PULSE DRIVE CIRCUIT FOR COILS OF DENTAL IMPACT TOOLS AND THE LIKE

• US 3,673,475 A
• Filed: 09/15/1970
• Issued: 06/27/1972
• Est. Priority Date: 09/15/1970
• Status: Expired due to Term

• Current Assignee: Ralph H. Britton Jr
• Original Assignee: Ralph H. Britton Jr
• Inventors: Britton, Ralph H. Jr.
• Primary Examiner(s): Myers, Lewis H.
• Assistant Examiner(s): Witkowski, Stanley J.
• Application Number:
  US05/072,277
• Time in Patent Office: 651 Days
• Field of Search: 318/114,116,118,122-134 128/24A,421,303 32/53
• US Class Current: 318/122
• CPC Class Codes: H02K 33/12 with armatures moving in alternate directions by alternate energisation of two coil systems

Abstract

A drive circuit for dental percussion tools or hammers and the like including a power supply coupled with a timing circuit which provides suitable output pulses of selectable frequency. The output of the timing circuit is connected to a recoil-drive pulse forming circuit which includes one shot multivibrators one of which generates recoil pulses and the other of which generates drive pulses immediately following the recoil pulses. These pulses are amplified and applied to the solenoid of the dental hammer unit to alternately energize coils of the solenoid to cause the armature to reciprocate rapidly and impart repetitive impacts to a tool element. The circuit includes means for enabling adjustment of pulse frequency, pulse width and pulse amplitude.

Claims

1. A drive circuit for a percussion tool employing coil means to which pulses are supplied to cause an armature to reciprocate and impact a tool element comprising power source means, a timing circuit for providing an output pulse train, said timing circuit being coupled to said power source means and having means for adjusting the frequency of said pulse train independent of the frequency of said power source means, pulse forming circuit means coupled with said timing circuit for generating a series of pulses in response to the signal train from said timIng circuit, said series of pulses comprising repetitively occurring first and second pulses with said second pulses immediately following respective first pulses, said pulse forming circuit means including means for adjusting the width of said first and second pulses, and output circuit means coupled with the said pulse forming circuit means for applying said series of pulses to said percussion tool, said output circuit means including means for adjusting the amplitude of said first and second pulses.

2. A drive circuit as in claim 1 wherein said pulse forming circuit means comprises a pair of multivibrators, the first of which is triggered by said pulse train for generating said first pulses of said series of pulses, and the second of which is triggered in response to said first pulses of said series for generating said second pulses of said series.

3. A drive circuit as in claim 1 wherein said output circuit means includes a pair of amplifiers for respectively receiving said first and second pulses of said series of pulses, and includes means (a) for independently adjusting and (b) for simultaneously adjusting the amplitude of said first and second pulses before said pulses are applied to said percussion tool.

4. A drive circuit for a percussion tool employing coil means to which pulses are supplied to cause an armature to reciprocate and rapidly impart impacts to a tool element comprising power supply means, a timing circuit for providing an output signal train, said timing circuit being coupled with said power supply means and having means for adjusting the frequency of said signal train independent of the frequency of said power supply means, pulse forming circuit means coupled with said timing circuit for generating a series of pulses in response to the signal train from said timing circuit, said series of pulses comprising repetitively occurring first and second pulses with said second pulses following respective first pulses, said pulse forming circuit means including means for selectively adjusting the respective widths of said first and second pulses, and output circuit means coupled with said pulse forming circuit means for applying said series of pulses to said percussion tool, and said output circuit means including means for adjusting the amplitude of said first and second pulses.

5. A drive circuit for a percussion tool employing coil means to which pulses are supplied to cause an armature to reciprocate and impact a tool element comprising a timing circuit for providing an output pulse train, said timing circuit having means for adjusting the frequency of said pulse train, pulse forming circuit means coupled with said timing circuit for generating a series of pulses in response to said pulse train from said timing circuit, said series of pulses comprising repetitively occurring first and second pulses with said second pulses immediately following respective first pulses, said pulse forming circuit means including first and second multivibrators for respectively providing said first and second pulses of said series of pulses, said first multivibrator being triggered by the pulse train from said timing circuit and the second multivibrator being triggered by said first pulses of the series of pulses generated by said first multivibrator, and output circuit means coupled with said pulse forming circuit means for applying said series of pulses to said percussion tool, said output circuit means comprising a pair of amplifiers for independently amplifying said respective first and second pulses of said series of pulses, and including means for applying the amplified first and second pulses to respective portions of said coil means of said percussion tool.

6. A drive circuit for a percussion tool employing coil means to which pulses are supplied to cause an armature to reciprocate and rapidly impart impacts to a tool element comprising a timing circuit for providing an output signal trAin, said timing circuit having means for adjusting the frequency of said signal train, pulse forming circuit means coupled with said timing circuit for generating a series of pulses in response to the signal train from said timing circuit, said series of pulses comprising repetitively occurring first and second pulses with said second pulses following respective first pulses, said pulse forming circuit means comprising a pair of multivibrators, the first of which is triggered by said signal train for generating said first pulses of said series of pulses, and the second of which is triggered in response to said first pulses of said series for generating said second pulses of said series, and said pulse forming circuit means including means for adjusting the width of said first and second pulses, and output circuit means coupled with said pulse forming circuit means for applying said series of pulses to said percussion tool, and said output circuit means including means for adjusting the amplitude of said first and second pulses.

7. A drive circuit as in claim 6 wherein each of said multivibrators includes means for independently adjusting the pulse width of said first and second pulses of said series of pulses.

8. A drive circuit as in claim 7 wherein said output circuit means includes a pair of amplifiers for respectively receiving said first and second pulses of said series of pulses, and includes means for independently adjusting the amplitude of said first and second pulses before said pulses are applied to said percussion tool.

9. A drive circuit for a percussion tool employing coil means to which pulses are supplied to cause an armature to reciprocate and rapidly impart impacts to a tool element comprising a timing circuit for providing an output signal train, said timing circuit having means for adjusting the frequency of said signal train, pulse forming circuit means coupled with said timing circuit for generating a series of pulses in response to the signal train from said timing circuit, said series of pulses comprising repetitively occurring first and second pulses with said second pulses following respective first pulses, said pulse forming circuit means including first and second multivibrators for respectively providing said first and second pulses of said series of pulses, said first multivibrator being triggered by the signal train from said timing circuit and the second multivibrator being triggered by said first pulses of the series of pulses generated by said first multivibrator, and said pulse forming circuit means including means for adjusting the width of said first and second pulses, and output circuit means coupled with said pulse forming circuit means for applying said series of pulses to said percussion tool, said output circuit means comprising a pair of amplifiers for independently amplifying said respective first and second pulses of said series of pulses, and said output circuit means including means for adjusting the amplitude of said first and second pulses and means for applying the amplified first and second pulses to respective portions of said coil means of said percussion tool.

10. A drive circuit for a percussion tool employing recoil and drive coils to which recoil and drive impulses are supplied to cause an armature to reciprocate and impact a tool element, comprising power source means, timing circuit means for providing an output pulse train, said timing circuit means being coupled to said power source means and having means for adjusting the frequency of said pulse train independent of the frequency of said power source means, pulse forming circuit means coupled with said timing circuit means for generating a series of pulses in response to said pulse train from said timing circuit means, said pulse forming circuit means including first and second stages with the first of said stages being responsive to said timing circuit means for generating recoil pulses and the second of said stages being responsive to the first of said stages for generating drive pulses, with the drive pulses immediately following respective recoil pulses, said pulse forming circuit means including means for adjusting the pulse width of said recoil and drive pulses, and output circuit means coupled with said pulse forming circuit means for applying said recoil and drive pulses respectively to the recoil and drive coils of said percussion tool, said output circuit means including amplifier means and means for independently adjusting the amplitude of said recoil pulses and said drive pulses before application thereof to said coils.