EP4732999A1

EP4732999A1 - A device and a method for driving a fastener into a workpiece

Info

Publication number: EP4732999A1
Application number: EP24208520.7A
Authority: EP
Inventors: Rolf Erhardt; Joerg Stamm; Bernhard Andreas Hormann
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2024-10-24
Filing date: 2024-10-24
Publication date: 2026-04-29
Also published as: WO2026087249A1

Abstract

A device (110) for driving a fastener into a workpiece, preferably wherein the fastener is a nail, comprising:
- an air spring chamber (112), preferably wherein the air spring chamber (112) is an air spring cylinder;
- a piston (114), wherein the piston (114) is arranged within the air spring chamber (112) in a manner that the piston (114) is moveable from a ready position along a drive axis (140) in order to force the fastener into the workpiece;
- a preload system (116), wherein the preload system (116) is configured for preloading the device (110) by forcing the piston (114) in the ready position applying a preloading force;
wherein the preload system (116) comprises
o a chain (142) configured to transmit the preloading force to the piston (114) or
o a hydraulic system (150) configured to transmit the preloading force to the piston (114).

Description

Technical Field

The present invention relates to a device and a method for driving a fastener into a workpiece.

Background art

JP2018051715A relates to a driving machine that can change driving energy of a driving piece. The driving machine includes: a cylinder chamber for storing a gas; a driving piece moving in a first direction with pressure from the cylinder chamber to drive a fastener; a pressure accumulating chamber for storing a gas to be fed to the cylinder chamber; a flow passage through which the gas passes when being fed to the cylinder chamber from the pressure accumulating chamber; and an adjustment mechanism capable of changing flow resistance of the gas in the flow passage.
US 2020/282534 A1 relates to an electric nail gun including a muzzle seat, a safety component being movable relative to the muzzle seat, and a cylinder unit connected to the muzzle seat and including a striking cylinder, at least one storage chamber that is adapted for storing pressurized air, and a sealing cap that is coupled to the striking cylinder and the at least one storage chamber. The electric nail gun further includes an air valve disposed in the cylinder unit and being co-movable with the safety component from a closed position to an open position to allow the pressurized air to flow into the striking cylinder, and a nail-striking unit driven movably by the pressurized air for striking a nail when the air valve is at the open position.
US 2023/088831 A1 relates to a power tool including an air spring cylinder. A piston is movably positioned within the cylinder and a driver blade and a rack are attached to the piston. The power tool includes a lifter gear including a lifter gear wheel portion, and a plurality of teeth extending radially from the lifter gear wheel portion and configured to engage the rack. A hub includes a first end operably connected to a motor output and a second end including a hub wheel portion. A first receptacle is provided in one of the lifter gear and the hub and a first bearing element extends from the other of the lifter gear and the hub into the first receptacle. A first elastomeric damper is positioned within the first receptacle between the first bearing element and a bearing element defined portion of the first receptacle.

Problem to be solved

It may be therefore desirable, preferably in view of US 2023/088831 A1 , to provide a device and a method for driving a fastener into a workpiece that at least partially overcome the problems of the state of the art.
In particular, it may be an object of the present invention to prevent wear of the components of the device. Further in particular, it may be an object of the present invention to provide a particular robust preloading system of the device, preferably since the piston may be more simple and/or since the inertial force may now act exclusively in the driving axis. Further in particular, it may be an object of the present invention to provide a particular compact design of the device, preferably since an electrically driven driving unit may be arranged at more flexible positions.

Summary

This problem is addressed by a device and a method for driving a fastener into a workpiece with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.
In a first aspect, a device for driving a fastener into a workpiece is disclosed. The fastener may be a nail. The device comprises:

an air spring chamber, preferably wherein the air spring chamber is an air spring cylinder;
a piston, wherein the piston is arranged within the air spring chamber in a manner that the piston is moveable from a ready position along a drive axis in order to force the fastener into the workpiece;
a preload system, wherein the preload system is configured for preloading the device by forcing the piston in the ready position applying a preloading force;

∘ a chain configured to transmit the preloading force to the piston or
∘ a hydraulic system configured to transmit the preloading force to the piston.

The term "air spring chamber" may refer to chamber configured for supporting the piston. The piston may be moveable within the air spring chamber. The air spring chamber may be configured to guide the movement of the piston. The movement of the piston may be a translational movement. The movement may be along a drive axis. The movement may be in a preload direction and/or in a fastening direction. The fastening direction may be opposite to the preload direction.
The device may further comprise:

a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber,

The device may further comprise:

an air flow regulating element, preferably wherein the air flow regulating element is a valve, wherein the air flow regulating element is configured to seal, in a closed position of the air flow regulating element, a first chamber compartment of the pressurized volume from a second chamber compartment of the pressurized volume.

The air flow regulating element may be further configured to enable, in an open position of the air flow regulating element, an air flow from the first chamber compartment into the second chamber compartment in order to drive the movement of the piston such that the fastener is forced into the workpiece, preferably wherein said movement of the piston causes the pressurized volume to increase.
The term "pressurized volume" may refer to volume formed by at least the pressure chamber. The pressurized volume may be further formed by the air spring chamber and/or the piston.
A pressure within the pressurized volume that is minimized may be, typically, larger than 4 bar.
When the air flow regulating element is in a closed position, it may separate the pressurized volume into a first chamber compartment and a second chamber compartment such that the first chamber compartment is sealed from the second chamber compartment in a manner that no air flow between the first chamber compartment and the second chamber compartment is possible. When the air flow regulating element is in the closed position, the air within the pressurized air within the second chamber compartment may apply a force onto the piston. The air within the second chamber compartment may be in contact with the piston. On the other hand, the pressurized air within the first chamber compartment may apply no force onto the piston. The air within the first chamber compartment may not be in contact with the piston. Typically, the first chamber compartment may be larger than the second chamber compartment by a factor of 5, preferable when the piston is in the ready position.
The device may further comprise:

a plunger; wherein the plunger is configured for bringing the air flow regulating element from the closed position of the air flow regulating element in the open position of the air flow regulating element.

The term "plunger" may refer to a solid rod and/or a solid cylinder. The plunger may be supported by the pass-through. The plunger may be movably arranged within the pass-through. Thereby, the plunger may be translationally moveable. The movement of the plunger may bring the air flow regulating element from the closed position in the open position. For bringing the air flow regulating element from the closed position of the air flow regulating element in an open position of the air flow regulating element, the plunger may be moveable along a plunger axis.
The device may further comprise:

a workpiece contact unit, wherein the workpiece contact unit is configured to move the plunger for bringing the air flow regulating element from the closed position of the air flow regulating element in the open position of the air flow regulating element when the workpiece contact unit contacts the workpiece.

The device may further comprise a workpiece contact unit, wherein the workpiece contact unit is attached to the plunger. The workpiece contact unit may be configured to move the plunger for bringing the air flow regulating element from the closed position of the air flow regulating element in the open position of the air flow regulating element when the workpiece contact unit is pressed against the workpiece. When the workpiece contact unit is pressed against the workpiece, the workpiece contact unit may move, specifically translationally move. Said movement may cause the movement of the plunger required to bring the air flow regulating element in the open position.
Further, the workpiece contact unit can be an integral part of the nose of the device or can be a separated part of the nose of the device. In other words: For bringing the air flow regulating element from the closed position in the open position the nose of the device can be pressed against the workpiece and/or the workpiece contact unit can be pressed against the workpiece.
As already indicated, the device comprises a "preload system", wherein the preload system is configured for preloading the device by forcing the piston in the ready position. Thereby the preload system may actively decrease the pressurized volume.
The term "chain" may refer to series of connected links, typically made of metal, designed to transmit motion or force, or to secure objects. The chain may be or may comprise stiffening element configured to stiffen the chain when the chain is unguided. The chain may further be guided by at least one guiding element comprised by the device in order to change a translational direction of the chain in a manner that the chain is bent.
The term "hydraulic system" may refer to a mechanical system using pressurized fluid to transmit the preloading force. The hydraulic system may be or may comprise a hydraulic fluid container, preferably being a high pressure reservoir, and/or an hydraulic cylinder surrounding a lifting member comprised by the piston, and/or a 4-way-valve. The fluid may be a pneumatic fluid, specifically a pneumatic incompressible fluid .
When the preload system comprises a chain, the device may further comprise

an electrically driven driving unit, wherein the electrically driven driving unit is configured to move the chain in order to move the piston along the drive axis. When the preload system comprises a hydraulic system, the device may further comprise
a hydraulic pump, wherein the hydraulic pump is configured to generate a pressure in order to move the piston along the drive axis.

The preload system may be configured to move the piston along the drive axis in a preload direction and in a fastening direction. The preload direction may be the direction in which the device is brought in the ready position. The fastening direction may be the direction in which the piston is forced in order to force the fastener into the workpiece.
The preload system may comprise a lifting member, wherein the preload system transmits the preloading force to the piston via the lifting member. The preload system may further be configured to maintain the piston in the ready position, specifically against the pressure caused by the air in the pressurized volume.
The device may further comprise:

a retaining member, wherein the retaining member is configured to maintain the piston in the ready position.

The term "retaining member" may refer to a mechanical component used to hold and/or secure a further component in place in order to prevent movement and displacement of the further component. The retaining member may be a pivot that engages in a notch or protrusion of the driver of the piston and/or the piston. The protrusion of the driver may be formed be a separate element. The retaining member may be a circular element situated annularly around the driver. The retaining member may be released when the device detects a triggering action by the user at a time when the air flow regulating element is in the open position. Alternatively, the retaining member may solely function as a backup or safety component and the piston is retained by friction when the air flow regulating element is in the closed position until the air flow regulating element brought in the open position by a triggering action of the user. Thereby the air flow regulating element may be or may be used as a retaining member.
The device may further comprise:

a driver that is fixedly attached to the piston, wherein the driver is forced against the fastener in a manner that the fastener is forced into a workpiece when the preloading of the device is released.

In order to the drive the movement of the piston such that the driver that is attached to the piston is forced against the fastener in a manner that the fastener is forced into a workpiece, the air within the pressurized volume may be caused to expand abruptly.
Therefore, the air flow regulating element may be brought in the open position, such that an air flow between the first chamber compartment and the second chamber compartment is possible. Thereby, the first chamber compartment may no longer form a closed volume. Rather, the air within the first chamber compartment may drive the movement of the piston by flowing through the air flow regulating element into the second chamber compartment. When the air flow regulating element is in the open position, the preloading of the device may be released. This causes the air within the pressurized volume to expand abruptly and, thereby, move the piston. The preloading may be release by a user that presses a trigger comprised by the device. This may be called a triggering action.
In order to release the preloading of the device, the preload system that maintains the piston in the ready position may release the force that is thereto applied onto the piston. Alternatively or in addition, the retaining member may release the force that is thereto applied onto the piston in order to release the preloading of the device.
The movement of the piston may cause the driver to move in the fastening direction. Thereby, a further volume may decrease, which may, typically, allow gaseous exchange with the environment, typically air. The gaseous exchange may be allowed via at least one ventilation hole within the air spring chamber.
As a result of said movement, the driver may contact the fastener at a contact surface of the driver and, thereby, drive the fastener into the workpiece. The driver may be an integral part of the piston. A cross-section of the piston in a plane orthogonal to the drive axis may be of an arbitrary shape. Preferably, the cross-section of the piston in the plane orthogonal to the drive axis may be of a circular shape.
The preload system at least partially may run through a further volume at least partially enclosed by the air spring chamber. This may advantageously allow a compact design of the device, since a part of the preload system can be situated in the further volume that is free of further components.
The chain may be bent. Preferably, a portion of the chain that is outside of the air spring chamber may be bent. This may further contribute to the compact design, since the arrangement of the further components of the device, specifically the electrically driven driving unit, may be more flexible.
It may be approached that the hydraulic system may further comprise at least one pipe that is bent. Preferably, a portion of the pipe that is outside of the air spring chamber may be bent. This may further contribute to the compact design, since the arrangement of the further components of the device, specifically the electrically driven driving unit, may be more flexible.
The preload system may be fixedly attached to the piston. This may increase the stability of the device. Alternatively, the preload system may be configured to decouple from the piston when the piston is in the ready position in a manner that the piston is moveable along the drive axis in order to force the fastener into the workpiece independent from the preload system.
The term "decoupling" may refer to the process of reversibly mechanically separating at least two components so that they are no longer attached to each other in a manner that flow of force between the components is possible. The device may further be configured to remove the preload system out of the flight path of the piston when piston is in the ready position. Consequently, when the preloading force is released in order to force the fastener into the workpiece, the preload system does not impact the flight of the piston, such as by colliding with the piston. This advantageously minimizes interference of both components and improves control and performance of the device.
In a further aspect, a method for forcing a fastener into a workpiece is disclosed, wherein the method comprises using a device according to any one of the preceding claims, wherein the device is used to force a fastener into a workpiece.
As used in the following, the terms "have", "comprise" or "include" or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions "A has B", "A comprises B" and "A includes B" may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.
Further, it shall be noted that the terms "at least one", "one or more" or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions "at least one" or "one or more" will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once.
Further, as used in the following, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.
Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

Embodiment 1: A device for driving a fastener into a workpiece, preferably wherein the fastener is a nail, comprising:
- an air spring chamber, preferably wherein the air spring chamber is an air spring cylinder;
- a piston, wherein the piston is arranged within the air spring chamber in a manner that the piston is moveable from a ready position along a drive axis in order to force the fastener into the workpiece;
- a preload system, wherein the preload system is configured for preloading the device by forcing the piston in the ready position applying a preloading force;
wherein the preload system comprises
- ∘ a chain configured to transmit the preloading force to the piston or
- ∘ a hydraulic system configured to transmit the preloading force to the piston.
Embodiment 2: The device according to the preceding Embodiment, wherein the preload system comprises a lifting member, wherein the preload system transmits the preloading force to the piston via the lifting member.
Embodiment 3: The device according to any one of the preceding Embodiments, wherein, when the preload system comprises a chain, the device further comprises
- an electrically driven driving unit, wherein the electrically driven driving unit is configured to move the chain in order to move the piston along the drive axis.
Embodiment 4: The device according to any one of the preceding Embodiments, wherein, when the preload system comprises a chain, a portion of the chain that is outside of the air spring chamber is bent.
Embodiment 5: The device according to any one of the preceding Embodiments, wherein, when the preload system comprises a hydraulic system, the device further comprises
- a hydraulic pump, wherein the hydraulic pump is configured to generate a pressure in order to move the piston along the drive axis.
Embodiment 6: The device according to any one of the preceding Embodiments, wherein, when the preload system comprises a hydraulic system, the hydraulic system comprises a pipe, wherein a portion of the pipe that is outside of the air spring chamber is bent.
Embodiment 7: The device according to any one of the preceding Embodiments, wherein the preload system is configured to move the piston along the drive axis in a preload direction and in a fastening direction.
Embodiment 8: The device according to any one of the preceding Embodiments, wherein the preload system is fixedly attached to the piston.
Embodiment 9: The device according to any one of the preceding Embodiments 1 to 6, wherein the preload system is configured to decouple from the piston when the piston is in the ready position in a manner that the piston is moveable along the drive axis in order to force the fastener into the workpiece independent from the preload system.
Embodiment 10: The device according to the preceding Embodiment, further comprising:
- a retaining member, wherein the retaining member is configured to maintain the piston in the ready position.
Embodiment 11: The device according to any one of the preceding Embodiments, wherein the preload system at least partially runs through a further volume at least partially enclosed by the air spring chamber.
Embodiment 12: The device according to any one of the preceding Embodiments, further comprising:
- a driver that is fixedly attached to the piston, wherein the driver is forced against the fastener in a manner that the fastener is forced into a workpiece when the preloading of the device is released.
Embodiment 13: The device according to any one of the preceding Embodiments,
- a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber,
wherein, for preloading the device, the preload system is configured to decrease the pressurized volume in a manner that the pressure within the pressurized volume increases.
Embodiment 14: The device according to the preceding Embodiment, further comprising:
- an air flow regulating element, preferably wherein the air flow regulating element is a valve, wherein the air flow regulating element is configured to seal, in a closed position of the air flow regulating element, a first chamber compartment of the pressurized volume from a second chamber compartment of the pressurized volume.
Embodiment 15: The device according to the preceding Embodiment, wherein the air flow regulating element is further configured to enable, in an open position of the air flow regulating element, an air flow from the first chamber compartment into the second chamber compartment in order to drive the movement of the piston such that the fastener is forced into the workpiece, preferably wherein said movement of the piston causes the pressurized volume to increase.
Embodiment 16: The device according to the preceding Embodiment, further comprising:
- a piston; wherein the piston is configured for bringing the air flow regulating element from the closed position of the air flow regulating element in the open position of the air flow regulating element.
Embodiment 17: The device according to the preceding Embodiment, further comprising:
- a workpiece contact unit, wherein the workpiece contact unit is configured to move the plunger for bringing the air flow regulating element from the closed position of the air flow regulating element in the open position of the air flow regulating element when the workpiece contact unit contacts the workpiece.
Embodiment 18: A method for forcing a fastener into a workpiece, wherein the method comprises using a device according to any one of the preceding Embodiments, wherein the device is used to force a fastener into a workpiece.

Short description of the Figures

Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.
In the Figures:

Figure 1: shows an exemplary device for driving a fastener into a workpiece; and
Figure 2: shows a further exemplary device for driving a fastener into a workpiece.

Detailed description of the embodiments
In Figure 1 an exemplary device for driving a fastener into a workpiece is shown. The fastener may be a nail. The device 110 comprises:

an air spring chamber 112, preferably wherein the air spring chamber 112 is an air spring cylinder;
a piston 114, wherein the piston 114 is arranged within the air spring chamber 112 in a manner that the piston 114 is moveable from a ready position along a drive axis 140 in order to force the fastener into the workpiece;
a preload system 116, wherein the preload system 116 is configured for preloading the device by forcing the piston in the ready position applying a preloading force.

The preload system of the device 110 shown in Figure 1 comprises

∘ a chain 142 configured to transmit the preloading force to the piston 114.

As may be derived from the exemplary device 110 shown in Figure 2, the preload system 116 of the device 110 comprises alternatively

∘ a hydraulic system 150 configured to transmit the preloading force to the piston 114.

The preload system 116 at least partially may run through a further volume 166 at least partially enclosed by the air spring chamber 112.
Both devices 110 provide a particular robust preloading system of the device. Their advantage therefore is, in contrast to known preloading systems, that the wear of the device is minimized. In addition, the design of the device 110 may be more compact due to the flexibility offered by the chain 142 and the hydraulic system 150.
The device 110 may further comprise:

a driver 118 that is fixedly attached to the piston 114, wherein the driver 118 is forced against the fastener in a manner that the fastener is forced into a workpiece when the preloading of the device 110 is released.

The device 110 may further comprise:

a pressurized volume 120, wherein the pressurized volume 120 is at least partially formed by a pressure chamber 122,

The device 110 may further comprise:

an air flow regulating element 124, preferably wherein the air flow regulating element 124 is a valve, wherein the air flow regulating element 124 is configured to seal, in a closed position of the air flow regulating element 124, a first chamber compartment 126 of the pressurized volume 120 from a second chamber compartment 128 of the pressurized volume 120.

The air flow regulating element 124 may be further configured to enable, in an open position of the air flow regulating element 124, an air flow from the first chamber compartment 126 into the second chamber compartment 128 in order to drive the movement of the piston 114 such that the fastener is forced into the workpiece, preferably wherein said movement of the piston causes the pressurized volume 120 to increase.
In Figures 1 and 2 the air flow regulating element 124 is a valve and exemplary depicted in the closed position. In order to bring the air flow regulating element 124 in the open position, the air flow regulating element 124 may be pivotable via a joint 132.
The device may further comprise:

a plunger 130; wherein the plunger 130 is configured for bringing the air flow regulating element 124 from the closed position of the air flow regulating element 124 in the open position of the air flow regulating element 124.

The plunger 130 may pass through a pass-through 134 in the pressure chamber 122 into the pressurized volume 120. The plunger 130 may be movably arranged within the pass-through 134. Thereby, the plunger may be translationally moveable.
The device may further comprise:

a workpiece contact unit 136, wherein the workpiece contact unit 136 is configured to move the plunger 130 for bringing the air flow regulating element 124 from the closed position of the air flow regulating element 124 in the open position of the air flow regulating element 124 when the workpiece contact unit 136 contacts the workpiece.

The workpiece contact unit 136 may be configured to move the plunger 130 for bringing the air flow regulating element 124 from the closed position of the air flow regulating element 124 in the open position of the air flow regulating element 124 when the workpiece contact unit 136 is pressed against the workpiece. When the workpiece contact unit 136 is pressed against the workpiece 136, the workpiece contact unit 136 may move, specifically translationally move. Said movement may cause a movement of the plunger 130 required to bring the air flow regulating element 124 in the open position.
The device 110 may further comprise a stopper 170, specifically an elastic stopper, configured for stopping the piston 114, when the piston 114 is forced along the drive axis 140.
As may be derived from Figure 1 the chain 142 may comprise a contact member 148 that contacts the piston 114 in order to bring the piston 114 in the ready position and apply the preloading force.
When the preload system 116 comprises a chain, as exemplarily shown in Figure 1, the device 110 may further comprise

an electrically driven driving unit 138, wherein the electrically driven driving unit 138 is configured to move the chain 142 in order to move the piston along the drive axis 140.

The electrically driven driving unit 138 may be configured to bring the piston 114 in the ready position.
A portion of the chain 142 that is outside of the air spring chamber 112 may be bent, which may allow a compact design of the device 110.
As may be derived from Figure 1, the preload system 116 may be configured to decouple from the piston 114 when the piston 114 is in the ready position in a manner that the piston 114 is moveable along the drive axis 140 in order to force the fastener into the workpiece independent from the preload system 116.
Specifically in that scenario, the device 110 may further comprise:

a retaining member 144, wherein the retaining member 144 is configured to maintain the piston 114 in the ready position.

The device 110 may be configured to remove the retaining member 144 such that the piston 114 is no longer maintained the ready position in order trigger that the fastener is forced into the workpiece. To remove the retaining member a user may press a trigger 146 of the device 110.
The preload system 116 may be configured to move the piston along the drive axis 140 in a preload direction 162 and in a fastening direction 164, which may particularly be helpful in order to improve said independent movement of the piston 114. As exemplarily discussed for the device shown in Figure 1, the electrically driven driving unit 138 may be configured to pull the chain 142 out of the flight path of the piston 114 when piston 114 that is in the ready position. Consequently, when the piston is released by the retaining member 144 in order to force the fastener into the workpiece, the chain 142 does not impact the flight of the piston 114, such as by colliding with the piston 114. This applies accordingly when the preload system 116 comprises a hydraulic system 150 that can be decoupled from the piston 114.
Alternatively, the preload system 116 may be fixedly attached to the piston 114, as may be derived exemplarily from Figure 2.
When the preload system 116 comprises a hydraulic system 150, the device may further comprise

a hydraulic pump 152, wherein the hydraulic pump 152 is configured to generate a pressure in order to move the piston 114 along the drive axis 140.

The hydraulic system 150 may further comprise a hydraulic fluid container 154. The hydraulic system 150 may further comprise a 4-way-valve 156.
In a first position of the 4-way-valve 156, the hydraulic pump 152 that is in fluid connection with the hydraulic fluid container 154 may generate pressure so that the preloading force is applied to the piston 114. Therefore, fluid may be pumped out of the hydraulic fluid container 154 into a hydraulic cylinder 158 comprised by the hydraulic system 150. The piston may be coupled to the hydraulic cylinder 158 in a manner that the preloading force is transmitted to the piston 114. The preload system 116may comprise a lifting member 160, wherein the preload system 116 transmits a preloading force to the piston via the lifting member 160. The lifting member 160 may be received by the hydraulic cylinder 158. In a second position of the 4-way-valve 154, the piston 114 can move in the fastening direction 164.
The fluid connection may be established via at least one pipe 168 of the hydraulic system 150. A portion of the pipe 168 that is outside of the air spring chamber 112 may be bent.

List of reference numbers

110: device for driving a fastener into a workpiece
112: air spring chamber
114: piston
116: preload system
118: driver
120: pressurized volume
122: pressure chamber
124: air flow regulating element
126: first chamber compartment
128: second chamber compartment
130: plunger
132: joint
134: pass-through
136: workpiece contact unit
138: electrically driven driving unit
140: drive axis
142: chain
144: retaining member
146: trigger
148: contact member
150: hydraulic system
152: hydraulic pump
154: hydraulic fluid container
156: 4-way-valve
158: hydraulic cylinder
160: lifting member
162: preload direction
164: fastening direction
166: further volume
168: pipe
170: stopper

Claims

A device (110) for driving a fastener into a workpiece, preferably wherein the fastener is a nail, comprising:
- an air spring chamber (112), preferably wherein the air spring chamber (112) is an air spring cylinder;

- a piston (114), wherein the piston (114) is arranged within the air spring chamber (112) in a manner that the piston (114) is moveable from a ready position along a drive axis (140) in order to force the fastener into the workpiece;

- a preload system (116), wherein the preload system (116) is configured for preloading the device (110) by forcing the piston (114) in the ready position applying a preloading force;
wherein the preload system (116) comprises
∘ a chain (142) configured to transmit the preloading force to the piston (114) or

∘ a hydraulic system (150) configured to transmit the preloading force to the piston (114).
The device (110) according to the preceding claim, wherein the preload system (116) comprises a lifting member (160), wherein the preload system (116) transmits the preloading force to the piston (114) via the lifting member (160).
The device (110) according to any one of the preceding claims, wherein, when the preload system (116) comprises a chain (142), the device (110) further comprises
- an electrically driven driving unit (138), wherein the electrically driven driving unit (138) is configured to move the chain (142) in order to move the piston (114) along the drive axis.
The device (110) according to any one of the preceding claims, wherein, when the preload system (116) comprises a chain (142), a portion of the chain (142) that is outside of the air spring chamber (112) is bent.
The device (110) according to any one of the preceding claims, wherein, when the preload system (116) comprises a hydraulic system (150), the device (110) further comprises
- a hydraulic pump (152), wherein the hydraulic pump (152) is configured to generate a pressure in order to move the piston (114) along the drive axis.
The device (110) according to any one of the preceding claims, wherein, when the preload system (116) comprises a hydraulic system (150), the hydraulic system (150) comprises a pipe (168), wherein a portion of the pipe (168) that is outside of the air spring chamber (112) is bent.
The device (110) according to any one of the preceding claims, wherein the preload system (116) is configured to move the piston (114) along the drive axis in a preload direction (162) and in a fastening direction (164).
The device (110) according to any one of the preceding claims, wherein the preload system (116) is fixedly attached to the piston (114).
The device (110) according to any one of the preceding claims 1 to 6, wherein the preload system (116) is configured to decouple from the piston (114) when the piston (114) is in the ready position in a manner that the piston (114) is moveable along the drive axis (140) in order to force the fastener into the workpiece independent from the preload system (116).
The device (110) according to the preceding claim, further comprising:
- a retaining member (144), wherein the retaining member (144) is configured to maintain the piston (114) in the ready position.
The device (110) according to any one of the preceding claims, wherein the preload system (116) at least partially runs through a further volume (166) at least partially enclosed by the air spring chamber (112).
The device (110) according to any one of the preceding claims, further comprising:
- a driver (118) that is fixedly attached to the piston (114), wherein the driver (118) is forced against the fastener in a manner that the fastener is forced into a workpiece when the preloading of the device (110) is released.
The device (110) according to any one of the preceding claims,
- a pressurized volume (120), wherein the pressurized volume (120) is at least partially formed by a pressure chamber (122),
wherein, for preloading the device (110), the preload system (116) is configured to decrease the pressurized volume (120) in a manner that the pressure within the pressurized volume (120) increases.
The device (110) according to the preceding claim, further comprising:
- an air flow regulating element (124), preferably wherein the air flow regulating element (124) is a valve, wherein the air flow regulating element (124) is configured to seal, in a closed position of the air flow regulating element (124), a first chamber compartment (126) of the pressurized volume (120) from a second chamber compartment (128) of the pressurized volume (120).
A method for forcing a fastener into a workpiece, wherein the method comprises using a device (110) according to any one of the preceding claims, wherein the device (110) is used to force a fastener into a workpiece.