CN115485102A - Fastener driving device - Google Patents

Abstract

Fastener apparatus including a drive mechanism. Further, the fastener driving apparatus includes a drive mechanism selectively engageable and disengageable with at least one gas spring movable to an energized position upon actuation by the drive mechanism. Further, the apparatus includes an anvil, wherein the drive mechanism includes a first lift mechanism and a second lift mechanism, wherein the first lift mechanism actuates the at least one gas spring during a portion of the operating cycle and then the second lift mechanism actuates the at least one gas spring during a subsequent portion of the operating cycle before the drive mechanism ceases to apply force to the at least one gas spring and the at least one gas spring releases a portion of its potential energy and accelerates the anvil to drive the fastener.

Description

Fastener driving device

Cross Reference to Related Applications

This application claims the benefit of U.S. application No. 17/168,191, filed on day 5, 2/2021, a continuation of U.S. application No. 16/897,304, filed on day 10, 6/2020 (now U.S. patent No. 10,946,504), and the benefit of U.S. provisional application No. 63/020,299, filed on day 5, 2020, each of which is incorporated herein by reference in its entirety.

Background

Electromechanical fastener driving devices (also referred to herein as "drivers", "guns" or "devices") known in the art typically weigh less than 15 pounds and may be configured for fully portable operation. Contractors and homeowners commonly use power-assisted equipment to drive fasteners into wood. These power-assisted devices for driving fasteners may be in the form of, for example, finishing fastener systems for use in skirting or molding in house and home engineering, or in the form of ordinary fastener systems for manufacturing walls or hanging sheaths thereon. These systems may be portable (i.e., not connected or tethered to an air compressor or wall outlet) or non-portable.

The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Disclosure of Invention

In accordance with aspects of the disclosed subject matter, a fastener driving apparatus includes a fastener and at least one gas spring. Further, the fastener driving apparatus includes a drive mechanism selectively engageable and disengageable from the at least one gas spring which is movable to an energized position when engaged by the drive mechanism. Further, the apparatus includes an anvil, wherein the drive mechanism includes a first lift mechanism and a second lift mechanism, wherein the first lift mechanism actuates the at least one gas spring during a portion of an operating cycle and then the second lift mechanism actuates the at least one gas spring during a subsequent portion of the operating cycle before the drive mechanism ceases to apply a force to the at least one gas spring and the at least one gas spring releases a portion of its potential energy and accelerates the anvil to drive a fastener.

The preceding paragraphs are provided as a general introduction and are not intended to limit the scope of the claims below. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

Drawings

A more complete understanding of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 shows a perspective view of a fastener-driving device according to one or more exemplary aspects of the disclosed subject matter;

FIG. 2 illustrates a perspective view of a fastener-driving device with an anvil drive assembly near the point of maximum potential energy in a gas spring in accordance with one or more exemplary aspects of the disclosed subject matter;

FIG. 3 illustrates a perspective view of a gas spring for a fastener driving device according to one or more exemplary aspects of the disclosed subject matter;

FIG. 4 shows a perspective view of a fastener driving device in which a lifter is increasing gas spring compression energy as the gas spring begins to move from the end of a fastener drive stroke, according to one or more exemplary aspects of the disclosed subject matter;

FIG. 5 shows a perspective view of a fastener-driving device according to one or more exemplary aspects of the disclosed subject matter, with the device stopped at an intermediate position;

FIG. 6 shows a perspective view of a fastener-driving device in accordance with one or more exemplary aspects of the disclosed subject matter, wherein there is compliance between the anvil or anvil assembly and the gas spring rod that allows for limited movement in a plane perpendicular to the fastener-driving axis;

FIG. 7 illustrates a perspective view of an anvil assembly comprising at least two different materials of construction according to one or more exemplary aspects of the disclosed subject matter;

FIG. 8 illustrates a perspective view of a fastener-driving device including a minimum radius of curvature in accordance with one or more aspects of the disclosed subject matter; and

fig. 9 illustrates a perspective view of a fastener-driving device including an outboard guide in accordance with one or more aspects of the disclosed subject matter.

Detailed Description

The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the disclosed subject matter and is not necessarily intended to represent the only embodiments. In certain instances, the description includes specific details for the purpose of providing an understanding of the disclosed subject matter. It will be apparent, however, to one skilled in the art that the embodiments may be practiced without these specific details. In some instances, well-known structures and components may be shown in block diagram form in order to avoid obscuring the concepts of the disclosed subject matter.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, characteristic, operation, or function described in connection with the embodiment is included in at least one embodiment of the subject matter disclosed. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, characteristics, operations, or functions may be combined in any suitable manner in one or more embodiments. Further, the embodiments of the disclosed subject matter are intended to and do encompass modifications and variations of the described embodiments.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. That is, as used herein, the terms "a," "an," and the like have the meaning of "one or more" unless expressly specified otherwise. Further, it should be understood that terms such as "left," "right," "top," "bottom," "front," "back," "side," "height," "length," "width," "upper," "lower," "inner," "outer," "interior," "exterior" may be used herein to describe merely a point of reference and do not necessarily limit embodiments of the disclosed subject matter to any particular orientation or configuration. Furthermore, terms such as "first," "second," "third," and the like, merely identify one of the various portions, components, reference points, operations, and/or functions described herein, and as such do not necessarily limit embodiments of the disclosed subject matter to any particular configuration or orientation.

The electromechanical fastener-driving devices currently available have various disadvantages. For example, currently available equipment may have a complex, expensive, and unreliable design. Such as Paslode ^TM The fuel powered mechanism of (a) achieves portability but requires consumable fuel and is expensive. Such as Dewalt ^TM Have a complex coupling or clutch mechanism based on friction devices. Which increases their cost.

Another disadvantage of currently available electromechanical fastener-driving devices includes poor ergonomics. For example, fuel powered mechanisms have a loud combustion sound and combustion fumes. Multiple impact devices are fatiguing and noisy. In addition, non-portability is also an issue. For example, conventional fastener guns are tethered to a stationary compressor and therefore must maintain a separate supply line.

Other disadvantages of currently available electromechanical fastener-driving devices include high reaction forces and short life, safety issues, and return mechanisms. With respect to high reaction forces and short life, mechanical spring drive mechanisms have high tool reaction forces due to their long fastener drive times. Furthermore, the springs are not rated for these types of duty cycles, resulting in premature failure. In addition, consumers are dissatisfied with being unable to install longer fasteners or work with denser wood species. With respect to safety issues, the "air spring" and heavy duty spring driven designs present safety issues, particularly for longer fasteners, because the tendency of the anvil is toward the base plate. This may cause the anvil to strike the operator's hand during the jam clearing process.

With respect to the return mechanisms in currently available electromechanical fastener-driving devices, most of these devices require some drive energy to be available. For example, there is either a bungee cord or spring return that drives the anvil assembly or a vacuum or gas spring is created during movement of the anvil. All of these mechanisms take energy away from the drive stroke and reduce efficiency.

In view of these various disadvantages, there is a need for a fastener-driving device that overcomes these various disadvantages by improving efficiency and safety, for example, as further described herein.

Referring now to the drawings in which like reference numbers represent the same or corresponding parts throughout the several views:

fig. 1 shows a perspective view of a fastener-driving device 100 (also referred to herein as device 100) according to one or more exemplary aspects of the disclosed subject matter. Typically, the device 100 derives power from a power source (preferably a rechargeable battery) and uses a motor to actuate the gas spring. In one aspect, a first (e.g., lower) lifter and a second (e.g., upper) lifter actuate an anvil or anvil assembly that is part of or operably coupled to a gas spring. Actuation of the anvil or anvil assembly on the gas spring increases the potential energy in the gas spring. After such potential energy has sufficiently increased, the anvil or anvil assembly may be released or disconnected from the lifter and the rod of the gas spring may begin to move the anvil or anvil assembly anvil. For example, the movement is toward and into contact with the fastener, causing the anvil to drive the fastener. After such movement of the anvil or anvil assembly, the one or more lifters may reengage the anvil or anvil assembly to return the anvil or anvil assembly to a position where it may act on the gas spring to increase the potential energy contained therein.

By using a multi-stage lifting structure that contacts the anvil or anvil assembly during a substantial portion of the operating cycle, the apparatus 100 allows for more precise control of the operating cycle and improved safety characteristics. For example, the lower lifter may lift the anvil or anvil assembly from the start of the distal-most end of the gas spring to a halfway stabilizing point, at which point the motor may be stopped so that the lower lifter no longer exerts pressure on the anvil/anvil assembly and the upper lifter may continue to pull the anvil/anvil assembly further upward to actuate the gas spring. Thereafter, the upper lifter may be disconnected from the anvil/anvil assembly to allow the gas spring to act on the anvil/anvil assembly and move the anvil/anvil assembly to drive the fasteners. In embodiments, the one or more lifters compress the gas spring to at least 80% of its full travel before stopping the cycle of operation. As a result, when the cycle is restarted (e.g., a user pulls a trigger of the fastener-driving device 100), the gas spring is compressed an additional 20% at most before the gas spring is released from the lifter or lifters and drives a fastener. This is advantageous because the delay (defined as the time between the user actuation of the trigger and the fastener being driven into the substrate) is very short.

The device 100 may also include at least one sensor (e.g., sensor 80) or other device that detects a malfunction (stall) and/or jam in the operation of the device 100. For example, the sensor 80 may be a hall switch, a mechanical switch, an optical switch, or the like. For example, there may be instances when the driving of the fasteners is incomplete (e.g., if the anvil/anvil assembly jams in the downward/driving direction). One or more sensors may operate the motor to remove drive from the anvil and/or anvil assembly prior to signaling a stop to the motor. Further, if it is detected that the current drawn by the motor of the apparatus exceeds the nominal current required to compress the gas spring (e.g., a predetermined multiple of the nominal current), this is an indication that a jam has occurred and, for example, the control circuit may cut off or reduce power to the motor and, optionally, lock one or more lifters and/or anvil/anvil assemblies in place to allow clearing of the jam. For example, the control circuit may decrease the power to the motor in response to the motor current exceeding 150% of the average current draw (e.g., a predetermined multiple of the nominal current) as the potential energy of the gas spring increases. Alternatively or additionally, the control circuit may lock the one or more lifters, or otherwise allow other mechanical elements to lock the one or more lifters, for example, as a one-way clutch. The advantages of this solution include the fact that the mechanism is able to clear itself of slight jamming and protect the device from damage in the case of very severe jamming. Furthermore, it protects the user by relieving the downward pressure on the anvil in case the user has to clear the jam.

The apparatus 100 may also include a one-way bearing that prevents the anvil/anvil assembly from being driven back as it drives the fastener or nail. The apparatus may further include a bumper that may receive at least a portion of the impact force of the anvil/anvil assembly during the operating cycle.

Fig. 2 shows a perspective view of a fastener-driving device in accordance with one or more exemplary aspects of the disclosed subject matter, wherein the anvil drive assembly is proximate a point of maximum potential energy of the gas spring, and fig. 3 shows a perspective view of a gas spring for a fastener-driving device in accordance with one or more exemplary aspects of the disclosed subject matter.

Referring to fig. 1-3, apparatus 100 may include a power source 10, a control circuit 20, a motor 30, a gas spring 40, at least a first riser 44 and a second riser 46, an anvil 62 (which may be part of anvil assembly 60), and at least one buffer 70. The gas spring includes a gas spring rod 42, gas spring rod 42 is at least partially disposed within a sealed chamber (also referred to herein as a gas spring cylinder) 41 as shown in fig. 3, and rod 42 thereof is operably coupled to anvil 62/anvil assembly 60. Bumper 70 is preferably disposed as part of the device to absorb some of the impact force of anvil 62/anvil assembly 60.

First and second lift mechanisms 44 and 46 (each also referred to herein as a "lifter") may include at least one gear 99 configured to engage anvil 62/anvil assembly 60 to selectively move anvil 62/anvil assembly 60 during an operating cycle of apparatus 100. First lifter 44 may move anvil 62/anvil assembly 60 from the first position or position distal of gas spring 40 toward gas spring 40 by rotating itself, gear teeth of the lifter, or other engagement area of the lifter (e.g., roller 43 a) to engage anvil 62/anvil assembly 60. In an embodiment, first lifter 44 moves anvil 62/anvil assembly 60 a portion of the distance toward gas spring 40, and motor 30 may stop or remain running as anvil 62/anvil assembly 60 reaches a midpoint of stability (an example of a midpoint is shown in fig. 5). If the motor 30 is stopped, the motor 30 may be restarted, and then the second lifter 46 continues to lift the anvil 62/anvil assembly 60 toward and against the gas spring 40, thereby moving the rod 42 of the gas spring to increase the potential energy within the gas spring. Second lifter 46 includes an area that does not engage anvil 62/anvil assembly 60 and, when that area is reached, a gas spring may then act on anvil 62/anvil assembly 60 to actuate anvil 62/anvil assembly 60 away from the gas spring to drive fasteners (e.g., via potential energy build up in the gas spring). After the anvil has been released from the lifter and moved toward the fastener, the motor may continue to operate and engage the at least one gas spring to relieve at least 80% of the gas spring force on the anvil.

The apparatus 100 may also include a sensor 80 (e.g., as shown in fig. 2). Sensor 80 may be configured to detect whether the anvil assembly has completed fastener driving and/or a safe stop point in the cycle. Additionally, the sensor 80 may be configured to detect whether an abnormal event has occurred, such as a fastener jam in the apparatus 100 that requires removal of a fastener. For example, the detection may be performed by reading the current consumed by the motor 30. If it is determined that the current drawn exceeds the nominal current for the compressed air spring lever 42, the sensor 80 may signal the control circuit 20 to cut power to the motor 30, thereby preventing damage to the device 100. Additionally, the control circuit may allow the lifter to engage and reduce the load on anvil 62 or anvil assembly 60 from the gas spring. This improves the safety feature by allowing the jam to be cleared safely, as the jam can be cleared without load due to the action of the lifter. In one aspect, the sensor may be configured to detect movement of the anvil or anvil assembly (e.g., movement away from fastener driving), and the at least one lifter may remain energized until the sensor detects such movement of the anvil 62 or anvil assembly 60.

As shown in fig. 3, the gas spring 40 may further include at least one of a seal 48 and a fill valve 49. The seal and/or the filling valve may preferably comprise a single element, such as a lip seal or a cup seal. In an embodiment, the seal is a rod seal disposed on a rod of the gas spring. For example, the gas spring may include a chamber and a rod disposed within the chamber, and a seal (e.g., a rod seal) may act on the rod (e.g., the rod may move linearly within the chamber and relative to the rod seal). The stroke of the rod is preferably at least 80% of the stroke length of anvil 62/anvil assembly 60. These features lead to a number of unexpected operational and geometric improvements. Piston seal made of Senco ^TM And other uses and may lead to various limitations. In one aspect, by using a rod seal, the pressure in the gas spring can be maintained at least 200psi throughout the operational cycle of the device 100. It has been unexpectedly discovered that by using a rod seal and high gas pressure (e.g., in excess of 200 psi), the volume of the gas spring cylinder can be significantly reduced as compared to other electromechanical fastener-driving devices. For example, using a 3/4 "diameter rod seal in a 1.25" diameter gas spring with a gas pressure of 400psia, this configuration is capable of achieving equivalent energy transfer to a 1.5 "diameter gas spring piston with a gas pressure of 100psia and a cylinder diameter of 3.0". In a preferred embodiment, the operating pressure of the apparatus is between 300psia and 500 psia. It was further unexpected to find that increased pressureThe force allows the present apparatus to function more uniformly with respect to ambient pressure. For example, in high altitude cities, such as albertk, new mexico, the nominal atmospheric pressure results in about a 3% reduction in energy in the prior art, but less than 1% in the case of the present device. Another unexpected advantage of the stem seal is that the pressure increase inside the gas spring is much less than that seen in a fastener driver that includes a piston seal rather than a stem seal. That is, the advantage is that the rod seal allows for a more compact size of the device, as the rod seal does not require as much air chamber volume to achieve a constant force for the same stroke. The energy loss in the travel of the gas spring is related to the "displacement air volume" during movement of the gas spring from the energized position to the de-energized position. The amount of air displaced in the case of a rod seal is the area of the rod multiplied by the stroke. In the case of a piston seal, the piston area is multiplied by the stroke, which is a larger area because the piston is necessarily larger than the rod. This results in an unexpected increase in the conversion of gas spring energy to fastener driving energy because less rod seal is lost than piston seals. In summary, the use of a rod seal for a gas spring in a gas spring driven fastener driving device (e.g., device 100) improves efficiency, reduces size, and reduces internal cylinder pressure variations caused by potential energy build-up during activation of the gas spring. This further improves efficiency because a reduction in compression ratio produces less energy loss due to the heat of compression.

In an embodiment, the device 100 does not have a fill valve. During activation, the gas spring fill valve may leak due to the impact characteristics of the fastener driving apparatus. Thus, by not requiring a fill valve, potential leakage due to the fill valve may be reduced.

In an embodiment, referring to fig. 8, the device 100 may include an oil reservoir 91 located between two seals 92, 93 (e.g., O-ring seals, X-ring seals, etc.). For example, when the oil reservoir 91 is located between the two seals 92, 93, the life of the device 100 is significantly improved. More specifically, as the rod travels in a first direction past one seal (e.g., seal 92), it carries away lubricant (e.g., from the reservoir) that is wiped off the other seal (e.g., seal 93). Similarly, when the rod first travels past seal 93 in a second direction (opposite the first direction), the rod carries away lubricant (e.g., from an oil reservoir) that is wiped off seal 92. By positioning the oil reservoir 91 between the two seals 92, 93, the seals are prevented from drying out, which significantly extends the life of the device 100.

In embodiments, two or more lip seals may be used in a gas spring. For example, the two seals 92, 93 may be lip seals. It has been unexpectedly found that this extends the service life of the gas spring. For example, lip seals may accommodate higher pressures and surface speeds than O-rings or X-rings.

In embodiments, it has been unexpectedly found that replacing more conventional steel rods with low density coated rods in a gas spring significantly improves performance. The recoil of the tool when driven is much less as the mass accelerated by the potential energy in the gas spring decreases. In a further refinement, it has been found that satisfactory life can be obtained using a hard coating that is much harder than the rod bushing. For example, the coating may include hard plating, nitride, electroless nickel, and/or ceramic.

In an embodiment, during actuation of the at least one gas spring by the drive mechanism, the pressure increase in the at least one gas spring is less than 30% of the pressure of the gas spring prior to being acted upon by the drive mechanism. The drive mechanism may also include one or more lift mechanisms (first and second lift mechanisms 44 and 46), and references to the drive mechanism and drive and lift mechanisms may be interchanged. In an embodiment, as shown in FIG. 3, the gas spring rod includes a piston flange 90. In a preferred embodiment, the area of the piston flange 90 is no more than 80% of the cross-sectional area of the gas spring cylinder. The relatively small size of the flange 90 relative to the size of the gas spring cylinder helps to significantly increase the energy output of the apparatus 100. In other words, the result is an unexpected increase in the efficiency of the apparatus 100 because the reduced cross-sectional flange configuration improves airflow through the flange. This efficiency is due to the elimination of accidental air braking that can occur during fastener driving strokes due to the high air velocity between the piston flange and the cylinder wall.

FIG. 6 shows a perspective view of a fastener-driving device in accordance with one or more exemplary aspects of the disclosed subject matter, wherein there is compliance between the anvil or anvil assembly and the gas spring rod that allows for limited movement in a plane perpendicular to the fastener-driving axis. In an embodiment, compliance 64 is added between anvil 62 or anvil assembly 60 and gas spring rod 42. Compliance 64 allows for limited movement in a plane generally perpendicular to the fastener driving plane. As a result, it has been unexpectedly found that increasing compliance 64, as shown in fig. 3 and 6, results in an increase in seal and gas spring life as measured by gas spring pressure during the cycle. An exemplary embodiment of such compliance 64 is shown in fig. 3 and 6 in the form of a coupling between the anvil assembly and the gas spring rod. In one aspect, an exemplary coupling of the compliance 64 may be a ball and socket joint arrangement. This unexpected discovery is a result of the loads seen during fastener driving, which previously may have caused the seal 48 to blow out a small amount of gas during impact and/or fastener driving. As a result, the compliance 64 further improves the wear characteristics on the seal by reducing the side loading of the seal from the lifting mechanism. Additionally, referring to FIG. 9, to compensate for offset loads during anvil/anvil assembly lifting, apparatus 100 may include outboard guides 98 to reduce side loads on the gas spring bushings. Outer guide 98 improves the guidance of the anvil assembly and helps prevent misalignment.

Fig. 7 illustrates a perspective view of an anvil assembly including at least two different materials of construction according to one or more exemplary aspects of the present disclosure. In one aspect, referring to fig. 7, it has been found that if the anvil assembly includes a region 66 of the anvil or anvil assembly having a high modulus of elasticity material and high strength (e.g., in the region where the anvil or anvil assembly contacts the lifter) and a region 67 of the anvil or anvil assembly for engagement with the rod, the overall life and operation of the device is improved. Preferably, the portion of the anvil or anvil assembly that contacts the lifter has a modulus of elasticity of at least 2500 ten thousand psi, preferably 2800 ten thousand psi, and a yield strength of at least 100kpsi, and the density of the portion of the anvil assembly that engages the gas spring (including the gas spring rod) is less than 0.15 pounds per cubic inch. Exemplary materials are steel and stainless steel for anvil/anvil assembly components that contact the riser, and aluminum, fiberglass, carbon fiber, or magnesium for air spring rod and air spring rod engagement areas on the anvil/anvil assembly.

In one version, apparatus 100 may also include a one-way bearing or clutch 96 (shown in fig. 2) that prevents anvil 62/anvil assembly 60 from being pulled back during the operating cycle of the apparatus.

Additionally, at least one bumper 70 may be disposed on apparatus 100 for absorbing a portion of the impact force of anvil 62/anvil assembly 60 to reduce wear and tear on the components of apparatus 100. The at least one bumper 70 may be a resilient material and may be disposed at any location on apparatus 100 capable of absorbing a portion of the impact force of anvil 62/anvil assembly 60.

FIG. 4 illustrates a perspective view of a fastener-driving device in which a lifter is increasing the compression energy of a gas spring as the gas spring begins to move from the end of a fastener-driving stroke, according to one or more exemplary aspects of the disclosed subject matter. As shown in fig. 4, at least one lifter can be configured to return anvil 62/anvil assembly 60 and/or hold anvil 62/anvil assembly 60 in position at the distal end of the gas spring prior to beginning another cycle of operation.

In one aspect, the drive cycle of the device 100 disclosed herein may begin with an electrical signal, after which the circuit connects the motor 30 to the power source 10. The motor 30 is operably coupled to at least one lifting mechanism. During an operating cycle of apparatus 100, first or lower lift mechanism 44 may act on anvil 62/anvil assembly 60 to lift anvil 62/anvil assembly 60 from a point distal to gas spring 40. At an intermediate point in the cycle where anvil 62/anvil assembly 60 is stable, motor 30 may stop at a preferred stop point. In one aspect, the stop point corresponds to the drive and lift mechanism having reengaged the gas spring to relieve at least 80% of the force from anvil 62/anvil assembly 60 of the gas spring. It has been found that such stopping achieves a lower delay (i.e., the time between tripping the trigger and driving the fastener) than if the stopping point were not engaging the lifter or engaging only within 10% of the lifting stroke.

As second or upper lift mechanism 46 thereafter continues to actuate anvil 62/anvil assembly 60 into or onto gas spring 40, the mechanism may continue to increase the potential energy within the gas spring. Thereafter, second or upper lift mechanism 46 may eventually be temporarily released or disengaged from anvil 62/anvil assembly 60 to allow gas spring 40 to act against anvil 62/anvil assembly 60 and move anvil 62/anvil assembly 60 toward the point distal of gas spring 40 so that anvil 62/anvil assembly 60 can impact or drive fasteners.

Fig. 5 shows a perspective view of a fastener-driving device, wherein the device stops at an intermediate position, according to one or more exemplary aspects of the disclosed subject matter. By providing a mid-stop point in the operating cycle of the apparatus 100 (e.g., as shown in fig. 5), the following benefits are achieved. The gas spring may be partially energized or loaded prior to the stopping point such that after the at least one riser resumes engagement with the gas spring after the stopping point, a relatively small increase in energy is then required in the gas spring to create a sufficient amount of stored energy in the gas spring for subsequent release to efficiently drive the fastener. In addition, the stop point allows the anvil/anvil assembly to be securely held in a fixed position in the event of a jam in the device so that the operator can clear the jam without fear that the gas spring will apply force to the fastener and pose a danger to the operator.

Fig. 8 illustrates a perspective view of a fastener-driving device (e.g., device 100) including a minimum radius of curvature in accordance with one or more aspects of the disclosed subject matter. In one embodiment, the region 66 may include a radius of curvature 94. In one aspect, the radius of curvature 94 may have a minimum radius of curvature that is at least 25% of the radius of the upper follower. For example, the portion of the region 66 where the release lifter (e.g., the upper lifter in this embodiment) disengages from the lift plate may have a minimum radius of curvature. Initially, it was believed that a small radius of curvature would result in a tool with better performance, but it was unexpectedly found that a small radius of curvature would generate very large forces when the upper follower is released from the anvil assembly, resulting in severe deformation, wear and shorter tool life. Thus, in embodiments, the radius of curvature may be at least 25%, preferably 50%, of the radius of upper follower 95. Additionally, in embodiments, the device 100 may include an over-run capability to reduce side loads on the gas spring bushings from the riser at the release point.

Fig. 9 illustrates a perspective view of a fastener-driving device (e.g., device 100) including an outboard guide 98 in accordance with one or more aspects of the disclosed subject matter. As shown in fig. 9, apparatus 100 may include a gas spring cylinder 41, a motor 30, an anvil assembly 60, a rod 42, and a bushing having a seal 97. As described herein, the outer guide 98 can reduce side loads on the gas spring rod.

Having now described embodiments of the disclosed subject matter, it should be apparent to those skilled in the art that the foregoing is merely illustrative and not limiting, having been presented by way of example only. Thus, while particular configurations have been discussed herein, other configurations may also be employed. Many modifications and other embodiments (e.g., combinations, rearrangements, etc.) can be made by the present disclosure and are within the scope of one of ordinary skill in the art, and are intended to be within the scope of the disclosed subject matter and any equivalents. Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Moreover, some features may sometimes be used to advantage without a corresponding use of the other features. Accordingly, applicants intend to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of the disclosed subject matter.

Claims (20)

1. A fastener driving device comprising:

an anvil assembly including an anvil engaged with the fastener,

at least one gas spring defining a chamber and having a stem disposed within the chamber, the gas spring including a stem seal that is stationary relative to movement of the stem;

a power driven actuator configured to selectively drive the at least one gas spring, the at least one gas spring configured to move to an energized position after engagement by the actuator, the actuator continuing to operate and reengaging the gas spring to relieve pressurization pressure on the anvil before the actuator ceases to apply force to the at least one gas spring and the at least one gas spring releasing at least a portion of the potential energy to accelerate the anvil to drive the fastener, the actuator operating to actuate the at least one gas spring for a portion of an operating cycle.

2. The fastener driving device according to claim 1, wherein the actuator includes at least one lifter and at least one lifting plate.

3. The fastener driving device according to claim 1, wherein at least two lifters are used to energize the gas spring.

4. The fastener driving device according to claim 1, wherein the gas spring has an operating pressure of at least 200psia throughout an operating cycle.

5. The fastener driving device according to claim 1, further comprising at least one sensor.

6. The fastener driving device according to claim 5, wherein the at least one sensor is configured to detect movement of the anvil away from the fastener.

7. The fastener driving apparatus according to claim 6, further comprising at least one lifter, wherein the at least one lifter remains powered until the sensor detects movement of the anvil away from the fastener.

8. The fastener driving device according to claim 1, wherein the stem is guided by at least two contact surfaces, wherein the at least two contact surfaces are separated by a distance equal to at least 150% of the diameter of the stem during the portion of the cycle for adding potential energy to the gas spring.

9. The fastener driving device according to claim 1, wherein the control circuit is configured to

While the potential energy of the gas spring is increasing, reducing power to the motor in response to motor current exceeding 150% of average current draw.

10. The fastener driving device according to claim 1, the actuator further comprising a one-way clutch.

11. A fastener driving device comprising:

at least one gas spring defining a chamber and having a stem disposed within the chamber, the gas spring including a stem seal that is stationary relative to movement of the stem;

a seal acting on the stem, the stem configured to move linearly within the chamber relative to the seal;

wherein the rod further comprises a flange, wherein the rod flange area is no more than 80% of the cross-sectional area of the gas spring cylinder;

an anvil assembly comprising an anvil,

wherein the actuator is configured to actuate the at least one gas spring for a portion of the operating cycle before the actuator ceases to apply force to the at least one gas spring and the at least one gas spring releases at least a portion of the potential energy and accelerates the anvil to drive the fastener.

12. The fastener driving device according to claim 11, wherein the operating cycle of the actuator includes a stop point in which the actuator reengages the gas spring to relieve at least 80% of the force on the anvil from the gas spring.

13. The fastener driving device according to claim 11, wherein the pressure in the gas spring is at least 200psi throughout the cycle.

14. The fastener driving device according to claim 11, wherein the control circuit is configured to

While the potential energy of the gas spring is increasing, reducing power to the motor in response to motor current exceeding 150% of average current draw.

15. The fastener driving apparatus according to claim 11, wherein the actuator includes at least one lifter and at least one lifting plate.

16. The fastener driving device according to claim 11, wherein the rod is guided by at least two contact surfaces, wherein the at least two contact surfaces are separated by a distance equal to at least 150% of the diameter of the rod during the portion of the cycle in which the potential energy is added to the gas spring.

17. The fastener driving device according to claim 11, further comprising at least one sensor.

18. The fastener driving apparatus according to claim 17, wherein the at least one sensor is configured to detect movement of the anvil away from the fastener.

19. The fastener driving apparatus according to claim 18, further comprising at least one lifter, wherein the at least one lifter remains powered until the sensor detects movement of the anvil away from the fastener.

20. The fastener driving device according to claim 11, wherein the actuator further comprises a one-way clutch.

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