FASTENER DRIVING APPARATUS

Abstract

A fastener driving apparatus comprises an energy storage means, a drive mechanism, and an anvil assembly. The drive mechanism selectively engages the energy storage means to store potential energy within the energy storage means. After the drive mechanism disengages, potential energy previously stored within the energy storage means impart a force on the anvil assembly to launch the assembly (and incorporated anvil) to drive a fastener. The drive mechanism may comprise a cam for engaging and disengaging the energy storage means. The apparatus may also comprise a nail indexing mechanism for supplying fasteners, which indexing mechanism may also be acted and operated on by the cam. The apparatus may further comprise a gas spring as a return mechanism for returning the anvil assembly to a position after the anvil assembly has separated from the energy storage means.

Claims

1. A fastener driving apparatus, the apparatus comprising a power source, a control circuit, a motor, a drive mechanism, an anvil assembly, said anvil assembly comprising an anvil, at least one gas spring, said at least one gas spring comprising a chamber and a piston disposed within said chamber, said gas spring operationally coupled to said anvil assembly, wherein said drive mechanism causes said anvil assembly to move from a first position to a second position to drive a fastener, and wherein said gas spring thereafter returns said anvil assembly to said first position.

2. The fastener driving apparatus of claim 1, said apparatus further comprising a second gas spring, wherein said anvil assembly is moved from said first position to said second position to drive a fastener by said second spring.

3. The fastener driving apparatus of claim 2, wherein said second spring comprises two or more springs.

4. The fastener driving apparatus of claim 1, said fastener driving apparatus further comprising an energy storage means, wherein said anvil assembly is moved from a first position to a second position to drive a fastener by said energy storage means and wherein said gas spring thereafter moves said anvil assembly back to a first position.

5. The fastener driving apparatus of claim 4, wherein said piston of said piston weighs less than 20 grams.

6. The fastener driving apparatus of claim 5, wherein said piston comprises one of aluminum, magnesium and titanium.

7. A fastener driving apparatus, the apparatus comprising a power source, a control circuit, a motor, an energy storage means, a drive mechanism, said drive mechanism capable of selectively engaging and disengaging said energy storage means, and said energy storage means capable of moving to an energized position, upon being engaged by said drive mechanism a nail indexing mechanism, and an anvil assembly, said anvil assembly comprising an anvil, wherein said drive mechanism comprises an engagement region for engaging and causing said energy storage means to increase in potential energy and a non-engagement region wherein said drive mechanism ceases to increase the potential energy of said energy storage means, wherein said drive mechanism comprises an engagement region for engaging said nail indexing mechanism to move said nail indexing mechanism to index a nail, and a non-engagement region for causing said nail indexing mechanism to cease moving. wherein after potential energy is increased in said energy storage means and after said drive mechanism thereafter disengages said energy storage means, said energy storage means accelerates said anvil to drive a fastener.

8. The fastener driving apparatus of claim 7, wherein said nail indexing mechanism comprises at least one of a cam follower, a linkage and a spring.

9. The fastener driving apparatus of claim 7, wherein said energy storage means is one of a mechanical spring, gas spring, vacuum and compressed air.

10. A fastener driving apparatus, the apparatus comprising a power source, a control circuit, a motor, an energy storage means, a drive mechanism capable of selectively engaging and disengaging said energy storage means, said energy storage means capable of moving to an energized position upon being engaged by said drive mechanism, an anvil assembly, said anvil assembly comprising at least an anvil, wherein said drive mechanism comprises an engagement region for engaging and causing said energy storage means to increase in potential energy and a non-engagement region wherein said drive mechanism ceases to increase the potential energy, wherein after said drive mechanism disengages said energy storage means, said energy storage means accelerates said anvil assembly to drive a fastener and wherein said anvil assembly separates from said energy storage means for at least a portion of the fastener drive stroke.

11. The fastener drive apparatus of claim 10 wherein said drive mechanism has a clutch, said clutch capable of retaining said drive mechanism in an intermediate stoppage point before said drive mechanism disengages said energy storage means.

12. The fastener drive apparatus of claim 10, said apparatus further comprising a gas spring, wherein said anvil assembly is biased towards a first position by said gas spring.

13. The fastener driving apparatus of claim 10 wherein said drive mechanism includes a cam and spring arrangement for indexing a fastener.

14. The fastener driving apparatus of claim 10, wherein the energy storage means comprises a gas spring, said gas spring comprising a piston, and wherein the mass of said piston of the gas spring is less than 50% of the mass of the anvil assembly.

15. The fastener driving apparatus of claim 10, wherein the energy storage means includes one of a gas spring, mechanical spring or elastomeric spring.

16. The fastener driving apparatus of claim 10, wherein said drive mechanism comprises one of a cam and a rack and pinion.

Description

DESCRIPTION OF THE DRAWINGS

[0045] The advantages and features of the present disclosure will become better understood with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, in which

[0046] FIG. 1 is a cutaway view of a fastener driving apparatus in a first operating position, in accordance with an exemplary embodiment of the present disclosure;

[0047] FIG. 2 is a cutaway view of a fastener driving apparatus in a second operating position with the anvil assembly separated from the energy storage means, in accordance with an exemplary embodiment of the present disclosure;

[0048] FIG. 3 is a view showing a gas spring as a return mechanism of a fastener driving apparatus for returning an anvil assembly) from a second position to a first position in accordance with an exemplary embodiment of the present disclosure; and

[0049] FIG. 4 is a view showing an indexing mechanism of a fastener driving apparatus for sequencing a nail, in accordance with an exemplary embodiment of the present disclosure.

[0050] Like reference numerals refer to like parts throughout the description of several views of the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0051] A best mode for carrying out the present disclosure is presented in terms of its preferred embodiment, herein depicted in the accompanying figures. The preferred embodiments described herein detail for illustrative purposes are subject to many variations. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but are intended to cover the application or implementation without departing from the spirit or scope of the present disclosure. Furthermore, although the following relates substantially to one embodiment of the design, it will be understood by those familiar with the art that changes to materials, part descriptions and geometries can be made without departing from the spirit of the disclosure. It is further understood that references such as front, back or top dead center, bottom dead center do not refer to exact positions but approximate positions as understood in the context of the geometry in the attached figures.

[0052] The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.

[0053] Referring also to the figures, the present disclosure provides for a fastener driving apparatus 100. In an embodiment, the apparatus 100 comprises a power source 10, a control circuit 20, a motor 30, an energy storage means (such as, in an embodiment, at least one spring 40), a drive mechanism 50, an anvil assembly 60 (which anvil assembly comprises an anvil 62) and a one-way clutch 54. The apparatus 100 may further comprise an anvil return mechanism 64 and at least one bumper 70. The at least one spring 40 is preferably a gas spring and includes a piston (or pushing element) 42, which piston 42 is at least partially disposed within a sealed chamber 44, and which piston 42 is selectively actuated by the drive mechanism 50. A bumper 72 is preferably disposed within the at least one gas spring 40 to absorb a portion of the force of impact of the piston 42. The at least one gas spring 40 further comprises a nose portion 46 (which nose portion may be a part of or coupled to the piston) and which nose portion 46 extends out of the chamber and which makes operative contact with the anvil assembly 60 during a portion of the operational cycle of the apparatus 100.

[0054] The drive mechanism 50 preferably comprises a cam-driven mechanism 52 as illustrated in FIGS. 1 and 2 although it is contemplated that any such arrangement which allows selective engagement and disengagement (such as an interrupted rack and pinion) may be used. It will be apparent that the drive mechanism 50 is configured to permit transition from engagement with the potential energy storage means (such as gas spring 40) to disengagement from the potential energy storage means (such as gas spring 40). The drive mechanism 50 is operatively coupled to the gas spring 40, and in a particular embodiment, to the piston 42 such that the drive mechanism 50 may alternate in actuating the piston 42 (when the cam is engaged, for example, and as shown in FIG. 1) and in refraining from applying a drive force on the piston (as shown in FIG. 2). A one-way clutch 54 is configured within the drive mechanism to allow the drive mechanism 50 to stop and retain the gas springs in an energized position prior to releasing the anvil assembly 60. It will be apparent that other devices for stopping and retaining the drive mechanism at an intermediate energized position may be provided—including, but not limited to, a wrap spring or ratchet and pall arrangement.

[0055] In an embodiment, the drive mechanism 50 engages and actuates the piston(s) 42 (and/or anvil assembly 60) to store potential energy within the gas spring(s) 40, which actuation of the piston(s) 42 may be referred to as an “energized position” of the piston(s) 42. In an embodiment, the initial pressure (before the drive mechanism 50 actuates the piston(s) 42) within the gas spring(s) 40 is at least 40 psia. The configuration and design of the gas spring 40 are such that the pressure increase during the piston movement is less than 40% of the initial pressure, and in an embodiment, less than 25% of the initial pressure, which allows the drive mechanism 50 to operate at a more constant torque, thus improving the motor efficiency. The drive mechanism 50 thereafter disengages the piston(s) 42 (and/or anvil assembly 60), allowing potential energy to act on the piston(s) 42 and cause the piston(s) 42 to move and act on the anvil assembly 60 (as will be described in further detail below). The drive mechanism 50 is timed and/or configured to prevent further engagement with the gas spring(s) 40 until after the anvil assembly 60 has returned to an approximate starting position. The drive mechanism 50 may thereafter again act on the piston(s) 42 to again store potential energy within the gas spring(s) 40 and may thereafter again temporarily cease to act on the piston(s) 42 (and/or anvil assembly 60) to allow potential energy to instead act on the pistons 42. In an embodiment, the stroke of the piston(s) 42 is less than stroke of the anvil assembly 60.

[0056] The anvil assembly 60 is operatively coupled to the gas spring(s) 40, such as to the piston(s) 42 or nose portion such that when the piston(s) 42 is released under pressure from the drive mechanism 50, the force from the piston(s) 42 is imparted onto the anvil assembly 60, causing the anvil assembly 60 to move in a direction and to release (or be launched) away from the piston(s) 42 and drive a fastener, for example. As shown in FIG. 2, the anvil assembly may separate from the energy storage means for a portion of the fastener drive stroke of the anvil assembly. It was discovered in the course of developing the disclosure that for the launched case that the ratio of the thrown mass to the moving mass within the gas spring(s) 40 (primarily the piston(s) 42) was exceedingly important to the efficiency of the fastener driving apparatus 100. It is preferred to have thrown mass (which in this case is the anvil assembly 60) that is greater than 50% of the total moving mass (anvil assembly mass+gas springs moving mass) and even more preferable to have the anvil assembly mass at least 60% of the total moving mass. This discovery allows the present disclosure to have increased efficiency in transferring the potential energy into driving energy on the fastener. In an embodiment, the mass of the anvil assembly 60 is at least two times the mass of the piston(s) 42. In an embodiment, the piston(s) 42 has a mass of about 30 grams and the anvil assembly 60 has a mass of about 160 grams. In an embodiment, the piston(s) 42 are hollowed out to reduce mass and further may be constructed of lightweight materials such as hard anodized aluminum, plastics or the like. The anvil assembly 60 may be operatively coupled to a guide, shaft, or other structure that limits and guides the range of motion of the anvil assembly 60.

[0057] A sensor 90 is provided for determining at least one position of the apparatus to enable the proper timing for stopping the operational cycle of the apparatus. Further, this information can be used to detect a jam condition for proper recovery.

[0058] At least one bumper 70 may be disposed on the apparatus 100 for absorbing a portion of the force of impact of the piston(s) 42 within the gas spring(s) 40 or of the anvil assembly 60, to reduce wear and tear on the components of the apparatus 100. The at least one bumper 70 may be of an elastic material, and may be disposed on the apparatus 100 at any position where it is capable of absorbing a portion of the force of impact by the piston(s) 42 or the anvil assembly 60.

[0059] The anvil assembly 60 further comprises a return mechanism 64 to enable the anvil assembly 60 to return to a position where it can be again contacted or acted on by the gas springs 40. In an embodiment, the return mechanism 64 is a return energy storage means that is disposed on or in the guide or shaft that constrains the anvil assembly 60. The return mechanism 64 may comprise, in an embodiment, a mechanical spring, a gas spring or an elastomeric spring), which return mechanism would be disposed nearer the end or portion of the anvil assembly 60 that is distal to the gas spring(s) 40. In a preferred embodiment, the return mechanism may be a gas spring (as shown in FIG. 3.) After the gas springs 40 cause the anvil assembly 60 to move, and after or in connection with the anvil 62 impacting and driving a fastener, the return mechanism 64 imparts a force on the anvil assembly 60 to cause the anvil assembly 60 to return to a position where it may again be operatively acted upon by the gas springs 40. In the embodiment where the return mechanism 64 is a gas spring, the gas spring return mechanism may push or otherwise act on a tab or other element disposed on the anvil and/or anvil assembly to cause the anvil and/or anvil assembly to return to a position where it can again be operatively acted on by gas spring(s) 40.

[0060] The apparatus may further comprise a nail indexing mechanism 80, as shown in FIG. 4. In an embodiment, the drive mechanism includes a cam 82 for indexing a nail in the apparatus. The cam motion and timing are used to feed nails, such as in a coil nailing system. In an embodiment, the cam motion is used to drive linkages 83 of the nail indexing mechanism to index a nail. In another embodiment, motion of the cam 82 may compress a spring 84 of the nail indexing mechanism, which spring 84 may then index a nail. In an embodiment, the cam of the drive mechanism may engage the anvil to energize the gas springs in one direction while simultaneously engaging a linkage to drive the nail indexing mechanism in the opposite direction. It will be apparent that these motions are out of phase such that the nail is indexed before the gas spring is released to drive the fastener.

[0061] In an embodiment, the cam 82 starts its rotation after start of the operational cycle and engages a linkage 83 of nail indexing mechanism 80. This motion moves the linkage 83 downward and retracts a feeding mechanism 86 of the nail indexing mechanism 80, compressing a spring of the feeding mechanism 86. As the cam 82 continues its rotation, full stroke of the linkage 83 of the nail indexing mechanism is achieved, and the cam releases the linkage. The linkage 83 of the nail indexing mechanism 80 may be biased by a spring that returns it to its start position. As the linkage 83 retracts, the feeding mechanism spring of the nail indexing mechanism 80 releases the feeding mechanism 86 and indexes the nail into position beneath the anvil assembly 60 and/or anvil 62.

[0062] The present disclosure offers the following advantages: the gas springs, mechanical springs and elastomers are capable of generating a relatively high amount of force in a small amount of space such that the size of the apparatus may be smaller than other fastener drivers. Further, because of the relatively small increase from the initial pressure in the gas spring during an energy storage cycle and the shapes of the cam, the motor can operate at a relatively constant torque during energy storage thus leading to a longer useful life of the apparatus. Furthermore, it was unexpectedly discovered that this disclosure has an improved safety profile. For example, if a nail becomes jammed, the potential energy of the gas spring(s) does not act directly on the fastener and thus while the user removes the fastener, there is reduced potential for injury. It was a further unexpected discovery of the present disclosure that the apparatus has an improved recoil force as opposed to conventional and or prior fastener disclosures. This was a totally unexpected discovery as the anvil/anvil assembly is a free traveling mass and as such during the course of the driving of the fastener does not put a reactionary force on the operator. In contrast and in prior art tools, air pressure or other force on the piston and anvil assembly often acts during the entire drive and can result in significant recoil to the operator.

[0063] The foregoing descriptions of specific embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiment was chosen and described in order to best explain the principles of the present disclosure and its practical application, to thereby enable others skilled in the art to best utilize the disclosure and various embodiments with various modifications as are suited to the particular use contemplated.