Portable chain saw attachment in the form of fluid pump apparatus

Abstract

 An attachment (2) for a chain saw power head (1) said attachment having a fluted driven sprocket (11) supported by a housing defining an endless track to receive a chain (9) to be driven by said power head, a pump (12) attached to said housing and driven by said sprocket (11) and wherein the pump (12) has a self supporting nozzle 15 directable by movement of the power head (1).

Description

[0001] The present invention relates to portable fluid pump apparatus and more particularly but not exclusively to a fluid pump attachment for a chain saw engine or other portable hand-held internal combustion engine.

[0002] It is known to have attachments for chain saw engines in which the blade and cutting chain of the chain saw are removed and an attachment, such as a rotary drill, is secured to the chain saw engine by means of a member having a shape similar to that of a chain saw blade. A chain driven by the output of the engine is then used to drive the attachment. Known such arrangements are shown in U.S. Patents 2,810,409, 3,580,342 and 2,783,794.

[0003] It is also known to have internal combustion engines driving pumps, and in particular liquid pumps, the output of the pump being passed through a flexible hose or conduit to a spray nozzle. For example see U.S. Patents 3,320,895, 2,737,340, 3,018,927, 3,857,515. Although such engine and pump combinations have hitherto been portable in the sense that they were able to be carried from place to place, they were only able to be operated with the engine, pump and their mounting frame supported by the ground or some supporting platform such as the tray of a truck.

[0004] It is further known to attach pumps to electrical hand drills as shown in U.S. Patent 3,059,583. However, such arrangements are not only very restricted in their portable use and capacity, but also cannot be used at all where there is no electricity supply.

[0005] Finally, it is also known to have portable spray misting apparatus for use in spraying insecticides and other chemicals on orchard trees and other plants. Such apparatus typically comprises a back pack which includes a tank and small internal combustion engine mounted together and arranged to be carried on the back of an operator. The pump is directly connected to the output shaft of the small internal combustion engine, the bearings of which support the pump rotor. The output of the pump is connected to a spray nozzle via a flexible conduit. The operator carries the apparatus on his back and directs the spray by altering the direction in which the nozzle is pointed. Irrespective of the direction of spray, the engine remains in substantially the same position.

[0006] It is the object of the present invention to overcome some of the disadvantages of the abovementioned prior art apparatus and to provide apparatus which is of lower cost than hitherto, and is more flexible in terms of the uses to which the apparatus may be put.

[0007] There is disclosed herein a portable attachment for a chain saw having an internal combustion engine and a drive sprocket, said attachment comprising a housing defining an endless track to receive and guide a driven chain in its movement along a predetermined path, a driven sprocket rotatably attached to the housing at one end and extending into said path for power transmitting engagement with said chain so as to be driven thereby, fluid pump means secured to said housing and attached to said driven sprocket so as to be driven thereby, said housing being adapted at the other end to said one end to be fixed to said engine so that said drive sprocket extends into said path for power transmitting engagement with said chain so as to drive same, and wherein said pump has a fluid inlet for connection to a fluid reservoir and a nozzle outlet, said nozzle being self supporting and directable by movement of the engine by an operator.

[0008] The attachment described in the above paragraph has the distinct advantage in that.when in use the pump, by being fixed to the power plant of a chain saw, is supported by the user gripping the hand grips of the chain saw thus the output nozzle of the pump is directable by movement of the hand grips. A further advantage is that it is totally portable while in use.

[0009] Additionally, sprockets used with chain saws are illustrated in U.S. Patents 3,786,687, 3,868,863, 3,962,929 and 3,279,272. These sprockets are of the flute type described herein. However, they are either part of, self aligning or fixed to a clutch drum and/or hub which is freely rotatable on the engine output shaft so that it is possible for the engine shaft to turn at a different speed to that of the sprocket. Still further the prior art sprockets, as in _U.S. Patents 3,786,687 and 3,868,863 are not rigidly connected to the output shaft while the alternate deformations on one side of the discs are fixed to the output plate of the clutch drum thereby closing off alternate depressions in the edge of the disc. Thus the teeth which engage within these openings are prevented by the sprocket arrangement from sideways movement towards either one or both sides. With particular reference to U.S. Patent 3,962,929 there is described a free floating and self aligning and again freely rotatable sprocket. Still further the flute of these known sprockets are box like flute structures which allow lateral movement of the saw chain.

[0010] It is an object of a further aspect of the present invention to overcome or substantially ameliorate the problems associated with the above described known sprockets.

[0011] There is disclosed herein a butterfly sprocket to be driven by a chain and to be rigidly connected to a shaft to be driven by the chain via said sprocket, said sprocket being of a general disc-shaped formed from sheet metal with alternate radially extending undulating wave type troughs and peaks which are spaced angularly around the disc so that the disc has portions spaced alternately on different sides. of the plane of the discs so as to form the troughs to drivingly receive portions of the chain.

[0012] Preferred embodiments of the present invention will now be described with reference to the drawings in which:

- Fig. 1 is an edge elevation of the butterfly sprocket of the preferred embodiment,

Fig. 2 is an exploded perspective view of a chain saw engine equipped with a liquid pump attachment,

Fig. 3 is a perspective view of a gas blast attachment suitable for pumping gases such as air,

Fig. 4 is a perspective view of a liquid high pressure pump attachment,

Fig. 5 is a perspective view of a centrifugal or vane operated fluid pump attachment, and

Fig. 6 is a perspective view of a piston operated fluid pump attachment.

[0013] Referring now to the drawings, Fig. 2 illustrates a liquid pump attachment of the preferred embodiment which is suitable for operation from a small portable hand held internal combustion engine which preferably comprises chain saw engine 1. The liquid pump attachment 2 comprises a blade 3 which is securable to the chain saw engine 1 by means of bolts 4, nuts 5, and tensioning lug 6. The bolts 5 and lug 6 pass through a T-shaped slot 7 in the blade 3.

[0014] The blade 3 has two grooves 8, only the upper groove 8 being illustrated, which form a track for a transmission chain 9 having interior driving teeth 17. The transmission chain 9 is driven by a conventional chain saw sprocket arrangement 10 which is directly connected to the output of a centrifugal clutch (not illustrated) which comprises part of the chain saw engine 1. The chain 9 passes over butterfly sprocket 11 which is rigidly connected to one end of a shaft (not illustrated) rotatably mounted in the pump assembly 2. Thus the sprocket 11 is not rotatable relative to the shaft. This shaft comprises the driven shaft of a liquid pump 12. The outlet 13 of the pump 12 is connected via a rigid conduit 14 to a nozzle 15. A cover plate 16 provides protection from the moving chain 9 for the operator.

[0015] In operation, with the attachment 2 connected to the chain saw engine 1, the inlet (not illustrated) of the liquid pump 12 is connected by means of a flexible hose (not illustrated) to a suitable reservoir of liquid (not illustrated). With the chain saw engine 1 operating, it is only necessary for the engine revolutions to be increased above idle speed and the centrifugal clutch of the engine 1 engages, thereby rotating the sprocket arrangement 10. As a result, the chain 9 is driven along the grooves 8 so as to rotate the butterfly sprocket 11 thereby operating the pump 12. In consequence, liquid is pumped from the reservoir, through the pump 12, through the rigid conduit 14, and out of the nozzle 15 in the form of a spray.

[0016] Preferably the liquid reservoir comprises a tank adapted to be carried on the back of an operator and therefore the chain saw engine and attachment together with the tank may be used to replace a conventional knapsack spray. Since the chain saw engine is of relatively light weight and is easily manipulated by the operator, not only does this arrangement overcome the need for the operator to manually pump liquid from the reservoir but the liquid is pumped at a much greater rate, and over much greater distances, than hitherto. The direction in which the liquid is sprayed by the nozzle 15 is easily controlled by the operator altering the position and angle at which the chain saw engine 1 is held. This particular embodiment of the present invention finds application in the fighting of bush forest fires, the spraying of crops, weeds and orchards, and similar such applications.

[0017] The butterfly sprocket 11 of Fig. 2 is illustrated in an edge elevation in Fig. 1. From both Figs. 1 and 2 it will be seen that the butterfly sprocket 11 comprises a flat disc having a deformed annular region at its periphery. The edge 20 of the sprocket 11 is formed into an approximately zig-zag shape so as to provide a plurality of angulated regions 21 which are equally spaced from the plane of the disc. Adjacent regions 21 are displaced equally from the plane of the disc but in opposite directions. It will be seen from Figs. 1 and 2 that the interior teeth 17 of the transmission chain 9 are received by the shaped edge 20 of the sprocket 11.

[0018] In chain saw attachments known hitherto, the butterfly sprocket 11 has not been used but rather a sprocket made from two identical spaced parallel discs has been used. The discs are maintained in position by a plurality of small spacers located between the discs at regularly spaced intervals around the peripheries. The opening between each spacer is dimensioned to receive the interior teeth 17 of the. drive chain 9. Such an arrangement is relatively expensive to make since the spacers and discs must be welded or rivet- ted together in order to provide an integral structure of sufficient strength. This disadvantage is overcome in accordance with the present invention since the butterfly sprocket 11 may be stamped in a single operation from a flat sheet of metal.

[0019] Such a sprocket is illustrated in the sprocket arrangement 10 of Fig. 2. However, the deformed disc of this arrangement is not free standing as is the sprocket 11 in Fig. 2.

[0020] The present sprocket 11 provides for only every second one ox the interior teeth 17 being prevented from moving to one particular side by the sprocket 11. The remaining interior teeth 17 are prevented from moving in the opposite direction to the other side by the sprocket 11.

[0021] The sprocket 11 is rigidly fixed to the driven shaft so that it rotates at the same R.P.M. as the shaft always remains fixed in the same plane. Furthermore, the flute like arrangements of the outer diameter of the sprocket 11 are angulated in contrast to the square shaped formations of all the prior art.. This angulated formation locates the transmission chain in a fixed plane with no sideways movement due to the wedge shaped action of the flute arrangement. The zig zag shape of sprocket 11 plus the angulated regions 21 force the transmission chain driving teeth into a laterally fixed position thus providing a secure and lower wearing driven sprocket arrangement.

[0022] The present invention is applicable to all fluids including both liquids and gases, and Figs. 3 to 6 inclusive illustrate embodiments of chain saw attachments having different types of fluid pump. In the embodiment of Fig. 3, the fluid pump comprises a gas blast compressor or similar such centrifugal gas pump and, in use, provides a concentrated blast of gas or air which may be used for cleaning purposes, such as blasting; spraying atomised or misted liquids; and other such applications.

[0023] Figs. 4 to 6 inclusive illustrate liquid pumps of known construction but different operating principles assembled so as to form a chain saw attachment.

[0024] Furthermore, although the conduit 14 of Fig. 2 is described as rigid, in accordance with the present invention, such a conduit may be flexible so long as the nozzle 15 is supported. Thus if the nozzle 15 does not droop excessively, the flexible conduit 14 may be used to spray a relatively broad swathe by reciprocally moving the chain saw engine to and fro in a horizontal plane thereby causing the nozzle 15 to move through a horizontal arc.

[0025] In accordance with the aspect of the present invention relating to portable fluid pump apparatus specified in the last complete paragraph of page 3, it is to be understood that the connection between the fluid pump means and the engine may be direct and/or via a clutch, which may or may not include a gear train, or via a chain drive (as described in detail) or via a belt drive. Thus the fluid pump means can be secured to the output shaft of the engine either directly or via flexible coupling or universal joint.

[0026] One advantage of the present invention is that the operator changes the position and/or angle in which the pump and/or engine is held in order to change the direction in which the nozzle points. Thus the invention embraces portable hand-held pumps to which a small driving engine is connected such that the combination of pump and engine is portable and hand-held.

Claims

1. A portable chain saw attachment for a portable chain saw powerhead having an internal combustion engine and a drive sprocket, said attachment comprising a housing defining an endless tract to receive and guide a driven chain in its movement along a predetermined path, a driven sprocket rotatably attached to the housing at one end and extending into said path for power transmitting engagement with said chain so as to be driven thereby, fluid pump means secured to said housing and attached to said driven sprocket so as to be driven thereby, said housing being adapted at the other end to said one end to be fixed to said engine so that said drive sprocket extends into said path for power transmitting engagement with said chain so as to drive same, and wherein said pump has a fluid inlet for connection to a fluid reservoir and a nozzle outlet, said nozzle outlet being self supporting and directable by movement of the engine by an operator who holds the interconnected attachment and powerhead in his hands during operation.

2. The chain saw attachment of claim 1 wherein said nozzle outlet is connected to said pump by a flexible conduit member.

3. The chain saw attachment of claim 1 wherein said nozzle outlet is connected to said pump by a rigid conduit member.

4. The chain saw attachment of claim 2 or 3 wherein said fluid pump is adapted to pump liquid.

5. The chain saw attachment of claim 2 or 3 wherein said pump is adapted to pump gas.

6. In combination, a portable chain saw powerhead including an internal combustion engine and a drive sprocket and a portable chain saw attachment according to claim 1 releasably secured to said chain saw powerhead.

7. In combination, a portable hand-held internal combustion engine, an attachment secured to said engine for portable operation therewith, said attachment comprising a fluid pump having a fluid inlet for connection to a fluid reservoir and a nozzle outlet, said nozzle outlet being self supporting and directable by movement of the engine by an operator who holds the interconnected attachment and engine in his hands during operation.

8. A chain saw attachment substantially as hereinbefore described with reference to the accompanying drawings.

9. A butterfly sprocket to be driven by a chain and to be rigidly connected to a shaft to be driven by the chain via said sprocket, said sprocket being of a general disc-shaped form from sheet metal with alternate radially extending undulating wave type troughs and peaks which are spaced angularly around the disc so that the disc has portions spaced alternately on different sides of the plane of the discs so as to form the troughs to drivingly receive portions of the chain.

10. The sprocket of claim 9 wherein the troughs are equally spaced from the claim of the disc thus locating the chain in a fixed plane.

11. A butterfly sprocket substantially as hereinbefore described with reference to the accompanying drawings.

Drawing