Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS3924692 A
Publication typeGrant
Publication dateDec 9, 1975
Filing dateFeb 6, 1974
Priority dateFeb 6, 1974
Also published asCA1017902A, CA1017902A1, DE2501539A1
Publication numberUS 3924692 A, US 3924692A, US-A-3924692, US3924692 A, US3924692A
InventorsSaari Oliver Edward
Original AssigneeIllinois Tool Works
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fastener driving tool
US 3924692 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Dec. 9, 1975 United States Patent [1 Saari l h msq ac fnw wh Moe ed JDDSGB 00 2244 677777 999999 l l l l ll 360004 [22] Filed: 1974 FOREIGN PATENTS OR APPLICATIONS 271,819 3/1914 Germany 173/119 21 App]. No.: 440,224

52 US. 173/117; 173/119; 173/123; Primary EmmineHFra'nk Abbott 17 9 Assistant ExaminerWI1liam F. Pate, Ill B25C 1/06 l73/15,16,13,119,117,

Attorney, Agent, or FirmT. W. Buckman; R. W. Beart [51] Int. [58] Field of Search.........

[57] ABSTRACT A driving tool utilizing an electric motor to periodi- [56] References Cited UNITED STATES PATENTS cally compress a spring and utilize the energy stored in the spring as the force provided for an impact stroke Parrish.......................

Miller Mi'iller Scwarzkopf..... Shinn.............. Moorhead. ..........m...

E e W US. Patent Dec. 9, 1975 Sheet 1 0f 2 3,924,692

\ \Qlhk U.S. Patent Dec. 9, 1975 Sheet 2 f2 3,924,692

"ilill mun FASTENER DRIVING TOOL BACKGROUND OF THE INVENTION Tools for driving fasteners, such as nails, staples or the like, have been proposed which operate principally on a pneumatic power source or cartridge activated power source. Pneumatic devices are commonly used because such a device provides a lightweight, simple tool which delivers energy sufficient to drive fasteners. However, such a tool requires convenient sources of air pressure, such as compressors and air hoses. The use of such a tool on a construction site, for example, would be impractical.

Cartridge activated devices provide a high energy source for a single shot tool but suffer from certain dis= advantages centering on the noise and cartridge disposal problems.

In addition to these prior art methods, electric operated tools have been utilized in which a solenoid directly drives a ram which in turn drives a fastener. This type of tool requires extremely high current to operate a low power tool.

SUMMARY OF THE INVENTION The driving tool of the subject invention allows electric power to be fed into the too] more or less continuously and allows such energy to be stored in a spring means. The spring provides the actual driving force to seat a fastener when the spring is suddenly allowed to release.

The spring is periodically compressed and released through the use of coacting helicoidal cam elements one of which elements is rotated about the axis of the ram and adapted to allow the ram to pass through upon the release of the stored energy. A second cam member is fixedly attached to the ram and restrained from rotary motion so that the rotation of the first helicoidal cam causes the ram to be forced in an axial direction compressing a spring until the mating cam configuration allows the ram to be driven rapidly under the stored energy of the spring through the rotatable cam.

Other aspects of the invention include the provision of a cushion to prevent the driving and driven cams from directly receiving the high shock loads as the ram BRIEF DESCRIPTION OF. THE DRAWINGS FIG. 1 is a side elevational view in partial section of a tool forming one embodiment of'the present invention.

of FIG. 1 showing the tool as the spring means is compressed.

FIG. 2 is a partial side elevational view similar to that FIG. 3 is a sectional view taken substantially along lines 33 of FIG. 1.

FIG. 4 is a sectional view taken along the lines 4-4 of FIG. 1.

FIG. 5 is an enlarged elevational view in partial section of the pair of coacting helicoidal cams used in the present invention.

FIG. 6 is a graphical representation of the configuration of the cam surface in an alternate embodiment of the cam devices.

FIGS. 7-9 are various schematic representations of the switching mechanisms showing the various conditions capable as a result of the limit switch.

FIG. 10 is a partial side elevational view of another embodiment of the present invention showing an alternate spring mechanism.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings and particularly to FIG. I, the fastener driving tool 10 will be seen to include an electric motor casing 12 and an actuator housing 14. Mounted axially within the housing are a pair of mating helicoidal cams 16 and 18. The cam 16 will include a radially extending flange 36 above the cam surfaces and a guide shaft 30 extending coaxially of the cam above the flange. Extending in the opposite axial direction through the cam surfaces is an elongate ram portion 40 adapted to drive sequentially fed fasteners in a manner which will be described in detail later herein. The lower cam portion 18 will be of a substantially identical helicoidal shape and positioned to mate with the helicoidal surfaces of the upper cam 16. Cam 18 will also include an integral ring gear 20 surrounding the axis of the cam. A bore 26 is formed through the axis of the cam and adapted to receive the driving ram 40. Attention is directed to FIG. 5 for the details of the coacting cam 16 and 18.

The upper cam 16 is continuously biased downwardly to the position shown in FIG. 1. The coil spring 38 is interposed between the upper portions of the housing and the flange 36 for this biasing purpose.

Reference is again made to FIG. 5 as well as FIGS. 1 and 2 for a general description of the operation of the tool.Each cam element 16 and 18 will include a generally helical surface extending approximately 360 about the central axis of the element with the upper and lower extremities of the helical surface being connected by sharp drop-off portions 17 and 19, respectively. The drop-off portions will extend parallel to the central axis of the cams and thus to the axis of the driving ram 40. As lower cam 18 is rotated, and upper cam 16 restrained from rotation, the helical mating surfaces on the cams will operate to force the upper cam 16 rearwardly of the housing compressing the spring 38. The latter stage of this compression and relative positions at thecams is shown clearly in FIG. 2. Further rotation of the lower cam from that shown in FIG. 2 will allow the drop-off portions 17 and 19 to become coplanar and at that instant the ram and upper cam will be driven forcefully downwardly under the bias of the compressed spring 38. Since the ram 40 extends through a bore in the lower cam 18, it will contact a fastener member 72 fed beneath the striker 42 on the extremity of the ram.

.Since an important aspect in the operation of the tool is the restraint from rotation of upper cam 16, the guide shaft 30 may be provided with flats, such as 32, for mating telescopic association with a complementary bore 34 in guide sleeve 28. Attention is directed to FIGS. 1

3 and 4 for this relationship. The interaction of the guide shaft 30 and guide sleeve 28 will allow the forces acting on the upper cam to be essentially along the center line of the ram and eliminate any possiblity of cocking as the spring is compressed or released.

The source of power to compress the spring in the housing may conveniently be provided by a conventional electric motor within the casing 12. The output shaft 24 of the motor is connected to a pinion 22 through a gear set 25. Upon actuation of the motor, rotary power will be imparted to the lower cam 18 through the interaction of the pinion 22 and the ring gear 20, which is integrally connected to the cam. Cam portion 18 will also include a sleeve portion extending axially forwardly for reception in a cavity at the forward end of the housing 14. Suitable bearings 23 are interposed between this sleeve and the housing to permit free rotation thereof.

Actuation of the electric motor 12 is initiated through a trigger 58 which in turn operates a switch 56. One of the features of the invention is a switching arrangement which allows the ram 40 to be retained in a cocked position for essentially instantaneous driving upon the actuation of the trigger 58 by the operator. For this purpose, attention is directed to FIGS. 1 and A pivot arm lever 50 is mounted adjacent the rear of the housing 14 with a terminal contact portion 52 aligned axially with the guide shaft 30. The extremity of the pivot arm 50 opposite the contact point 52 is adapted to contact a switch 54 which is normally closed.

FIG. 7 represents the switch configuration during the., portion of the compression cycle immediately following impact stroke after the actuation of the electric motor by the trigger 58 and switch 56. The instantaneous position of the elements can be represented by the condition shown in FIG. 1.

As the driving ram and associated camming surface reapproach the condition of maximum compression of the spring rearwardly in the housing, the upper extremity of the guide shaft 30 will open limit switch 54 through the interaction of the pivot arm 50. This switching condition is represented by FIG. 8 in which .the circuit is now completely open and electric motor thus de-energized. The relative positions of the cams in this position can be represented by that shown in FIG.

"2. The switching condition of FIG. 8 and the cam position of FIG. 2 now present a tool which is cocked under the compression of the spring for essentially instantaneous driving upon direction of the operator through trigger 58.

FIG. 9 shows switch 56 closed upon the actuation of trigger 58 and indicates an instantaneous condition of the circuit after the trigger has started the motor to slightly rotate the lower cam 20 from the position shown in FIG. 2 until the drop-off portions of the cam are aligned. The immediate switch condition following the condition shown in FIG. 9 would be that shown in FIG. 7 assuming the operator releases the trigger. It should be understood that the operator can affect continuous operation of the device by continued activation of the trigger device 58.

The impact shock of the driving ram is prevented from being absorbed by the camming surfaces themselves by a resilient annular ring cushion 44-positioned beneath the flange 36 and a shoulder 46 mounted in the housing.

FIG. 10 shows an alternate embodiment of the power driving tool which utilizes a compressible gas, such as air or the like, as the spring means. The rearmost extremity of the housing 14a provides the chamber for such a compressible gas. A cup-like piston is fixedly mounted to the upper cam 16a. The gas chamber is sealed by suitable seal means 84 between the inner walls of the housing 14a and the outer side walls of the piston 80. The piston may be fixedly retained to the cam and guide shaft 30a by threaded fastener means, such as 81 and 82. A valve 86 is provided for selectively charging the chamber with the appropriate compressible gas. This embodiment will thus allow the compressibility of the spring to be conveniently varied. The upper cam portion may be restrained from rotation through mating key and slot devices 86 and 88.

While the camming surfaces have been shown as true helices, it may be advisable in certain conditions to provide a helical surface which has a variable rise from the starting point of the helical path to the termination point on the helical surface at the top of the cam. FIG. 6 shows, in a graphical form, how such a cam may be provided with a somewhat flattened surface 90 at the upper extremities of the cam and a conventional rising portion 92 at the beginning portions of the cam. Such a cam structure will enable the torque required to compress the spring to be essentially constant as the upper cam 16 reaches the point of maximum compression of the spring. This will enable the power requirement from the electric motor to remain substantially constant during all stages of compression and will keep the maximum amperage required of the tool to a minimum.

Thus, it is apparent that there has been provided, in accordance with the invention, a power driving tool which operates with electric power that satisfied the advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.

I claim:

1. In a fastener driving tool, a housing, driving means mounted for axial reciprocating movement therein, the driving means including an elongate ram, guide shaft and a cup-shaped piston opening rearwardly of the housing and the ram including a base portion extending radially outwardly of both the guide shaft and the ram and further including upstanding wall portions extending longitudinally of the housing from the base portion, said piston being located between the ram and guide shaft, seal means positioned between the upstanding wall portion of the piston and the associated inner periphery of the housing, a first helicoidal cam means fixedly attached to the driving means so that the ram extends coaxially through the cam means, a rotatable means for actuating the driving means including a second helicoidal cam means fixedly attached to a gear for rotation about the axis of the ram, a bore extending through the actuating means and second helicoidal cam to allow the ram to pass therethrough and create an impact force on a fastener positioned beneath the cams, compressible spring means in the housing to urge the driving means forwardly in the housing toward the second cam means, the spring means comprising a chamber at the rearmost extremity of the housing, a predetermined volume of gas stored in the chamber, valve means in the chamber to selectively vary the bias of the gas spring means on the cup-shaped piston, a sleeve mounted in the chamber and extending forwardly therein, coaxial with the guide shaft to receive the guide shaft during the reciprocation of the driving means in the housing, the housing also including shoulder means to support the cup-shaped piston when the driving means is in its forward position in the housing, resilient cushion means positioned between the piston and the shoulder means to absorb the impact shock of the driving means and thus prevent abutting cam sur faces to impact each other, a drive shaft driven by a source of rotary power located adjacent the housing, gear means operatively connecting the drive shaft to the gear attached to the second helicoidal cam means to transmit rotary motion to the actuating means, the helicoidal cams including sharp drop-off portions which allow the spring means to periodically drive the ram forwardly to drive a fastener.

2. The driving tool in accordance with claim 1, wherein each helicoidal cam means includes a helical surface extending approximately 360 about the axis of the ram, the sharp drop-off portion of each cam means comprising a surface extending generally parallel to the axis of the ram whereby the tool will provide one driving stroke per revolution of the second helicoidal cam.

3. The driving tool in accordance with claim 1, wherein the helicoidal cam means include helical-like surfaces wherein the slope of these surfaces decreases adjacent the drop-off portions of the cam so that the axial displacement of the driving means decreases as the spring approaches its maximum compression.

4. The driving too] in accordance with claim 1, wherein the source of rotary power comprises an electric motor.

5. The driving tool in accordance with claim 4, wherein switch means are interposed between the driving means and the source of rotary power to cock the driving means in a position adjacent the rearwardmost position of the driving means when the spring means is near its maximum compression.

6. The driving tool in accordance with claim 5, wherein the switch means comprises a pair of switches. a first switch being actuated by means to open the electric circuit and stop the motor as the guide shaft approaches its rearwardmost position in the housing, a second switch operative to close the electric circuit and allow the ram to be driven from a cocked position.

7. A driving tool in accordance with claim 1, wherein the internal surfaces of the sleeve and the guide shaft form telescoping noncircular cross-sectional configurations to prevent the driving means from rotating about its axis as the actuating means forces it rearwardly against the bias of the compressible spring means.

8. A driving too] in accordance with claim 1, wherein the driving means and housing include cooperating keys and slots to prevent the driving means from rotating as the actuating means forces the driving means rearwardly against the bias of the compressible spring means.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1497635 *Sep 24, 1923Jun 10, 1924Hayes Parrish FairfaxAir hammer
US1634623 *Feb 10, 1925Jul 5, 1927Miller Smythe Electric CompanyPower hammer
US1708451 *Aug 8, 1925Apr 9, 1929Firm Elektro Hammer A GPercussive tool
US2408484 *Nov 6, 1943Oct 1, 1946Wodack Electric Tool CorpPercussive tool
US2484471 *Dec 26, 1947Oct 11, 1949Charles A ShinnHammer drill
US3006202 *Mar 17, 1958Oct 31, 1961Samuel J ForbesRotary and percussive tool
US3371725 *Mar 1, 1966Mar 5, 1968Hendrik HoffmannElectric hammer drill attachment
US3583498 *Feb 13, 1970Jun 8, 1971Ceg CorpImpact hammer
US3687008 *Feb 1, 1971Aug 29, 1972W J Savage Co IncPressure fluid controlled reciprocating mechanism
US3695365 *Nov 6, 1970Oct 3, 1972Bosch Gmbh RobertTorque and impulse transmitting machine
US3804180 *Jul 7, 1972Apr 16, 1974Antipov GImpact wrench
US3845826 *Feb 23, 1973Nov 5, 1974Skil CorpRotary disconnect for a rotary hammer tool
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4103747 *Jan 14, 1977Aug 1, 1978Finney James LBuffer spring for an impact tool
US4171024 *Dec 29, 1977Oct 16, 1979Wilson Roger APower hammer
US4214944 *May 23, 1978Jul 29, 1980American Can CompanyAdhesive bonding of assembly parts
US4215808 *Dec 22, 1978Aug 5, 1980Sollberger Roger WPortable electric fastener driving apparatus
US4431062 *May 4, 1979Feb 14, 1984Robert Bosch GmbhRotating drive for impact hammer
US4572053 *Feb 27, 1984Feb 25, 1986Teleflex IncorporatedOrdnance ejector system
US4625903 *Jul 3, 1984Dec 2, 1986SencorpMultiple impact fastener driving tool
US5794325 *Jun 7, 1996Aug 18, 1998Harris CorporationElectrically operated, spring-biased cam-configured release mechanism for wire cutting and seating tool
US7537146 *Jul 7, 2006May 26, 2009Hilti AktiengesllschaftHand-held drive-in power tool
US7717191Nov 21, 2007May 18, 2010Black & Decker Inc.Multi-mode hammer drill with shift lock
US7717192Nov 21, 2007May 18, 2010Black & Decker Inc.Multi-mode drill with mode collar
US7735575Nov 21, 2007Jun 15, 2010Black & Decker Inc.Hammer drill with hard hammer support structure
US7757922 *Feb 4, 2008Jul 20, 2010Jelley Technology Co., LtdPower beating device
US7762349Nov 21, 2007Jul 27, 2010Black & Decker Inc.Multi-speed drill and transmission with low gear only clutch
US7770660Nov 21, 2007Aug 10, 2010Black & Decker Inc.Mid-handle drill construction and assembly process
US7789282 *Aug 1, 2008Sep 7, 2010Chervon LimitedNailer device
US7798245Nov 21, 2007Sep 21, 2010Black & Decker Inc.Multi-mode drill with an electronic switching arrangement
US7832610 *Mar 26, 2008Nov 16, 2010Hitachi Koki Co., Ltd.Fastener driving tool having impact buffering mechanism
US7854274Nov 21, 2007Dec 21, 2010Black & Decker Inc.Multi-mode drill and transmission sub-assembly including a gear case cover supporting biasing
US7922059 *Mar 27, 2007Apr 12, 2011Hilti AktiengesellschaftHand-held drive-in power tool
US7938305May 31, 2007May 10, 2011Stanley Fastening Systems, L.P.Fastener driving device
US7963430 *Sep 23, 2009Jun 21, 2011Chervon LimitedNailer device
US7987920Apr 26, 2010Aug 2, 2011Black & Decker Inc.Multi-mode drill with mode collar
US7992756 *Sep 28, 2009Aug 9, 2011Hilti AktiengesellschaftHand-held fastener driver
US8109343Jun 29, 2011Feb 7, 2012Black & Decker Inc.Multi-mode drill with mode collar
US8256527Feb 4, 2010Sep 4, 2012Chervon LimitedAuto hammer
US8292001Aug 16, 2010Oct 23, 2012Black & Decker Inc.Multi-mode drill with an electronic switching arrangement
US8297373Feb 17, 2011Oct 30, 2012Milwaukee Electric Tool CorporationImpact device
US8308039Feb 4, 2010Nov 13, 2012Chervon LimitedClamping mechanism for an auto hammer
US8348119 *Nov 19, 2009Jan 8, 2013Chervon (Hk) LimitedNailer device
US8348120Feb 4, 2010Jan 8, 2013Chervon LimitedAuto hammer
US8424734Feb 4, 2010Apr 23, 2013Chervon LimitedClamping mechanism for an auto hammer
US8439243 *Nov 19, 2009May 14, 2013Chervon LimitedNailer device
US8505798Feb 23, 2009Aug 13, 2013Stanley Fastening Systems, L.P.Fastener driving device
US8555998Dec 29, 2011Oct 15, 2013Black & Decker Inc.Multi-mode drill with mode collar
US8783378Nov 3, 2010Jul 22, 2014Chervon LimitedAuto hammer
US8807413 *Jun 13, 2011Aug 19, 2014Hilti AktiengesellschaftDriving device
US8844787 *Jan 13, 2009Sep 30, 2014Hitachi Koki Co., Ltd.Fastener driving tool
US8857692 *Jan 13, 2009Oct 14, 2014Hitachi Koki Co., Ltd.Fastener driving tool
US9205546Jun 13, 2011Dec 8, 2015Hilti AktiengesellschaftDriving device
US9463561 *May 17, 2012Oct 11, 2016Hilti AktiengesellschaftFastener driving tool
US9527197 *Jun 13, 2011Dec 27, 2016Hilti AktiengesellschaftDriving device
US9643306Apr 15, 2014May 9, 2017Illinois Tool Works Inc.Fastener-driving tool including a driving device
US9701001Apr 30, 2014Jul 11, 2017Arrow Fastener Co., LlcMotor-driven fastening tool
US20050194420 *Mar 2, 2005Sep 8, 2005Mario ZahnerElectromagnetically driven setting tool and method of driving same
US20070023472 *Jul 7, 2006Feb 1, 2007Hilti AktiengesellschaftHand-held drive-in power tool
US20070228101 *Mar 27, 2007Oct 4, 2007Ulrich SchiestlHand-held drive-in power tool
US20080017689 *May 31, 2007Jan 24, 2008David SimonelliFastener driving device
US20080041914 *May 31, 2007Feb 21, 2008David SimonelliFastener driving device
US20080048000 *May 31, 2007Feb 28, 2008David SimonelliFastener driving device
US20080237294 *Mar 26, 2008Oct 2, 2008Hitachi Koki Co. Ltd.Fastener driving tool having impact buffering mechanism
US20090045241 *Aug 1, 2008Feb 19, 2009Chervon LimitedNailer device
US20090179062 *Jan 13, 2009Jul 16, 2009Hitachi Koki Co., Ltd.Fastener driving tool
US20090188766 *Jan 13, 2009Jul 30, 2009Hitachi Koki Co., Ltd.Fastener driving tool
US20090194576 *Feb 4, 2008Aug 6, 2009Feng-Ho WangPower beating device
US20100089963 *Sep 28, 2009Apr 15, 2010Hilti AktiengesellschaftHand-held fastener driver
US20100089965 *Sep 23, 2009Apr 15, 2010Chervon LimitedNailer device
US20100089967 *Nov 19, 2009Apr 15, 2010Chervon Limited.Nailer device
US20100089968 *Nov 19, 2009Apr 15, 2010Chevon LimitedNailer device
US20100116864 *Nov 4, 2009May 13, 2010Pneutools, IncorporatedMotorized fastener applicator
US20100147919 *Dec 10, 2009Jun 17, 2010Hilti AktiengesellschaftHand-held drive-in tool
US20110011912 *Feb 4, 2010Jan 20, 2011Chervon LimitedAuto hammer
US20110094763 *Feb 4, 2010Apr 28, 2011Chervon LimitedAuto hammer
US20110100660 *Feb 4, 2010May 5, 2011Chevron LimitedAuto hammer
US20110108298 *Nov 3, 2010May 12, 2011Chervon LimitedAuto hammer
US20110114696 *Feb 4, 2010May 19, 2011Chevron LimitedAuto hammer
US20110121048 *Feb 4, 2010May 26, 2011Chervon LimitedAuto hammer
US20110203824 *Feb 17, 2011Aug 25, 2011Elger William AImpact device
US20110233257 *Jun 10, 2011Sep 29, 2011Chervon (Hk) LimitedNailer device
US20110303726 *Jun 13, 2011Dec 15, 2011Hilti AktiengesellschaftDriving device
US20110303731 *Jun 13, 2011Dec 15, 2011Hilti AktiengesellschaftDriving device
US20120153001 *Dec 14, 2011Jun 21, 2012Hilti AktiengesellschaftElectrically powered bolt setting device
US20120292064 *May 17, 2012Nov 22, 2012Hilti AktiengesellschaftFastener driving tool
US20160368127 *Sep 2, 2016Dec 22, 2016Hilti AktiengesellschaftFastener driving tool
USRE44344 *May 17, 2012Jul 9, 2013Chervon (Hk) LimitedNailer device
USRE44602 *May 17, 2012Nov 19, 2013Chervon (Hk) LimitedNailer device
CN1895854BJul 11, 2006Sep 21, 2011希尔蒂股份公司Hand-held drive-in power tool
CN101456177BDec 9, 2008Aug 8, 2012喜利得股份公司Hand-held fastener driving device
DE102008054816A1Dec 17, 2008Jul 1, 2010Hilti AktiengesellschaftHandgeführtes Eintreibgerät
EP2199027A1Nov 23, 2009Jun 23, 2010HILTI AktiengesellschaftManually operated fastening device
EP2944427A3 *Apr 29, 2015Feb 24, 2016Arrow Fastener Company, LLCMotor-driven fastening tool
WO2007142997A3 *May 31, 2007Aug 21, 2008Stanley Fastening Sys LpFastener driving device
U.S. Classification173/117, 173/203
International ClassificationB25C1/00, B25C1/06
Cooperative ClassificationB25C1/06
European ClassificationB25C1/06