a diaphragm mounted in the diaphragm chanber and connected to the piston; means for admitting pressure pulses from the crankcase of the engine to a first side of the diaphragm in the diaphragm chamber thereby actuating the diaphragm to reciprocate the piston in the pumping cylinder; and means for relieving pressure from a side of the diaphragm opposite the first side to assist the diaphragm to reciprocate the piston in the cylinder, said piston being mounted on the diaphragm to respond directly to the pressure puLses by reciprocating through a pumping cycle with each pressure pulse admitted to the diaphragm.

2. A chain saw oiler comprising: a pump housing detachably secured to a chain saw and including an oil passageway extending from one end of the housing to the other, an upstream pumping cylinder having a portion of the oil passageway extending through it, a downstream pumping cylinder having a portion of the oil passageway extending through it, and a diaphragm chamber communicating with the downstream pumpimg cylinder; inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the pump housing; a piston mounted in the upstream pumping cylinder for manual reciprocation to pump oil through the oil passageway including the portions extending through the upstream and downstream pumping cylinders; a piston supported for reciprocation in the downstream pumping cylinder to force oil through the oil passageway; a diaphragm mounted in the diaphragm chamber and connected to the downstream piston; and means for admitting pressure pulses from the chain saw to a first side of the diaphragm in the diaphragm chamber and for relieving pressure from a side of the diaphragm opposite the first side thereby actuating the diaphragm to reciprocate the downstream piston whenever the chain saw is operating, said piston being mounted on the diaphragm to respond directly to the pressure pulses by reciprocating through a pumping cycle for each pressure pulse introduced to the diaphragm.

3. The chain saw oiler according to claim 2 further including: an oil reservoir mounted on the chain saw; an oil inlet passageway extending from the reservoir to the inlet check valve means; and an oil outlet passageway extending from the outlet check valve means to the chain of the chain saw, said outlet check valve means including a check valve in the portion of the oil passageway extending through the downstream pumping cylinder for admitting oil to the oil outlet passageway with each reciprocation of the pistons in the upstream and downstream pumping cylinders.

4. In a chain saw of the type including a saw chain and a two-cycle engine for driving the saw chain and having a crankcase for induction and precompression of a fuel/air mixture, a chain oiler comprising: an oil reservoir; an oil inlet passageway including a weighted, screened inlet port positioned in the oil reservoir and a flexible conduit extending from the inlet port to an inlet check valve; a pump housing detachably secured to the chain saw and including means for receiving oil from the inlet passageway through the inlet check valve; an oil passageway extending through the pump housing; a pair of pumping cylinders formed in the pump housing and each including a portion of the oil passageway whereby oil flowing through the oil passageway flows through portions of both of the pumping cylinders in series; a piston mounted in the upstream oil passageway for reciprocation into and out of the portion of the upstream pumping cylinder common to the oil passageway to pump oil through the passageway; a piston mounted in the downstream pumping cylinder for reciprocation into and out of the portion of the downstream pumping cylinder common to the oil passageway to pump oil through the passageway; spring means for normally reciprocating the downstream piston out of the portion of the downstream pumping cylinder common to the oil passageway and thereby permitting the flow of oil through the pump housing under the action of the upstream piston; a diaphragm chamber formed in the pump housing and communicating with the downstream pumping cylinder; a diaphragm mounted in the diaphragm chamber and connected to the downstream piston; relatively large conduit means extending from the crankcase of the engine to one side of the diaphragm for applying pressure pulses from the crankcase to the diaphragm and thereby reciprocating the pistOn of the downstream pump against the action of the spring means; relatively small conduit means extending from the crankcase to the opposite side of the diaphragm for relieving pressure in the diaphragm chamber; outlet check valve means mounted on the pump housing at the opposite end of the oil passageway from the inlet check valve; and an outlet passageway comprising a conduit extending from the outlet check valve means to a point adjacent the path of travel of the saw chain.

6. In a chain saw of the type including a saw chain and an internal combustion engine driving the chain and having a crankcase for induction and precompression of the fuel mixture, the improvement comprising: a. a pump housing having first and second cylinders, an oil passageway formed through the housing and through the cylinders formed therein and inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the housing; b. a first pump comprising: a piston mounted for reciprocation in said first cylinder driven by pressure pulses in the crankcase of the engine for continuously pumping oil from an oil reservoir to the saw chain and thereby lubricating the chain, a diaphragm chamber formed in the pump housing and communicating with the pumping cylinder of the first pump, a diaphragm mounted in the diaphragm chamber and connected to the piston of the first pump, and means for admitting pressure pulses from the crankcase of the engine to the diaphragm chamber and thereby reciprocating the piston of the first pump in its pumping cylinder; c. a second pump having a piston mounted for reciprocation in said second cylinder, said second pump being located between the oil reservoir and the first pump in flow communication with the oil passageway, and being manually actuated for priming the first pump, for purging foreign matter out of the first pump, and for pumping additional oil to the chain whenever the oil from the first chain pump is insufficient to properly lubricate the chain; d. a spring positioned between the diaphragm and the pump housing and thereby biasing the piston of the first pump for reciprocation out of the oil passageway to permit the flow of oil therethrough; e. a major passageway extending through the pump housing to the side of the diaphragm opposite the spring whereby the diaphragm is responsive to positive pressure pulses in the crankcase to reciprocate the piston into the oil passageway to accomplish a pumping stroke; and f. a minor passageway extending from the crankcase to the same side of the diaphragm as the spring whereby pressure in the diaphragm chamber is relieved.

7. In a chain saw of the type including a saw chain and an engine for driving the saw chain and having a crankcase for the induction and precompression of a fuel/air mixture, an automatic chain oiler comprising: a pump housing including an oil passageway, a pumping cylinder including a portion common to a portion of the oil passageway, and a diaphragm chamber communicating with the pumping cylinder; inlet and outlet check valve means mounted at the opposite ends of the oil passageway; a piston mounted in the pumping cylinder for reciprocation into and out of the portion of the cylinder common tO the oil passageway to pump oil through the oil passageway; a diaphragm mounted in the diaphragm chamber and connected to the piston; a spring positioned in the diaphragm chamber for reciprocating the piston out of the portion of the pumping cylinder common to the oil passageway and thereby permitting oil through the passageway; and means for admitting pressure pulses from the crankcase to the diaphragm chamber comprising a first relatively large passageway formed in the pump housing for directing pressure pulses from the crankcase to the opposite side of the diaphragm from the spring whereby positive pressure pulses in the crankcase acting against the diaphragm reciprocate the piston into the portion of the pumping cylinder common to the oil passageway against the action of the spring, and a second relatively small passageway formed in the housing and extending to the same side of the diaphragm as the spring for relieving pressure in the diaphragm chamber.

8. The chain oiler according to claim 7 further including: a second pumping cylinder formed in the pump housing and including a portion common to a portion of the oil passageway, and a second piston mounted in the second pumping cylinder for manual reciprocation to force oil through the oil passageway including that portion common to the first pumping cylinder and thereby priming the first cylinder, clearing foreign matter from the first pumping cylinder, and supplying quantities of oil to the chain in excess of those supplied by the operation of the first pump.

9. The chain oiler according to claim 8 further including: an oil reservoir mounted on the chain saw; a flexible oil conduit extending from an inlet in the oil reservoir to the inlet check valve means; and an oil outlet conduit extending from the outlet check valve means to the saw chain.

10. In a chain saw of the type including a saw chain and an internal combustion engine driving the chain and having a crankcase for induction and precompression of the fuel mixture, the improvement comprising: a pump housing having first and second cylinders and an oil passageway formed through the pump housing between the cylinders and in communication with an oil reservoir and the saw chain, a first pump having a piston in the first cylinder mounted to reciprocate in the first cylinder in response to cyclical pressure pulses in the crankcase of the engine to continuously pump oil from the oil reservoir to the saw chain and thereby lubricate the chain, and a second pump having a piston mounted for manual reciprocation in the second cylinder located between the oil reservoir and the first pump in flow communication with the oil passageway, said second pump being selectively actuated to pump oil through the oil passageway and the first cylinder for priming the first pump, for purging foreign matter out of the first pump, and for pumping additional oil to the chain whenever the oil from the first pump is insufficient to properly lubricate the chain.

11. The improvement according to claim 10 and further including inlet and outlet check valve means mounted at the opposite ends of the oil passageway of the housing for passing oil through the oil passageway with each reciprocation of said first and second pumps.

12. The improvement according to claim 11 wherein the first pump comprises: a diaphragm chamber formed in the pump housing and communicating with the first cylinder of the first pump; a diaphragm mounted in the diaphragm chamber, the piston of the first pump being mounted on the diaphragm for reciprocation in the first cylinder; and means for admitting pressure pulses from the crankcase of the engine to the diaphragm chamber and thereby reciprocating the piston of the first pump in its pumping cylinder through a pumping cycle with each pressure pulse admitted to the diaphragm chamber.

13. In a chain saw of the type including a saw chain and an internal combustion engine driving the cHain and having a crankcase for induction and precompression of the fuel mixture, the improvement comprising: a pump housing having first and second cylinders, an oil passageway formed between the cylinders, and a pressure passageway in communication with the engine crankcase, a diaphragm mounted in the pressure passageway and reciprocally moveable in response to cyclical pressure pulses transmitted to the diaphragm from the crankcase, a first piston in the first cylinder mounted on the diaphragm for reciprocation in the first cylinder through a pumping cycle for each of the cyclical pressure pulses transmitted to the diaphragm for continuously pumping oil from an oil reservoir to the saw chain and thereby lubricating the chain, and a second piston mounted for manual reciprocation in the second cylinder in flow communication with the oil passageway and located upstream from the first piston to pump oil through the oil passageway and the first cylinder for manually priming the first pump, purging foreign matter out of the first pump, and pumping additional oil to the chain whenever the oil from the first pump is insufficient to properly lubricate the chain.