THERMAL CONTROL FOR COMBUSTION TOOLS

Abstract

A combustion tool (100, 200, 300) comprises an engine (101, 201, 301), a fuel cartridge (102, 202, 302) and a heat transfer means (103, 203, 303) for selectively transferring heat from the engine to the fuel cartridge. Figure for abstract: FIG. 1.

Description

Title of the invention: THERMAL REGULATION FOR COMBUSTION TOOLS Technical field of the invention

[0001] The present invention relates generally to the thermal regulation of one or more components of a combustion tool. More specifically, although not exclusively, the present invention relates to the thermal regulation of a fuel cartridge of a combustion tool. Technical background

[0002] Combustion-powered nail and staple driving tools are known and normally comprise a housing enclosing an internal combustion engine. The engine is powered by a pressurized fuel gas reservoir, also called a fuel canister. Summary of the invention

[0003] The present invention aims to provide a more reliable combustion tool.

[0004] The invention relates to a combustion tool comprising a fuel cartridge and a control means for adjusting the temperature of the fuel cartridge during use.

[0005] When fuel is extracted from the fuel cartridge in use, some of the remaining fuel vaporizes, which reduces the temperature of the fuel in the fuel cartridge. One of the consequences of the reduction in temperature in the cartridge is a consequent drop in the pressure of the cartridge and the fuel it contains.

[0006] The inventors have found that this reduction in pressure can affect the injection system and, in extreme cases, lead to tool failure, if the combustion tool is used continuously for extended periods.

[0007] The invention therefore makes it possible to have a more reliable combustion tool, by regulating the temperature of the fuel cartridge.

[0008] The control means may comprise a heat transfer means. The heat transfer means may be operable to selectively transfer heat from a heat source to the fuel cartridge.

[0009] The invention also relates to a combustion tool comprising a heat source, a fuel cartridge and a heat transfer means for selectively transferring heat from the heat source to the fuel cartridge.

[0010] The heat source may comprise a motor. The motor may be configured to receive fuel from the fuel canister.

[0011] More specifically, the heat source may include an engine configured to receive fuel from the fuel cartridge.

[0012] The regulating means or the heat transfer means may comprise a control device, for example for controlling the heat transfer between the heat source and the fuel cartridge.

[0013] The regulating means, the heat transfer means or the control device may comprise or may operate in a first, connected state, in which heat may be transferred from the heat source to the fuel cartridge. The regulating means, the heat transfer means or the control device may comprise or may operate in a second, disconnected state, in which heat transfer is inhibited between the heat source and the fuel cartridge.

[0014] The regulating means or the heat transfer means may comprise a thermal bridge, for example to provide a conductive path between the engine and the fuel cartridge.

[0015] More specifically, the heat transfer means may comprise a thermal bridge to provide a conductive path between the engine and the fuel cartridge.

[0016] The regulating means, the heat transfer means or the control device may comprise an actuator. The actuator may be for selectively closing and opening the thermal bridge. The actuator may cause the thermal bridge to enter and exit thermal contact with the fuel cartridge or the engine.

[0017] The actuator may move the thermal bridge, for example between a connected position and a disconnected position. A conductive path may be provided between the motor and the fuel cartridge, for example in the connected position. The conductive path may be interrupted, for example in the disconnected position.

[0018] More specifically, the heat transfer means may comprise an actuator that moves the thermal bridge between a connected position, in which a conductive path is provided between the engine and the fuel cartridge, and a disconnected position, in which the conductive path is interrupted.

[0019] The actuator may include a thermal actuator. The thermal actuator may include a material that expands and contracts depending on the temperature of the device. For example, the material may be a liquid, a gas, a wax, or a wax-like substance. The thermal actuator may include a wax thermal actuator.

[0020] The thermal actuator may be configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge reaches a predetermined minimum threshold. The thermal actuator may be configured to move the thermal bridge to the connected position when the fuel cartridge temperature reaches a predetermined maximum threshold.

[0021] More specifically, the actuator may comprise a thermal actuator configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge reaches a predetermined minimum threshold and / or to move the thermal bridge to the connected position when the temperature of the fuel cartridge reaches a predetermined maximum threshold.

[0022] The thermal bridge may include a bimetallic thermal switch. The bimetallic thermal switch may be configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge reaches a predetermined minimum threshold. The bimetallic thermal switch may be configured to move the thermal bridge to the connected position when the temperature of the fuel cartridge reaches a predetermined maximum threshold.

[0023] More specifically, the thermal bridge may comprise a bimetallic thermal switch configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge reaches a predetermined minimum threshold and / or to move the thermal bridge to the connected position when the temperature of the fuel cartridge reaches a predetermined maximum threshold.

[0024] The actuator may comprise a motor, an electromagnet or a solenoid.

[0025] The regulating means, the heat transfer means or the control device may comprise a thermal circuit breaker. The thermal circuit breaker may be configured to connect the motor, the electromagnet or the solenoid to a power source, for example when the temperature of the fuel cartridge reaches a predetermined maximum threshold. The thermal circuit breaker may be configured to disconnect the motor, the electromagnet or the solenoid from the power source, for example when the temperature of the fuel cartridge reaches a predetermined minimum threshold.

[0026] More specifically, the thermal transfer means may comprise a thermal circuit breaker configured to connect the motor, the electromagnet or the solenoid to a power source when the temperature of the fuel cartridge reaches a predetermined maximum threshold and / or to disconnect the motor, the electromagnet or the solenoid from the power source when the temperature of the fuel cartridge reaches a predetermined minimum threshold.

[0027] The regulating means or the heat transfer means may comprise an air circulation means, for example for directing a flow of air heated by the engine towards the fuel cartridge.

[0028] More specifically, the heat transfer means comprises air circulation means for directing a flow of air heated by the engine towards the fuel cartridge.

[0029] The control means, the heat transfer means or the air circulation means may comprise a fan, for example to induce an air flow around and / or through the engine. The control means, the heat transfer means or the air circulation means may comprise a valve, for example to selectively allow air to flow to the fuel cartridge. The valve may be downstream of the engine.

[0030] More specifically, the air circulation means may comprise a fan for inducing airflow around and / or through the engine and a valve downstream of the engine for selectively allowing air to flow to the fuel cartridge.

[0031] The control means, the heat transfer means or the air circulation means may comprise a processor, which may be configured or programmed to control the transfer of heat from the heat source to the fuel cartridge. The processor may be configured or programmed to operate the control device, the actuator, the fan or the valve. The control means, the heat transfer means or the air circulation means may comprise a memory, which may be operatively connected to the processor. The memory may comprise a computer program or computer code enabling the processor to control the transfer of heat from the heat source to the fuel cartridge. The memory may comprise a computer program or computer code enabling the processor to operate the control device, the actuator, the fan or the valve.

[0032] The control means, the heat transfer means or the air circulation means may comprise one or more sensors, for example one or more temperature sensors, which may be operatively connected to the processor. At least one of the sensors may be associated with the fuel cartridge and / or configured to measure the temperature of the fuel cartridge. At least one of the sensors may be associated with the heat source or the engine and / or configured to measure the temperature of the heat source or the engine.

[0033] The processor may be configured or programmed to control the transfer of heat from the heat source to the fuel canister in response to one or more signals received from the one or more sensors. The processor may be configured or programmed to operate the controller, actuator, fan, or valve in response to one or more signals received from the one or more sensors.

[0034] The combustion tool may include a nailer or a stapler.

[0035] For the avoidance of doubt, all features described herein apply equally to any aspect of the invention.

[0036] Within the scope of the present application, it is expressly provided that the various aspects, embodiments, examples and alternatives set forth in paragraphs preceding, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. In other words, all embodiments and / or features of any embodiment may be combined in any way, unless these features are incompatible.

[0037] For the avoidance of doubt, the terms "may", "and / or", "for example", and any other similar terms used herein are to be construed as non-limiting, such that any feature so described need not necessarily be present. Indeed, any combination of optional features is expressly contemplated without departing from the scope of the invention, whether or not expressly claimed. Applicant reserves the right to amend any originally filed claim or to file any new claim accordingly, including the right to amend any originally filed claim to depend upon and / or incorporate any feature of any other claim not originally claimed in that manner. Brief description of the figures

[0038] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0039] [Fig.l] [Fig.l] illustrates a nailer according to an example, which comprises a temperature control means incorporating a thermal actuator for selectively providing a thermal connection between the motor and the fuel cartridge;

[0040] [Fig.2] [Fig.2] illustrates the nailer of [Fig.l] with the temperature control device in the closed position;

[0041] [Fig.3] [Fig.3] illustrates a nailer according to another example, which incorporates a temperature control means incorporating a thermal switch for selectively providing a thermal connection between the motor and the fuel cartridge;

[0042] [Fig.4] [Fig.4] illustrates the nailer of [Fig.3] with the temperature control means in the closed position;

[0043] [Fig.5] [Fig.5] illustrates a nailer according to another example, which includes temperature control means incorporating a valve for selectively providing a flow of air heated by the engine to the fuel cartridge;

[0044] [Fig.6] [Fig.6] illustrates the nailer of [Fig.5] with the valve open; and

[0045] [Fig.7] [Fig.7] illustrates the implementation of a three-way valve. Detailed description of the invention

[0046] Referring now to Figures 1 and 2, a nailer 100 can be seen comprising a motor 101, a fuel cartridge 102 and a temperature control means 103 for selectively providing a thermal connection between a motor 101 and the fuel cartridge 102. In this example, the fuel cartridge 102 is mounted in a portion of the nail magazine of the nail gun 100.

[0047] The engine 101 comprises a piston (not shown) with an elongated and rigid drive blade movably disposed within a cylinder body (not shown), as is known in the art. The fuel cartridge 102 is in the form of a pressurized fuel gas reservoir, which is fluidically connected to the engine to supply it with fuel gas to drive the engine 101 in the usual manner.

[0048] The temperature regulating means 103 comprises a flexible strip 130 formed of a conductive material to establish a thermal bridge between the engine 101 and the fuel cartridge 102. In this example, the flexible strap 130 is fixed at one of its ends to the engine 101, so that its other end is held towards the fuel cartridge 102.

[0049] The temperature control means 103 also comprises a thermal actuator 131, which is mounted on the fuel cartridge 102 and is in thermal contact therewith. The thermal actuator 131 comprises a cylinder 132, which contains a waxy material configured to expand when heated, and a piston 133 which moves within the cylinder 132 in response to the expansion of the waxy material therein. The piston 133 has one end which bears on the flexible strip 130, so that when the temperature of the fuel cartridge 102 increases, the piston 133 moves outward and pushes the flexible strip 130 out of thermal contact with the fuel cartridge 102, thereby breaking the thermal contact between the engine 101 and the fuel cartridge 102.

[0050] [Fig.l] shows the nailer 100 in its pre-operating state, when the temperature of the fuel cartridge 102 is approximately equal to ambient temperature. This is the normal operating temperature of the fuel cartridge 102, and the waxy material of the cylinder 132 is therefore in an expanded state, so that the piston 133 is deployed and the flexible strap 130 is no longer in thermal contact with the fuel cartridge 102.

[0051] In use, the temperature of the fuel cartridge 102 drops as fuel is transferred to the engine, as explained above. In this case, the waxy material inside the cylinder 132 contracts, driving the piston 133 inside the cylinder 132. When the temperature reaches a predetermined minimum limit, the flexible band 130 contacts the fuel cartridge 102, as shown in [Fig. 2].

[0052] When the motor 101 is operating, its temperature increases and when the strap flexible 130 comes into contact with the fuel cartridge 102, a thermal bridge is created between the engine 101 and the fuel cartridge 102. As the temperature of the engine 101 has increased and the temperature of the fuel cartridge 102 has decreased, heat is transferred from the engine 101 to the fuel cartridge 102.

[0053] When the fuel cartridge 102 is heated by the engine 101, the wax contained in the cylinder 132 begins to expand and move the piston 133. When the temperature of the fuel cartridge 102 reaches the predetermined upper limit, the flexible strap 130 is moved away from the fuel cartridge 102, thereby eliminating the thermal bridge. Therefore, the defects associated with a fuel cartridge 102 that is too cold are mitigated.

[0054] Figures 3 and 4 show a nailer 200 according to another example similar to the nailer 100 of Figures 1 and 2, where like references represent like features, incremented by 100. The nailer 200 according to this example differs from that of Figures 1 and 2 in that the fuel cartridge 202 is received in the main body of the nailer 200 and the temperature control means 203 comprises a thermal circuit breaker 231 which selectively closes and opens the power supply from a battery 234 to operate a solenoid actuator 232 which urges the flexible strap 230 to engage and disengage the motor 201.

[0055] The battery 234 is electrically connected to the solenoid actuator 232 via the thermal circuit breaker 231. In this example, the flexible strap 230 is attached at one end to the fuel cartridge 202 and its other end is adjacent to, but biased away from, the engine 201. When the thermal circuit breaker 231 is closed, the battery 234 powers the solenoid actuator 232, which deploys a rod 233 of the solenoid actuator 232 and forces the flexible strap 230 into contact with the engine 201, thereby creating a thermal bridge. When the thermal circuit breaker 231 is open, the rod 233 retracts and the flexible strap 230 moves away from the engine 201.

[0056] The thermal circuit breaker 231 is mounted on the fuel cartridge 202 and is in thermal contact therewith. The thermal circuit breaker 231 is configured to remain open as long as the temperature of the fuel cartridge 202 is above a predetermined minimum limit, as shown in [Fig. 3]. When the temperature of the fuel cartridge 202 falls below the predetermined minimum temperature limit, the thermal circuit breaker 231 closes and forces the flexible strap 230 to engage the motor 201, as shown in [Fig. 4]. When the temperature of the fuel cartridge 202 returns to a predetermined maximum temperature limit, the thermal circuit breaker 231 opens and the solenoid actuator 232 retracts the rod 233, thereby breaking the thermal bridge between the motor 201 and the 202 fuel cartridge.

[0057] Thus, the nailers 100, 200 of Figures 1 to 4 incorporate temperature control means 103, 203 which operate automatically. In the case of the nailer 100 of Figures 1 and 2, the automatic operation is provided by the thermal actuator 131, while the automatic operation is provided in the nailer 200 of Figures 3 and 4 by a thermal circuit breaker 231. However, those skilled in the art will understand that such automatic operation can be achieved using a controller and temperature sensors, for example.

[0058] Figures 5 and 6 show a nailer 300 according to another example similar to the nailer 100 of Figures 1 and 2, where like references represent like features, incremented by 200. The nailer 300 according to this example differs from that of Figures 1 and 2 in that the temperature control means 303 comprises a fan 333 which provides an airflow around the motor 301 and a valve 332 for closing and opening a passage 330 to provide the airflow to the fuel cartridge 302.

[0059] The temperature control means 303 also includes a controller 335 and a temperature sensor 336 associated with the fuel cartridge 302 for measuring the temperature of the fuel cartridge 302. The valve 332 and the temperature sensor 336 are both operatively connected to the controller 335. The controller 335 includes a processor 337 and a memory 338 operatively connected to the processor 337. The memory 338 contains a computer program configured to enable the processor 337 to control the valve 332 based on signals received from the temperature sensor 336, which indicate the temperature of the fuel cartridge 302.

[0060] In use, the fan 333 operates to induce a flow of cooling air around the motor 301 and through a series of openings 310 in the main body of the nailer 300. As long as the temperature of the fuel cartridge 302 measured by the temperature sensor 336 remains above a predetermined temperature limit, the controller 335 maintains the valve 332 in the closed position, as shown in [Fig. 5]. The fuel cartridge 302 is thus isolated from the air flow. When the temperature of the fuel cartridge 302 measured by the temperature sensor 336 falls below the predetermined temperature limit, the processor 337 causes the valve 332 to open and a portion of the air flow previously heated by the motor 301 is directed to the fuel cartridge 302.When the measured temperature returns to a value above the predetermined temperature limit, the processor 337 causes the valve 332 to close.

[0061] The valve 332 illustrated in Figures 5 and 6 opens the passage 330 to allow part of the airflow to be directed to the fuel cartridge 302. However, it may be more advantageous to provide a configuration in which the valve 332 is replaced by a three-way valve 432 which redirects all of the airflow heated by the motor 301, as illustrated in [Fig. 7]. In this case, the openings 310 in the main body of the nailer 300 would be closed to the airflow, thus ensuring that all of the air is directed to the fuel cartridge 302.

[0062] Throughout the specification, the words "comprise" and "contain" and their variations mean "including but not limited to", and are not intended to (and do not exclude) other parts, additives, or whole or partial components. Throughout the specification, the singular includes the plural, unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context otherwise requires.

[0063] Features, integers, characteristics, compounds or groups described in connection with a particular aspect, embodiment or example of the invention should be understood as being applicable to any other aspect, embodiment or example described herein, unless inconsistent therewith.

[0064] List of digital references

[0065] 100 nailer

[0066] 101 engine

[0067] 102 fuel cartridge

[0068] 103 temperature regulation means

[0069] 130 flexible band

[0070] 131 thermal actuator

[0071] 132 cylinder

[0072] 133 piston

[0073] 200 nailer

[0074] 201 engine

[0075] 202 fuel cartridge

[0076] 203 temperature regulation means

[0077] 230 flexible strap

[0078] 231 thermal circuit breaker

[0079] 232 solenoid actuator

[0080] 233 stem

[0081] 234 battery

[0082] 300 nailer

[0083] 301 engine

[0084] 302 fuel cartridge

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] 303 temperature control means 310 openings 330 passage 332 valve 333 fan 335 controller 336 temperature sensor 337 processor 338 memory 432 three-way valve

Claims

Claims

1. A combustion tool (100, 200, 300) comprising a heat source, a fuel cartridge (102, 202, 302) and heat transfer means (103, 203, 303) for selectively transferring heat from the heat source to the fuel cartridge.

2. The combustion tool (100, 200, 300) of claim 1, wherein the heat source comprises an engine (101, 201, 301) configured to receive fuel from the fuel cartridge (102, 202, 302).

3. A combustion tool (100, 200, 300) according to claim 2, wherein the heat transfer means (103, 203, 303) comprises a thermal bridge to provide a conductive path between the motor (101, 201, 301) and the fuel cartridge (102, 202, 302).

4. A combustion tool (100, 200, 300) according to claim 3, wherein the heat transfer means (103, 203, 303) comprises an actuator which moves the thermal bridge between a connected position, in which a conductive path is provided between the motor (101, 201, 301) and the fuel cartridge (102, 202, 302), and a disconnected position, in which the conductive path is interrupted.

5. The combustion tool (100, 200, 300) of claim 4, wherein the actuator comprises a thermal actuator configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge (102, 202, 302) reaches a predetermined maximum threshold and / or to move the thermal bridge to the connected position when the temperature of the fuel cartridge (102, 202, 302) reaches a predetermined minimum threshold.

6. The combustion tool (100, 200, 300) of claim 3, wherein the thermal bridge comprises a bimetallic thermal switch configured to move the thermal bridge to the disconnected position when the temperature of the fuel cartridge (102, 202, 302) reaches a predetermined maximum threshold and / or to move the thermal bridge to the connected position when the temperature of the fuel cartridge (102, 202, 302) reaches a predetermined minimum threshold.

7. A combustion tool (100, 200, 300) according to claim 4, wherein the actuator comprises a motor, an electromagnet or a solenoid.

8. A combustion tool (100, 200, 300) according to claim 7, wherein the heat transfer means (103, 203, 303) comprises a thermal circuit breaker configured to connect the motor (101, 201, 301), the electromagnet or the solenoid to a power source when the temperature of the fuel cartridge reaches a predetermined minimum threshold and / or to disconnect the motor, the electromagnet or the solenoid from the power source when the temperature of the fuel cartridge (102, 202, 302) reaches a predetermined maximum threshold.

9. A combustion tool (100, 200, 300) according to claim 2, wherein the heat transfer means (103, 203, 303) comprises air circulation means for directing a flow of air heated by the engine to the fuel cartridge (102, 202, 302).

10. A combustion tool (100, 200, 300) according to claim 9, wherein the air circulation means comprises a fan for inducing air flow around and / or through the motor (101, 201, 301) and a valve downstream of the motor for selectively allowing air to flow to the fuel cartridge (102, 202, 302).

11. A combustion tool (100, 200, 300) according to any preceding claim, wherein the tool comprises a nailer or stapler.

Images