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Publication numberUS3115636 A
Publication typeGrant
Publication dateDec 31, 1963
Filing dateAug 11, 1961
Priority dateAug 11, 1961
Publication numberUS 3115636 A, US 3115636A, US-A-3115636, US3115636 A, US3115636A
InventorsJesse Elliott Bernard
Original AssigneeOlin Mathieson
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Explosive tools for driving studs
US 3115636 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

B. J. ELLIOTT EXPLOSIVE TOOLS FOR DRIVING STUDS Filed Aug. 11. 1961 INVENTOR ERNARD JESSE ELLIOT T Dec. 31, 1963 United States Patent O 3,115,636 EXPLSIVE TGLS FOR DRIVING STUDS Bernard .lesse Elliott, Clifton Hill, Victoria, Australia, assigner to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Aug. 11, 1961, Ser. No. 130,938 7 Claims. (Cl. 1-44.5)

This invention relates to explosive actuated tools for driving studs or other fastener elements into walls or other solid surfaces, and more specifically it refers to tools of the kind in which the explosive cartridge is exploded by means of a hammer blow applied to the upper end of a striker member and the driving force of the explosive is transmitted to the fastener element through the intermediary of a piston-like member slidable in the barrel of the tool.

With such tools, it is necessary to provide safety means for locking or holding the striker member to prevent accidental tiring in the event of the tool being dropped or otherwise mishandled. The present invention has for its object to improve upon such safety means whereby they are rendered generally more eicient and less liable to damage and excessive wear in use.

According to the invention, there is provided in a fastener driving tool of the type described, safety means for locking or holding the striker member comprising rollers in engagement with an internal sloped surface and in linear engagement with the curved surface of the shank of the striker member, the rollers functioning with a wedging action to grip the shank of the striker member and the linear contact distributing the gripping pressure along the line of contact with said shank. Y With tools of this kind accidents are possible if the tool should, through carelessness or mistake, be used on walls or surfaces not suiciently solid to hold the fastener. Thus, if the tool should be used on breboard, fibroplaster, plywood or veneered walls, it is possible for the fastener to completely penetrate the wall and continue in free flight, in which case it may strike a workman or ricochet in another direction.

There is provided in a fastener driving tool of the above type, the combination of means for positively connecting the fastener element to the piston-like member prior to firing, and means for arresting the piston-like member in the event of over travel so that the fastener element is automatically arrested should the tool be used on a wall or surface not sufficiently solid to hold the fastener element.

The invention is more fully described aided by reference to the accompanying drawings wherein:

FIG. l is a longitudinal sectional view of a fastener driving tool according to the invention, the safety means being in position to lock or hold the striker member.

FIG. 2 is a similar View to FIG. l, but showing the safety means in released position.

FIG. 3 is a detail View of one of the rollers.

FIG. 4 is a detail View of the roller cage.

As is shownvin these views, the tool comprises a substantially cylindrical barrel 1 within the bore of which are slidably arranged the striker member 2 and the pistonlike member 3. At the upper end, the barrel supports a bearing member 4 through which the shank of the striker member slidably passes.

The bearing member encloses a cage 5 having gaps 6 housing the rollers 7. The cage 5 is acted on by a spring 8 pressing at its lower end on a washer 9 which seats on the top of the cage and also functions to hold the rollers in position in the gaps 6. The upper end of the spring seats against a cap 10 inserted into the upper end of the bearing member and held in position by means such as a C-shaped split snap ring il.

The rollers bear against an internal sloped surface 12 on the bearing member 4 and also against the shank of the striker member 2. They are preferably of the shape shown in FIG. 3, each having a central concave curved surface 13 to Contact with the curved surface of the Shank of the striker member and two end convex curved surfaces 14 to bear against the internal sloped surface 12 which is also curved. The curvature of the surfaces 13 and 14 is such that they closely contact with the shank of the striker member and the internal sloped surface 12 of the bearing member.

The construction of the rollers as above described provides a very eiective locking grip on the shank of the striker member as the rollers are forced into wedging engagement with the internal sloped surface 12 by the spring 8 and linear contact is established over the whole contacting surface. The linear contact of the rollers also reduces damage by scoring and excessive wear on the surface of the shank of the striker member and the sloped internal wall 12 because the pressure is distributed along the line of contact instead of being concentrated at one point as would be the case if balls were used.

The bearing member 4 has holes 15 accommodating release balls 16 capable of engaging the lower end of the cage 5 to move the cage upwardly and release the gripping engagement of the rollers 7 with the striker member shank. The release balls 16 are forced against the lower end of the cage by means of the internal faces of a sleeve 17 slidably encircling the upper portion of the barrel and spring-pressed by a coiled spring 18 normally to the position in which internal gaps 19 in said sleeve register with the release balls. The release balls are thus free and the spring-pressed rollers 7 grip the striker member shank with a wedging action. Said rollers are released prior to firing by moving the sleeve 17 forwardly against the spring 1S so that the internal gaps 19 move past the release balls 16 and said release balls are thus forced inwardly by the internal faces of the sleeve to engage the lower end of the cage 5 and, by forcing said cage upwardly, release the rollers from wedging engagement with the shank of the striker member 2. Said striker member can then be driven downwardly by a hammer blow.

The piston-like member 3 may be constructed as having a longitudinally arranged cavity 20 in its upper end to receive the cartridge, the latter preferably being of the rim fire type. The cartridge is supported by said cavity longitudinally in relation to the piston-like member and with its rim uppermost. Said cavity is preferably arranged eccentrically of the axis of the piston-like member and is opened laterally by a slot 21 to the outer periphery of the piston-like member to enable a suitable tool to be inserted for ejecting the spent cartridge. The lateral slot is of less width than the diameter of the cavity and is arranged at the portion of reduced thickness resulting from the eccentric arrangement of the cavity.

The cartridge, when inserted, has its rim standing clear of the upper end of the cavity and is exploded by the contact of the lower end of the striker member 2 with the cartridge when said striker member is struck by a hammer or the like following release of safety shank gripping means above described.

The piston-like member 3 is withdrawable for loading purposes fromthe lower or muzzle end of the barrel and the fastener element is screwed or otherwise attached t0 the lower end of the piston-like member so that it cannot penetrate completely through the wall or surface into which it is iired and' enter into free Hight.

The lower end of the barrel 1 is provided with safety means to arrest the movement of the piston-like member. Said means may comprise balls 22 mounted in cavities 23 in the side of the barre-l and normally held in protrud- Patented Dec. 31, 1963` ing position to ar-res-t the piston-like member by means of a spring-pressed sleeve 2dencircling the barrel at its lower end. The sleeve has gaps so that, when it is slidably moved rearwardly by Ihand lagainst spring 18, i.e. moved in FIGS. 1 and Z upwardly, the balls 22 are released, enabling the piston-like member 3 to be withdrawn from the lower or muzzle end of the barrel for ejection of the spent cartridge and re-loading.

The pistonalike member 3 has a lower reduced portion 26 against which the balls 22 normally do not engage and an upper portion 27 of normal barrel bore engaging diameter providing a shoulder between portions 26 and 27 which engages the balls when the piston-like member is being arrested.

For safety purposes, further balls 28 may be provided intermediate the group of balls 16 and the group of balls 22 as arresting means above the piston-like member 3 to prevent the striker member 2t from being driven downwardly until such time as the piston-like member is inserted and correctly positioned. The latter balls are also pressed into position by the sleeve 24, the latter having clearance gaps 29* for such safety balls. The arrangement is such that, when the sleeve 24 is in position to release the llower balls 22 to permit withdrawal yof the pistonlike member, the upper balls 23 protrude into the barrel to give protection against the striker member and, when the sleeve is in position to cause the lower balls 22 t protrude into the barrel to function as safety arresting means for the piston-like member, the upper balls 28 are released.

The two sleeves @17 and 24 may be acted `upon by the same coiled spring `18 and may slide one within the other.

Normally, when |the tool is used on a wall or surface of sufficient solidity to hold the fastener element, the fastener element in its penetration of the wall arrests the piston-like member 3 before the upper normal diameter por-tion 27 of the piston-like member engages the balls 22. lf, however, the tool should, through carelessness or error, be used on a wall or surface not sufficiently solid to hold the fastener element, the piston-like member 3 over travels until the shoulder 30 engages the balls 22 and it is thereby automatically arrested. Since the fastener `element is positively connected to the piston-like member 3 by the screwthreaded engagement, the fastener element is likewise arrested. Thus, it is impossible for the fastener element to penetrate into the wall beyond a predetermined distance even in soft or thin wall surfaces, and can never completely penetrate the wall and enter into free ilight beyond the wall.

What is claimed is:

l. In a fastener driving tool of the type having a barrel member with an axially extending bore, a charge of explosive in said bore, an explosive actuated pistonA member carried slideably with a work surface impacting fastener and said explosive in said bore -for axial movement relative to said barrel member to drive said fastener, a striker member carried slideably in said bore and having a shank with a cylindrical surface axially extending into said barrel bore, an impact receiving end and means at the opposite end for tiring said explosive carried in said bore between said members by movement of said striker member relative to said piston member` yunder an impact on said receiving end, and safety means for preventing accidental ring comprising a bearing member having an internal sloped surface axially converging in said -one direction and mounted ron the rearward end of said barrel member idetachiably for slideably receiving said shank and `disposing said sloped surface in axial alignment with said bore, and rollers in linear engagement with said internal sloped surface and with said cylindrical surface of said shank transversely of said bore, a cage between said surface and shank, and a spring acting forwardly on said cage normally pressing the rollers into wedging engagement between said surface and shank, said cage having circumferentially spaced `gaps wherein the rollers are housed, said spring presesd rollers and surfaces normally providing by said engagement a wedging action relative to said striker and barrel members to grip said striker member against movement in said one direction, and said linear engagement distributing all the pressure of said grip along a line of contact extending at least partly about the cylindrical surface, and axially movable means mounted on said barrel member for manual actuation to move said rollers out of said engagement and thereby release said safety means to permit movement of said striker member in said -one direction.

2. The tool fof claim 1 wherein the axially movable means includes a release sleeve with an internally projecting face and a gap and' also release balls carried between the bearing member and said sleeve for engagement of said balls with the front of the cage under the inward press of said face whereby said cage and rollers are forced rearwardly to release the wedging engagement between the rollers, shank, and bearing member, said sleeve being slideably mounted in encircling relationship with the bar- -rel and said bearing member, means normally pressing said sleeve to a position in which said gap registers wi-th the release balls, allowing them to move outwardly and the cage yand rollers forwardly to establish said wedging engagement under the impetus of the forwardly acting spring of the bearing member.

3. The fastener driving tool of claim l wherein the internal sloped surface is circumferentially curved and the rollers each have a central concave curved surface to contact with the curved surface of the shank of the striker member and two end convex curved surfaces to bear against the internal sloped surface.

4. The :fastener fdriving tool as claimed in claim 1 wherein the spring at its forward end presses on a washer seated on the rear of the cage, said spring and washer functioning to hold the rollers in position in the gaps of the cage.

5. In a fas-tener driving tool of the type having an openended barrel with a bore extending axially between a breech opening and a muzzle opening the combination of a fastener-driving piston member received together with la wo-rk surface impacting fastener for axial movemen-t in said bore, said piston member being adapted unider explosive actuation in said bore to drive said fastener in one direction of said movement, a striker member insertable in said barrel at said breech opening, a charge of explosive received in said barrel, said members being slideably movable in said bore relative to each other and said explosive disposed within said bore at a location therein between said members, said striker member having one end adapted to receive an impact for firing said explosive by contact with said members being moved together at said location and in said [direction when said one end is impacted while said fastener is impacted against said surface; means for preventing accidental movement of said striker member in said one direction comprising an internal barrel surface sloped with axial convergence in said one direction, rolling members mounted between said barrel surface and striker member normally urged into wedging engagement in said one direction to grip said striker member against movement in said direction, and axially movable release means including a sleeve member and a cage mounted between said barrel and striker member ffor actuation to move said rolling members in the opposite direction 'out of said engagement permitting movement of said striker member in said one direction; means positivelyl connecting said fastener to said piston member prior to tiring; releasable detent means for arresting said piston member against travel in said direction out yof said location; and control means mounted on said barrel for movement between one position at which said release means is moved in said opposite direction and said striker is free to extend in said one direction to said location to re said explosive, and whereat .said detent means arrests the piston member and fastener against overtravel out of said location, and another position at which the ldetent means ils released to allow removal of said piston member from said muzzle opening and whereat the release means is unactulalted and the movement of said striker member is prevented in said one direction.

6. The tool of claim 5 wherein the piston member has a reduced `front portion with an internally sorew threaded socket providing a positive connecting means ywith a screw threaded end of fthe fastener, and has a rear portion of enlarged -idiameter normally fitting the barrel bore, said portions delininlg a shoulder engageable with the detent means.

7. The tool of claim 5 lwherein the release means includes -a rear group of radially movable balls, the detent means includes a front group of radially movable balls, wherein the control means includes axially movable first and second sleeves supported with both said groups on the barrel, each said sleeve h-aving an intennal protrusion al-ignable with said balls for pressing said balls inwardly and having axially spaced from said sleeve protrusion an internal gap alignable with said balls for allowing the balls to move outwardly, and rneans biasing said sleeves to align the internal gap of said first sleeve normally with said rear group and to align the internal protmsion of said second sleeve normally with said front group, and wherein the tool incluldes intermediate larresting means carried by the barrel and operable by said second sleeve in alltemation with the detent means to extend said intermediate means into said barrel between :said striker member and the piston member passed by said released detent means for removal.

References Cited in the lile of this patent FOREIGN PATENTS 1,221,131 France May 31, 1960

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
FR1221131A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3145387 *Nov 24, 1959Aug 25, 1964Lester Adolph JohnExplosive power assisted hammer driven tool
US3472440 *Nov 25, 1966Oct 14, 1969Hilti AgDevice for driving securing elements into foundations or walls
US3709421 *May 17, 1971Jan 9, 1973Impex Essen VertriebCartridge-actuated fastener-driving tools
US4941391 *Jun 12, 1989Jul 17, 1990Hilti AktiengesellschaftDriving piston braking means for explosive powder actuated setting device
US6889884 *Jan 29, 2002May 10, 2005Hilti AktiengesellschaftSetting tool
U.S. Classification227/10
International ClassificationB25C1/14, B25C1/18, B25C1/00
Cooperative ClassificationB25C1/146, B25C1/188
European ClassificationB25C1/14C, B25C1/18C