Fastener driving tool

Patent metadata

Field	Value
Publication number	US-11738429-B2
Application number	US-201917056718-A
Country	US
Kind code	B2
Filing date	May 29, 2019
Priority date	Jun 6, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A tool comprising a drive-in element, transferring a fastening element into a substrate along setting axis by a setting energy E kin , a drive for driving the drive-in element along the setting axis, the drive comprising a capacitor, a rotor, and a coil, wherein current flows through the coil generating a magnetic field accelerating the drive-in element toward the fastening element, wherein a current intensity A coil of current flowing through the excitation coil while discharging the capacitor has a time profile with a rising edge, a maximum current intensity A max and a falling edge, A coil rising during current rise time Δt rise from 0.1 to 0.8 times A max and during impact time Δt impact is more than 0.5 times the A max , wherein Δt rise is at least 0.020 ms and at most 0.275 ms and/or the impact time Δt impact is at least 0.15 ms and at most 2.0 ms.

First claim

The invention claimed is:

1. A setting tool for driving fastening elements into a substrate, comprising a holder for holding a fastening element; a drive in element for transferring a fastening element held in the holder into the substrate along a setting axis by a setting energy E kin ; and, a drive for driving the drive-in element toward the fastening element along the setting axis, wherein the drive comprises an electrical capacitor, a squirrel-cage rotor arranged on the drive-in element, and an excitation coil; wherein current flows through the excitation coil during discharge of the electrical capacitor and generates a magnetic field that accelerates the drive-in element toward the fastening element, wherein a current intensity A coil of the current flowing through the excitation coil during the discharge of the electrical capacitor has a time profile with a rising edge, a maximum current intensity A max and a falling edge, wherein the current intensity A coil rises during a current rise time Δt rise from 0.1 times to 0.8 times the maximum current intensity A max and during an impact time Δt impact is more than 0.5 times the maximum current intensity A max but not greater than the maximum current intensity A max , and wherein the current rise time Δt rise is at least 0.020 ms and at most 0.275 ms and/or the impact time Δt impact is at least 0.15 ms and at most 2.0 ms.

2. The setting tool as claimed in claim 1 , wherein the current rise time Δt rise is at least 0.05 ms and at most 0.2 ms and/or the impact time Δt impact is at least 0.2 ms and at most 1.6 ms.

3. The setting tool as claimed in claim 1 , wherein a maximum current density in the excitation coil during the discharge of the electrical capacitor is at least 800 A/mm 2 and at most 3200 A/mm 2 .

4. The setting tool as claimed in claim 1 , wherein the electrical capacitor and the excitation coil are arranged in an electrical oscillating circuit, and wherein the electrical capacitor has a capacitance C cap and an electrical capacitor resistance R cap , the excitation coil has a self-inductance L coil and a coil resistance R coil and the electrical oscillating circuit has a total resistance R total .

5. The setting tool as claimed in claim 4 , wherein a ratio of the electrical capacitor resistance R cap to the total resistance R total is at most 0.6.

6. The setting tool as claimed in claim 4 , wherein a ratio of the self-inductance L coil to the coil resistance R coil is at least 800 μH/Ω and at most 4800 μH/Ω.

7. The setting tool as claimed in claim 4 , wherein the electrical capacitor has an electrical capacitor time constant τ cap =C cap R cap and the excitation coil has a coil time constant τ coil =L coil /R coil , and wherein a ratio of the coil time constant τ coil to the electrical capacitor time constant τ cap is at least 10.

8. The setting tool as claimed in claim 1 , wherein the drive-in element is provided for transferring a fastening element held in the holder into the substrate with a setting energy E kin of at least 30 J and at most 600 J, wherein the drive-in element has a piston diameter d K and a piston mass m K and wherein, for the piston diameter d K

2
3

⁢

(

a
+

b
⁢

E

k
⁢
i
⁢
n

n

)

≤

d
K

≤

4
3

⁢

(

a
+

b
⁢

E
kin
n

)

where a=33 mm, b=6 mmJ −n and n=⅓ and/or, for the piston mass m K ,

2
3

⁢

(

c
+

d
⁢

E

k
⁢
i
⁢
n

n

)

≤

m
K

≤

5
3

⁢

(

c
+

d
⁢

E
kin
n

)

where c=20 g, d=30 gJ −n and n=⅓.

9. The setting tool of claim 1 , comprising a hand-held setting tool.

10. The setting tool of claim 5 , wherein the ratio of R cap to R total is at most 0.5.

11. The setting tool as claimed in claim 5 , wherein a ratio of the self-inductance L coil to the coil resistance R coil is at least 800 μH/Ω and at most 4800 μH/Ω.

12. The setting tool as claimed in claim 5 , wherein the electrical capacitor has an electrical capacitor time constant τ cap =C cap R cap and the excitation coil has a coil time constant τ coil =L coil /R coil , and wherein a ratio of the coil time constant τ coil to the electrical capacitor time constant τ cap is at least 10.

13. The setting tool as claimed in claim 6 , wherein the electrical capacitor has an electrical capacitor time constant τ cap =C cap R cap and the excitation coil has a coil time constant τ coil =L coil /R coil , and wherein a ratio of the coil time constant τ coil to the electrical capacitor time constant τ cap is at least 10.

14. The setting tool as claimed in claim 2 , wherein a maximum current density in the excitation coil during the discharge of the electrical capacitor is at least 800 A/mm 2 and at most 3200 A/mm 2 .

15. The setting tool as claimed in claim 2 , wherein the electrical capacitor and the excitation coil are arranged in an electrical oscillating circuit, and wherein the electrical capacitor has a capacitance C cap and an electrical capacitor resistance R cap , the excitation coil has a self-inductance L

Assignees

• Hilti Ag

Inventors

• Dittrich Tilo
• Bruggmueller Peter
• Abu Antoun Chafic

Classifications

• H02K17/168

  having single-cage rotors · CPC title

• B25C1/06 Primary

  operated by electric power · CPC title

• H02K17/165

  Electricity · mapped topic

• H02K41/02

  Linear motors; Sectional motors · CPC title

• H02K7/145

  Hand-held machine tool · CPC title