EP4686530A1

EP4686530A1 - A device and a method for driving a fastener into a workpiece

Info

Publication number: EP4686530A1
Application number: EP24192017.2A
Authority: EP
Inventors: Bernhard Andreas Hormann; Joerg Stamm; Mario Zahner; Eric Schulte Suedhoff
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2024-07-31
Filing date: 2024-07-31
Publication date: 2026-02-04
Also published as: WO2026037569A1

Abstract

A device (110) for driving a fastener into a workpiece comprising:
- an air spring chamber (112);
- a piston (114), wherein the piston (114) is arranged within the air spring chamber (112) in a manner that the piston (114) is moveable along a drive axis (130);
- a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber (120);
- an air flow regulating element (124), 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 from a second chamber compartment (128) of the pressurized volume;
- an electrically driven driving unit (136) for the air flow regulating element (124);
wherein the electrically driven driving unit (136) is configured for bringing the air flow regulating element (124) from the closed position of the air flow regulating element (124) in at least one open position of the air flow regulating element (124).

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 to more precisely define force generated by the device to driving the fastener into a workpiece. In particular, it may be an object of the present invention to prevent wear of the components of the device.

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 along a drive axis, preferably wherein the air spring chamber and a first wall of the piston at least partially form a further volume;
a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber, preferably wherein the pressurized volume is further at least partially formed by a second wall of the piston;
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;
- ∘ optionally wherein the air flow regulating element may be configured to enable, in at least one open position, an air flow from the first chamber compartment into the second chamber compartment in order to drive the movement of the piston such that a driver that is fixedly attached to the piston is forced against a fastener in a manner that the fastener is forced into a workpiece, preferably wherein said movement of the piston causes the pressurized volume to increase and the further volume to decrease;
an electrically driven driving unit for the air flow regulating element; wherein the electrically driven driving unit is configured for bringing the air flow regulating element from the closed position of the air flow regulating element in at least one open position of the air flow regulating element.

The term "air spring chamber" may refer to chamber configured for supporting a 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 term "pressurized volume" may refer to volume formed by at least the pressure chamber and the second wall of the piston. A pressure within the pressurized volume that is minimized may be, typically, larger than 4 bar. The device may comprise an air accumulator. The air accumulator may be configured to pressurize the pressurized volume.
When the air flow regulating element is in a closed position, it separates 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. Therefore, the second chamber compartment be at least partially formed by the second wall of the piston. 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.
A preload driving unit may be configured to hold the piston in a ready position against the pressure caused by the air in the pressurized volume. In order to the drive the movement of the piston such that the driver that is fixedly 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 preload driving unit may be configured to release the force retaining the piston in the ready position. This causes the air within the pressurized volume to expand abruptly and, thereby, move the piston.
The movement of the piston may cause the driver to move in the fastening direction. Thereby, the further volume may decrease, which may, typically, allow gaseous exchange with the environment, typically air. The gaseous exchange may be allowed via openings 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 fastener 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 term "electrically driven driving unit" may refer to a device configured to convert electrical energy into a mechanical movement and/or a force. The device may comprise a battery configured to provide the electrical energy to the electrically driven driving unit. In order to generate the mechanical movement and/or the force, the electrically driven driving unit may be or may comprise an electrical motor and/or a coil. The electrical motor and/or the coil may be activated in order move an actuator that is fixedly attached to the air flow regulating element in order to bring the air flow regulating element into a specific position.
Using an electrically driven driving unit may have the advantage that the air flow regulating element can be brought into the open position more precisely and with a precisely defined force. This may prevent wear of the components of the device and the air flow regulating element in particular.
The device further may comprise a sensing unit. The sensing unit may be a hall sensor and/or a switch. The sensing unit may be configured for triggering the electrically driven driving unit to bring the air flow regulating element from the closed position of the air flow regulating element in the at least one open position of the air flow regulating element when the sensing unit detects that the device is in contact with the workpiece.
Using a sensing unit may have the advantage that the electrically driven driving unit may be activated without a mechanical contact applied to the electrically driven driving unit. This may prevent wear of the components of the device and the electrically driven driving unit in particular.
The device further may comprise a workpiece contact unit. For the sensing unit to detect that the device, specifically a work contact element, is in contact with the workpiece, the workpiece contact unit may be movable relative to the sensing unit and the sensing unit may be configured to detect the relative movement. The user may contact the workpiece with a work contact element configured to guide the fastener into the workpiece. Typically, the work contact element may be a fastener guide for the fastener. The length of the work contact element may be adjustable in order to regulate the penetration depth of the fastener within the workpiece. When the user contact the workpiece with the work contact element, the user may bring the workpiece contact unit from a contactless position into a contact position and, thereby, move the workpiece relative to the sensing unit. This relative movement may be detected by the sensing unit. When said movement is detected, the sensing unit may trigger the electrically driven driving unit to bring the air flow regulating element from the closed position of the air flow regulating element in the at least one open position of the air flow regulating element.
Using a sensing unit to detect a relative movement of the workpiece contact unit may have the advantage that this presents an easy and cost-efficient solution to activate the electrically driven driving unit. Further, the workpiece contact unit may not be required to penetrate within the pressurized volume with the effect that the pressurized volume may be sealed more efficiently.
The at least one open position of the air flow regulating element may be variable. The at least one open position of the air flow regulating element may comprise a plurality of differing open positions. The differing positions each may cause a differing air flow resistance for the air flow from the first chamber compartment into the second chamber compartment. Thereby, the electrically driven driving unit may be configured for bringing the air flow regulating element in a selected open position of the plurality of differing open positions.
Using a variable at least one open position in order to cause a differing air flow resistance for the air flow from the first chamber compartment into the second chamber compartment may have the advantage that the force applied to force the fastener into the workpiece and/or the energy level related to the force applied to force the fastener into the workpiece can be adjusted and/or set.
The device may comprise a user input unit. Said user input unit may be configured to receive the selected open position and cause the electrically driven driving unit to bring the air flow regulating element in said selected open position. In order to select the open position, the user may input an operational parameter. The operational parameter may be or may comprise the open position or the operational parameter may be associated with and/or related to the open position. An operational parameter that is associated with and/or related to the open position may be or may comprise an energy level related to the force applied to force the fastener into the workpiece. The operational parameter that is associated with and/or related to the open position may be converted into the open position by the user input unit.
Using a user input unit to select to open position may have the advantage that the force applied to force the fastener into the workpiece can be set by the user. Thereby, the force applied to force the fastener into the workpiece and/or the energy level related to the force applied to force the fastener into the workpiece can be customized by the user to match the desired penetration depth of the fastener into a specific workpiece.
The electrically driven driving unit for the air flow regulating element may be further configured for bringing the air flow regulating element from the at least one open position in the closed position after expiry of an opening time of the air flow regulating element. Preferably, when the electrically driven driving unit air flow regulating element may be further configured for bringing the air flow regulating element from the at least one open position in the closed position after expiry of an opening time of the air flow regulating element. The electrically driven driving unit for the air flow regulating element may be arranged within the pressurized volume.
Using the electrically driven driving unit for air flow regulating element for bringing the air flow regulating element from the at least one open position in the closed position after expiry of an opening time may have the advantage of controlling the force applied to force the fastener into the workpiece and/or the energy level related to the force applied to force the fastener into the workpiece, since the air flow from the first chamber compartment into the second chamber compartment may be actively stopped.
The opening time may be a variable opening time. The device may comprise a further user input unit. Thereby, the further user input unit may be configured to receive the variable opening time of the air flow regulating element and cause the electrically driven driving unit to bring the air flow regulating element from the at least one open position in the closed position after expiry of the received variable opening time. In order to select the opening time, the user may input a further operational parameter. The further operational parameter may be or may comprise the opening time or the further operational parameter may be associated with and/or related to the opening time. A further operational parameter that is associated with and/or related to the opening time may be or may comprise an energy level related to the force applied to force the fastener into the workpiece. The further operational parameter that is associated with and/or related to the opening time may be converted into the open position by the further user input unit.
Using a variable opening time may have the advantage that the force applied to force the fastener into the workpiece and/or the energy level related to the force applied to force the fastener into the workpiece can be adjusted by the user to match the desired penetration depth of the fastener into a specific workpiece.
The user input unit and the further user input unit may be a common user input unit. For selecting the open position and the opening time, the user may input a common operational parameter. The common operational parameter may be associated with and/or related to the open position and the common operational parameter may be associated with and/or related to the opening time. Exemplarily, the common operational parameter may be or may comprise an energy level related to the force applied to force the fastener into the workpiece. The common operational parameter may be converted into the selected open position and the opening time by the common user input unit.
The device further may comprise at least one detection device. The detection device may be an optical sensor, a magnetic field sensor, specifically a Giant Magnetoresistance (GMR) sensor and/or a hall sensor. The detection device may be configured for detecting a position of the piston and/or a velocity of the piston at least partially while the piston is moved to force the fastener into the workpiece. The velocity of the piston may be determined by evaluating a plurality of positions and a time stamp related to each position of the plurality of positions. The device further may comprise a control unit for controlling the electrically driven driving unit for the air flow regulating element based on the position of the piston and/or the velocity of the piston. For controlling the electrically driven driving unit, the control unit may be configured to at least one of: setting the opening position of the air flow resistance element; setting the opening time of the air flow resistance element.
The control unit may be configured to control the air flow resistance element in a manner that the energy level related to the force applied to force the fastener into the workpiece is maintained constant, preferably over the lifetime of the device. Thereby, it may be ensured that device works reliably over an extended period of time.
The control unit may be configured to control the air flow resistance element in a manner that the opening time is adjusted based on the detected position of the piston and/or the detected velocity of the piston in order to match an expected position of the piston and/or an expected velocity of the piston, wherein the expected position of the piston and/or the expected velocity of the piston may be dependent on the energy level related to the force applied to force the fastener into the workpiece received by the user input unit.
The control unit may be configured to control the air flow resistance element in a manner that the opening time is adjusted based on the detected position of the piston and/or the detected velocity of the piston in order to match an expected position of the piston and/or an expected velocity of the piston, wherein the expected position of the piston and/or the expected velocity of the piston may be dependent on an expected penetration depth of the fastener in the workpiece.
The electrically driven driving unit may be further configured for keeping the air flow regulating element in the at least one open position. The device may comprise a position holding device configured to keep the air flow regulating element in the at least one open position.
Using the electrically driven driving unit for keeping the air flow regulating element in the at least one open position may have the advantage of controlling the force applied to force the fastener into the workpiece and/or the energy level related to the force applied to force the fastener into the workpiece, since the air flow from the first chamber compartment into the second chamber compartment may be actively be remained.
The position holding device may comprise an electromagnet. The electromagnet may be configured to keep the air flow regulating element in the at least one open position when activated. Thereby, the position holding device may comprise a magnetic element or a permamagnet, wherein the magnetic element or the permamagnet may be configured to be attracted by the activated electromagnet. Such a composition of components may be cost efficient.
The electrically driven driving unit for the air flow regulating element may be arranged within the pressurized volume. The electrically driven driving unit for the air flow regulating element may be an electrical driving unit.
Arranging the electrically driven driving unit for the air flow regulating element within the pressurized volume may have the advantage of preventing wear of the components of the device. In contrast to a solution wherein the electrically driven driving unit for the air flow regulating element may be arranged outside of the pressurized volume no seal for the actuator contacting the air flow regulating element is required.
The electrically driven driving unit for the air flow regulating element may be an electrical driving unit. The electrically driven driving unit for the air flow regulating element may be a magnetic driving unit. The magnetic driving unit may comprise a coil, wherein the coil is configured to move an actuator in order to bring the air flow regulating element in a position. Such a composition of components may be cost efficient.
The device may comprise a preload driving unit. The preload driving unit may be configured for preloading the device by forcing the piston in a ready position into which the piston is moved in a manner that the pressurized volume, specifically a volume of the second chamber compartment, is decreased. The preload driving unit may be an electrically driven preload driving unit. The preload driving unit may be used as the electrically driven driving unit for the air flow regulating element. The device may comprise a contact piece, preferably fixedly attached to the air flow regulating element or the piston. The contact piece may be configured to bring the air flow regulating element from the closed position in the at least one open position when the preloading of the device is released. Preferably, wherein the contact piece contacts the air flow regulating element and/or the piston in order to bring the air flow regulating element from the closed position in the at least one open position. Such a composition of components may be cost efficient, since a separate electrically driven preload driving unit for the air flow regulating element is not required.
The device further may comprise a gear wheel comprising a first segment comprising a plurality of teeth and a second segment being free of teeth. The preload driving unit may be configured to drive a rotation of the gear wheel in a rotation direction.
The device further may comprise a rack comprising a plurality of rollers. The rack may be fixedly attached to the piston such that a movement of the rack may cause a movement of the piston. The plurality of rollers may be engaged by the teeth such that the rotation of the gear wheel may cause a movement of the rack in a preload direction until the piston is in the ready position. In the ready position a roller of the rack may engage a last tooth of the first segment that is arranged at a transition to the second segment. The segments may be arranged next to each other in a circumferential direction defined by the gear wheel.
In order to release the preloading of the device, the electrically driven driving unit may be configured to further drive the gear wheel in the rotation direction causing a further movement of the piston in the preload direction until the gear wheel no longer engages the rack such that the preload of the device releases and the piston is forced in a fastening direction. The further movement of the rack in the preload direction may cause the contact of the contact piece and the piston and, thereby, may bring the air flow regulating element from the closed position in at least one open position when the preloading of the device is released.
In a further aspect, a method for forcing a fastener into a workpiece is disclosed, wherein the method comprises using a device as elsewhere described herein, 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 along a drive axis, preferably wherein the air spring chamber and a first wall of the piston at least partially form a further volume;
- a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber, preferably wherein the pressurized volume is further at least partially formed by a second wall of the piston;
- 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;
  - ∘ optionally wherein the air flow regulating element is configured to enable, in at least one open position, an air flow from the first chamber compartment into the second chamber compartment in order to drive the movement of the piston such that a driver that is fixedly attached to the piston is forced against a fastener in a manner that the fastener is forced into a workpiece, preferably wherein said movement of the piston causes the pressurized volume to increase and the further volume to decrease;
- an electrically driven driving unit for the air flow regulating element; wherein the electrically driven driving unit is configured for bringing the air flow regulating element from the closed position of the air flow regulating element in at least one open position of the air flow regulating element.
Embodiment 2. The device according to the preceding Embodiment, wherein the device further comprises a sensing unit, preferably wherein the sensing unit is at least one of: a hall sensor; a switch, wherein the sensing unit is configured for triggering the electrically driven driving unit to bring the air flow regulating element from the closed position of the air flow regulating element in the at least one open position of the air flow regulating element when the sensing unit detects that the device is in contact with the workpiece.
Embodiment 3. The device according to the preceding Embodiment, wherein the device further comprises a workpiece contact unit, wherein, for the sensing unit to detect that the device, specifically a work contact element, is in contact with the workpiece, the workpiece contact unit is movable relative to the sensing unit and the sensing unit is configured to detect the relative movement.
Embodiment 4. The device according to any one of the preceding Embodiments, wherein the at least one open position of the air flow regulating element is variable, wherein the at least one open position comprises a plurality of differing open positions, wherein the differing positions each cause a differing air flow resistance for the air flow from the first chamber compartment into the second chamber compartment, wherein the electrically driven driving unit is configured for bringing the air flow regulating element in a selected open position of the plurality of differing open positions.
Embodiment 5. The device according to the preceding Embodiment, wherein the device comprises a user input unit, wherein the user input unit is configured to receive the selected open position and cause the electrically driven driving unit to bring the air flow regulating element in said selected open position.
Embodiment 6. The device according to any one of the preceding Embodiments, wherein the electrically driven driving unit for the air flow regulating element is further configured for bringing the air flow regulating element from the at least one open position in the closed position after expiry of an opening time of the air flow regulating element.
Embodiment 7. The device according to the preceding Embodiment,
- wherein the opening time is a variable opening time, wherein the device comprises a further user input unit, wherein the further user input unit is configured to receive the variable opening time of the air flow regulating element and cause the electrically driven driving unit to bring the air flow regulating element from the at least one open position in the closed position after expiry of the received variable opening time;
- wherein the opening time is a predetermined opening time.
Embodiment 8. The device according to any one of the preceding Embodiments, wherein the device further comprises at least one detection device, wherein the detection device is configured for detecting at least one of: a position; a velocity of the piston at least partially while the piston is moved to force the fastener into the workpiece.
Embodiment 9. The device according to the preceding Embodiment, wherein the device further comprises a control unit for controlling the electrically driven driving unit based on at least one of: the position of the piston; the velocity of the piston.
Embodiment 10. The device according to the preceding Embodiment, wherein the control unit is configured to control the air flow resistance element in a manner that the opening time is adjusted based on the detected position of the piston and/or the detected velocity of the piston in order to match an expected position of the piston and/or an expected velocity of the piston, wherein the expected position of the piston and/or the expected velocity of the piston dependent on the energy level related to the force applied to force the fastener into the workpiece received by the user input unit.
Embodiment 11. The device according to the any one of the two preceding Embodiments, wherein the control unit is configured to control the air flow resistance element in a manner that the opening time is adjusted based on the detected position of the piston and/or the detected velocity of the piston in order to match an expected position of the piston and/or an expected velocity of the piston, wherein the expected position of the piston and/or the expected velocity of the piston dependent on an expected penetration depth of the fastener in the workpiece.
Embodiment 12. The device according to any one of the preceding Embodiments, wherein the electrically driven driving unit is further configured for keeping the air flow regulating element in the at least one open position.
Embodiment 13. The device according to any one of the preceding Embodiments 1 to 11, wherein the device comprises a position holding device configured to keep the air flow regulating element in the at least one open position.
Embodiment 14. The device according to the preceding Embodiment, wherein the position holding device comprises an electromagnet, wherein the electromagnet is configured to keep the air flow regulating element in the at least one open position when activated, wherein the position holding device comprises a magnetic element or a permamagnet, wherein the magnetic element or the permamagnet is configured to be attracted by the activated electromagnet.
Embodiment 15. The device according to any one of the preceding Embodiments, wherein the electrically driven driving unit for the air flow regulating element is arranged within the pressurized volume.
Embodiment 16. The device according to any one of the preceding Embodiments, wherein the electrically driven driving unit for the air flow regulating element is an electrical driving unit.
Embodiment 17. The device according to any one of the preceding Embodiments, wherein the electrically driven driving unit for the air flow regulating element is a magnetic driving unit.
Embodiment 18. The device according to any one of the preceding Embodiments, wherein the device comprises a preload driving unit, wherein the preload driving unit is configured for preloading the device by forcing the piston in a ready position into which the piston is moved in a manner that the pressurized volume, specifically a volume of the second chamber compartment, is decreased.
Embodiment 19. The device according to the preceding Embodiment, wherein the preload driving unit is used as the electrically driven driving unit for the air flow regulating element, wherein the device comprises a contact piece fixedly attached to the air flow regulating element or the piston, preferably wherein the contact piece is configured to bring the air flow regulating element from the closed position in the at least one open position when the preloading of the device.
Embodiment 20. The device according to the preceding Embodiment,
- wherein the device further comprises a gear wheel comprising a first segment comprising a plurality of teeth and a second segment being free of teeth, wherein the preload driving unit is configured to drive a rotation of the gear wheel in a rotation direction;
- wherein the device further comprises a rack comprising a plurality of rollers, wherein the rack is fixedly attached to the piston such that a movement of the rack causes a movement of the piston, wherein the plurality of rollers is engaged by the teeth such that the rotation of the gear wheel causes a movement of the rack in a preload direction until the piston is in the ready position, wherein, in the ready position a roller of the rack engages a last tooth of the first segment that is arranged at a transition to the second segment;
- wherein, in order to release the preloading of the device, the electrically driven driving unit is configured to further drive the gear wheel in the rotation direction causing a further movement of the piston in the preload direction until the gear wheel no longer engages the rack such that the preload of the device releases and the piston is forced in a fastening direction, wherein the further movement of the rack in the preload direction causes the contact of the contact piece and the piston and, thereby, brings the air flow regulating element from the closed position in at least one open position when the preloading of the device is released.
Embodiment 21. The device according to any one of the preceding Embodiments, wherein the device comprises an air accumulator, wherein the air accumulator is configured to pressurize the pressurized volume.
Embodiment 22. 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 a device for driving a fastener into a workpiece with an air flow regu-lating element in a closed position; and
Figure 2: shows the device for driving the fastener into the workpiece with the air flow regulating element in an open position;
Figure 3: shows a further device for driving a fastener into a workpiece;
Figure 4: shows a further device for driving a fastener into a workpiece;
Figure 5: shows a further device for driving a fastener into a workpiece; and
Figure 6: shows a further device for driving a fastener into a workpiece.

Detailed description of the embodiments

In Figure 1, a device 110 for driving a fastener into a workpiece is shown. The device 110 comprises an air spring chamber 112, preferably wherein the air spring chamber 112 is an air spring cylinder. Further, the device 110 comprises a piston 114, wherein the piston 114 is arranged within the air spring chamber 112 in a manner that the piston 114 is moveable along a drive axis 130, preferably wherein the air spring chamber 112 and a first wall 116 of the piston 114 at least partially form a further volume 118. The device 110 may comprise a seal configure to seal the piston against the air spring chamber 112.
The piston 114 may be moved in a preload direction 132 and a fastening direction 134. Further, the device 110 comprises a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber 120, preferably the pressurized volume is further at least partially formed by a a second wall 122 of the piston 114. The device 110 may comprise an air accumulator 154, wherein the air accumulator is configured to pressurize the pressurized volume.
Further, the device 110 comprises an air flow regulating element 124. As depicted in Figure 1, the air flow regulating element 124 may be a valve. 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 and a second chamber compartment 128 of the pressurized volume. In Figure 1, the air flow regulating element 124 is shown in the closed position.
Figure 2 shows the device 110 for driving a fastener into a workpiece of Figure 1. As may be derived from Figure 1, the air flow regulating element 124 may be configured to enable, in at least one open position (depicted in Figure 2), 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 a driver 150 that is fixedly attached to the piston 114 is forced against a fastener in a manner that the fastener is forced into a workpiece, preferably wherein said movement of the piston 114 causes the pressurized volume to increase and the further volume 118 to decrease. As may exemplarily be derived from Figure 2, the fastener may be an integral part of the piston 114. The driver 150 may be arranged within a work contact element 152.
The at least one open position of the air flow regulating element 124 may be variable. The at least one open position may comprise a plurality of differing open positions, wherein the differing positions each cause a differing air flow resistance for the air flow from the first chamber compartment 126 into the second chamber compartment 128, wherein the electrically driven driving unit 136 is configured for bringing the air flow regulating element 124 in a selected open position of the plurality of differing open positions. The device 110 may comprise a user input unit 142, wherein the user input unit 142 is configured to receive the selected open position and cause the electrically driven driving unit 136 to bring the air flow regulating element 124 in said selected open position.
Further, the device 110 comprises an electrically driven driving unit 136 for the air flow regulating element 124; wherein the electrically driven driving unit 136 is configured for bringing the air flow regulating element 124 from the closed position of the air flow regulating element 124 in at least one open position of the air flow regulating element 124. The electrically driven driving unit 136 for the air flow regulating element 124 may be an electrical driving unit, as depicted in Figure 1. The electrical driving unit may move an actuator 160 in order to bring or keep the air flow regulating element 124 in a position.
The device 110 further may comprise a sensing unit 138, wherein the sensing unit 138 may be configured for triggering the electrically driven driving unit 136 to bring the air flow regulating element 124 from the closed position of the air flow regulating element 124 in the at least one open position of the air flow regulating element 124 when the sensing unit 138 detects that the device 110 is in contact with the workpiece.
The device 110 further may comprise a workpiece contact unit 140, wherein, for the sensing unit 138 to detect that the device 110, specifically the work contact element 152, is in contact with the workpiece, the workpiece contact unit 140 is movable relative to the sensing unit 138 and the sensing unit 138 is configured to detect the relative movement. The workpiece contact unit 140 may be moveable parallel to the drive axis 130.
The electrically driven driving unit 136 for the air flow regulating element 124 may be further configured for bringing the air flow regulating element 124 from the at least one open position in the closed position after expiry of an opening time of the air flow regulating element 124.
The opening time may be a variable opening time, wherein the device 110 comprises a further user input unit 144, wherein the further user input unit 144 is configured to receive the variable opening time of the air flow regulating element 124 and cause the electrically driven driving unit 136 to bring the air flow regulating element 124 from the at least one open position in the closed position after expiry of the received variable opening time. As may be derived from Figure 1, the user input unit 142 and the further user input unit 144 may be a common input unit. In order to selected the open position and the opening time of the air flow regulating element 124 the user may set a common operational parameter, e.g. an energy level related to the force applied to force the fastener into the workpiece. The common operational parameter may be converted into the selected open position and the opening time by the further user input unit 144. Alternatively, the opening time may be a predetermined opening time.
The device 110 further may comprise at least one detection device 146, wherein the detection device 146 is configured for detecting at least one of: a position; a velocity of the piston 114 at least partially while the piston 114 is moved to force the fastener into the workpiece. The device 110 further may comprise a control unit 148 for controlling the electrically driven driving unit 136 based on at least one of: the position of the piston 114; the velocity of the piston 114.
The device 110 may comprise a preload driving unit 156, wherein the preload driving unit 156 is configured for preloading the device 110 by forcing the piston 114 in a ready position (as depicted in Figure 1) into which the piston 114 is moved in a manner that the pressurized volume, specifically a volume of the second chamber compartment 128, is decreased. In order to force the driver 150 that is fixedly attached to the piston 114 against the fastener in a manner that the fastener is forced into a workpiece, the preload pressure has to be released. The device 110 may comprise a trigger 158 that is configured to release the preload pressure by a user input.
The electrically driven driving unit 136 may be further configured for keeping the air flow regulating element 124 in the at least one open position.
Figure 3 shows a further device 110 for driving a fastener into a workpiece. As may be derived from Figure 3, the electrically driven driving unit 136 for the air flow regulating element 124 may be arranged within the pressurized volume. In this case, only wire feed-throughs need to be routed into the pressurized volume. Alternatively or in addition, a portion of the air spring chamber 112 and/or the pressure chamber 120 may be conductive in order to constitute an electrical contact. This may improves the sealing of the pressurized volume against the environment.
Figure 4 shows a further device 110 for driving a fastener into a workpiece. As may be derived from Figure 4, the electrically driven driving unit 136 for the air flow regulating element 124 may be arranged within the pressurized volume.. The electrically driven driving unit 136 for the air flow regulating element 124 may be a magnetic driving unit. The magnetic driving unit may comprise a coil, wherein the coil moves the actuator 160 in order to bring the air flow regulating element 124 in a position.
Figure 5 shows a further device 110 for driving a fastener into a workpiece. As may be derived from Figure 4, the electrically driven driving unit 136 for the air flow regulating element 124 may be arranged within the pressurized volume.
Figure 6 shows a further device 110 for driving a fastener into a workpiece. As already indicated, the device 110 may comprise a preload driving unit 156, wherein the preload driving unit 156 is configured for preloading the device 110 by forcing the piston 114 in a ready position into which the piston 114 is moved in a manner that the pressurized volume, specifically a volume of the second chamber compartment 128, is decreased.
As may be derived from Figure 6, the preload driving unit 156 may be used as the electrically driven driving unit 136 for the air flow regulating element 124, preferably wherein the device 110 comprises a contact piece 162 fixedly attached to the air flow regulating element 124 or the piston 114, wherein the contact piece 162 is configured to bring the air flow regulating element 124 from the closed position in at least one open position when the preloading of the device 110 is released. Alternatively, the contact piece 162 may be fixedly attached to the piston 114.
Particularly therefore, the device 110 further may comprise a gear wheel 164 comprising a first segment 166 comprising a plurality of teeth 168 and a second segment 170 being free of teeth 168, wherein the preload driving unit 156 is configured to drive a rotation of the gear wheel 164 in a rotation direction 172.
The device 110 further may comprise a rack 174 comprising a plurality of rollers 176, wherein the rack 174 is fixedly attached to the piston 114 such that a movement of the rack 174 causes a movement of the piston 114, wherein the plurality of rollers 176 is engaged by the teeth 168 such that the rotation of the gear wheel 164 causes a movement of the rack 174 in a preload direction 132 until the piston 114 is in the ready position (as depicted in Figure 6), wherein, in the ready position a roller of the rack engages a last tooth 188 of the first segment 166 that is arranged at a transition to the second segment 170. The rack 174 may be an integral part of the piston 114.
In order to release the preloading of the device 110, the electrically driven driving unit 136 may be configured to further drive the gear wheel 164 in the rotation direction 172 causing a further movement of the piston 114 in the preload direction 132 until the gear wheel 164 no longer engages the rack 174 such that the preload of the device 110 releases and the piston 114 is forced in a fastening direction 134, wherein the further movement of the rack 174 in the preload direction 132 causes the contact of the contact piece 162 and the piston 114 and, thereby, brings the air flow regulating element 124 from the closed position in at least one open position when the preloading of the device 110 is released.
The device 110 may comprise a position holding device 178 configured to keep the air flow regulating element 124 in the at least one open position. The position holding device 178 may comprises an electromagnet 180, wherein the electromagnet is configured to keep the air flow regulating element 124 in the at least one open position when activated, wherein the position holding device 178 may comprise a magnetic element 182 or a permamagnet 184, wherein the magnetic element 182 or the permamagnet 184 may be configured to be attracted by the activated electromagnet. The device 110 may further comprise a spring 186 configured to bring the air flow regulating element 124 into the closed position.
As may be particularly derived from Figure 9, the device 110 may comprise an elastic damping element configured to securely receive and decelerate the driven piston 114.

List of reference numbers

110: device
112: air spring chamber
114: piston
116: first wall
118: further volume
120: pressure chamber
122: second wall
124: air flow regulating element
126: first chamber compartment
128: second chamber compartment
130: drive axis
132: preload direction
134: fastening direction
136: electrically driven driving unit
138: sensing unit
140: workpiece contact unit
142: user input unit
144: further user input unit
146: detection device
148: control unit
150: driver
152: work contact element
156: preload driving unit
158: trigger
160: actuator
162: contact piece
164: gear wheel
166: first segment
168: tooth
170: second segment
172: rotation direction
174: rack
176: roller
178: position holding device
180: electromagnet
182: magnetic element
184: permamagnet
186: Spring
188: seal
190: damping element

Claims

A device (110) for driving a fastener into a workpiece comprising:
- an air spring chamber (112);

- a piston (114), wherein the piston (114) is arranged within the air spring chamber (112) in a manner that the piston (114) is moveable along a drive axis (130);

- a pressurized volume, wherein the pressurized volume is at least partially formed by a pressure chamber (120);

- an air flow regulating element (124), 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 from a second chamber compartment (128) of the pressurized volume;

- an electrically driven driving unit (136) for the air flow regulating element (124);
wherein the electrically driven driving unit (136) is configured for bringing the air flow regulating element (124) from the closed position of the air flow regulating element (124) in at least one open position of the air flow regulating element (124).
The device (110) according to the preceding claim, wherein the air flow regulating element (124) is further configured to enable, in the at least one open position, 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 a driver (150) that is fixedly attached to the piston (114) is forced against a fastener in a manner that the fastener is forced into a workpiece.
The device (110) according to any one of the preceding claims, wherein the device (110) further comprises a sensing unit (136), wherein the sensing unit (136) is configured for triggering the electrically driven driving unit (136) to bring the air flow regulating element (124) from the closed position of the air flow regulating element (124) in the at least one open position of the air flow regulating element (124) when the sensing unit (136) detects that the device (110) is in contact with the workpiece.
The device (110) according to the preceding claim, wherein the device (110) further comprises a workpiece contact unit (140), wherein, for the sensing unit (136) to detect that the device (110) is in contact with the workpiece, the workpiece contact unit (140) is movable relative to the sensing unit (136) and the sensing unit (136) is configured to detect the relative movement.
The device (110) according to any one of the preceding claims, wherein the at least one open position of the air flow regulating element (124) is variable, wherein the at least one open position of the air flow regulating element (124) comprises a plurality of differing open positions, wherein the differing positions each cause a differing air flow resistance for the air flow from the first chamber compartment (126) into the second chamber compartment (128), wherein the electrically driven driving unit (136) is configured for bringing the air flow regulating element (124) in a selected open position of the plurality of differing open positions.
The device (110) according to the preceding claim, wherein the device (110) comprises a user input unit, wherein the user input unit is configured to receive the selected open position and cause the electrically driven driving unit (136) to bring the air flow regulating element (124) in said selected open position.
The device (110) according to any one of the preceding claims, wherein the electrically driven driving unit (136) for the air flow regulating element (124) is further configured for bringing the air flow regulating element (124) from the at least one open position in the closed position after expiry of an opening time of the air flow regulating element (124).
The device (110) according to the preceding claim,
- wherein the opening time is a variable opening time, wherein the device (110) comprises a further user input unit, wherein the further user input unit is configured to receive the variable opening time of the air flow regulating element (124) and cause the electrically driven driving unit (136) to bring the air flow regulating element (124) from the at least one open position in the closed position after expiry of the received variable opening time;

- wherein the opening time is a predetermined opening time.
The device (110) according to any one of the preceding claims, wherein the device (146) further comprises at least one detection device (146), wherein the detection device (146) is configured for detecting at least one of: a position; a velocity of the piston (114) at least partially while the piston (114) is moved to force the fastener into the workpiece, wherein the device (110) further comprises a control unit for controlling the electrically driven driving unit (136) based on at least one of: the position of the piston (114); the velocity of the piston (114).
The device (110) according to any one of the preceding claims, wherein the electrically driven driving unit (136) is further configured for keeping the air flow regulating element (124) in the at least one open position.
The device (110) according to any one of the preceding claims 1 to 9, wherein the device (110) comprises a position holding device (178) configured to keep the air flow regulating element (124) in the at least one open position.
The device (110) according to the preceding claim, wherein the position holding device (178) comprises an electromagnet, wherein the electromagnet is configured to keep the air flow regulating element (124) in the at least one open position when activated, wherein the position holding device (178) comprises a magnetic element or a permamagnet, wherein the magnetic element or the permamagnet is configured to be attracted by the activated electromagnet.
The device (110) according to any one of the preceding claims, wherein the electrically driven driving unit (136) for the air flow regulating element (124) is arranged within the pressurized volume.
The device (110) according to any one of the preceding claims, wherein the device (110) comprises a preload driving unit (156), wherein the preload driving unit (156) is configured for preloading the device (110) by forcing the piston (114) in a ready position into which the piston (114) is moved in a manner that the pressurized volume, specifically a volume of the second chamber compartment (128), is decreased, wherein the preload driving unit (156) is used as the electrically driven driving unit (136) for the air flow regulating element (124), wherein the device (110) comprises a contact piece (162), wherein the contact piece (162) is configured to bring the air flow regulating element (124) from the closed position in the at least one at least one open position when the preloading of the device (110) is released.
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.