US3711008A - Impact tools - Google Patents

Abstract

Manual and pneumatically operated impact tools for driving fasteners into concrete through the utilization of the kinetic energy of a hammer impacting a driver. The tools are adapted to insure the perpendicularity of the fasteners and to drive the fasteners in close proximity to a wall or vertical surface.

Description

United States Patent [191 Clifford et al. 1 Jan. 16, 1973 1541 IMPACT TOOLS 2,557,000 6/195] Holmes ..227 147 x 3,060,440 10/1962 Pfaff et al. ..227 147 [76] lnvemors- 23 Fwy Acres 3,060,441 10/1962 Henning ..227 147 Dflve, Wayland, Mass- 01778; 3,498,517 3 1970 Novak ..227 130 x Harry M. Haytayan, Sunnside Lane, 3,595,460 7/l97l Pitkin ....227/l30 X Lincoln, Mass. 01773 3,570,738 3/1971 Pabich ..227 120 X Filed: Aug. 31, 1970 Appl. No.: 68,423

US. Cl ..227/147, 227/130 Int. Cl .;.B25c 7/00 Field of Search ..227/129, 130, 140, 147

References Cited UNITED STATESPATENTS 5/1962 Goldring ..227/130 X Primary ExaminerGranville Y. Custer, Jr. Attorney-Donald F. Daley [57] ABSTRACT Manual and pneumatically operated impact tools for driving fasteners into concrete through the utilization of the kinetic energy of a hammer impacting a driver. The tools are adapted to insure the perpendicularity of the fasteners and to drive the fasteners in close proximity to a wall or vertical surface.

2 Claims, 6 Drawing Figures PATENTEDJAM 16ms 3. 711 008 I SHEET 30F 3 INVENTOR. HA RR y m HAYTAYA M ND PAUL CLIFFOED IMPACT TOOLS BACKGROUND OF THE INVENTION The present invention relates generally to impact tools for driving fasteners and the like, and specifically to manually and pneumatically operated impact tools for driving fasteners into concrete or other masonry surfaces.

Though the present invention is specifically intended to drive fasteners into concrete or hard, brittle surfaces, it is usable in driving fasteners into wood or other structural material. Nail or fastener driving devices are well known for applications such as laying hardwood flooring where nails are driven through wood boards into a wood subflooring. The impact tools used for this type of application usually consist of large bulky devices which are not suited for driving nails into concrete or hard, brittle surfaces.

Conventional nailing machines utilize a brute force technique where the piston area is made large enough to generate the necessary force to drive the nail into the woodpiece. The present invention utilizes not only the force generated by the action of the high pressure air on the piston, but it also utilizes the kinetic energy of the piston. This kinetic energy is generated by allowing .the piston to pick up velocity before it contacts the driver.

The present invention is particularly adapted for use in the installation of the small wooden strips used to hold wall to wall carpetingto concrete. Wall to wall carpeting is normally held in place by 1 wide and A" thick strips of wood secured to the flooring near the wall. These strips of wood have small tacks extending upward to grip the carpet and must be mounted very close to the wall or baseboard. Normally they are mounted A from the wall. The means presently used to install this stripping are explosive guns and manual hammers. The explosive technique is costly because of the cartridge expense and loading time required after every nail insertion. The manual technique is also costly because it requires the services of a skilled operator and is slow because of nailing accuracy requirements and the number of hammer blows required per nail. Skill is required to prevent or minimize damage to the baseboard or wall and chipping of the cement.

In order to use an automatic or manually operated impact device to secure the strip as close to the wall as possible, the impact device must be small in diameter, easily positionable and capable of positioning the strip without damaging the tacks or the wall or the baseboard. It should also be capable of automatically positioning the strip a specific distance from the wall and still drive the nail or fastener perpendicular to the flooring. These aspects are particularly important when the strips are to be secured to concrete flooring, since the nail should be driven with one blow and driven perpendicular to the floor so that the concrete does not chip and the nail does not bend.

It is therefore an object of the present invention to improve impact tools for driving fasteners or the like and to provide an impact tool which is relatively small in diameter and which will drive fasteners or nails into hard, brittle surfaces such as concrete with one sharp blow. It is a further objectof this invention to provide an impact tool for use in positioning and fastening wooden strips to concrete or other surfaces. It is a further object of this invention to provide an automatic impact tool which positions a nail perpendicular to a surface and drives the nail into the surface with one blow.

These and other objects of the invention are attained by meansof an impact tool having an automatic nail feeding and positioning device wherein a nail or fastener is positioned in close proximity to an anvil or driver which transmits the driving forcefrom a piston or hammer to the nail. The piston is mounted in a cylinder directly above the driver and movable into contact with the driver to provide the driving force. The movement of the piston is sufficient to produce the kinetic energy necessary to drive the nail into concrete or other hard surface. Means are provided to operate the piston manually or pneumatically.

For a better understanding of the invention as well a other objects and features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is an isometric view of a manually operated impact tool embodying the present invention.

FIG. 2 is a side view of the impact tool shown in FIG.

1, with portions broken away to internal structure.

FIG. 3 is an isometric view of a pneumatically operated impact tool embodying the present invention.

FIG. 4 is a side sectional view taken along lines 4-4 of FIG. 3.

FIG. 5 is an enlarged view ofa portion of FIG. 4.

FIG. 6 is a partial sectional view of the magazine" taken along lines 66 of FIG. 5.

FIG. 1 of the drawings shows a manually operated impact tool utilizing the present invention. A housing ormain body 2 which provides the structural support for the impact mechanism is mounted above thedriver housing 3 which includes positioning guides for aworkpiece 6. Themain body 2 and thedriver housing 3 are shaped so that oneouter surface 4 will fit flush with a wall or baseboard 1. When theworkpiece 6 is wall to wall carpeting attachmentstrips, the workpiece is accurately positioned from the wall by means of thelegs 5 on the bottom of thedriver housing 3. The lower end of thedriver housing 3 has achannel 8 extending therethrough parallel to thesurface 4. Thechannel 8 is large enough to receive aworkpiece 6 and has anedge guide 10 which gauges and positions theworkpiece 6 relative to thesurface 4.

Manual Impact Tool In order to drive a nail or fastener into theworkpiece 6 there is shown in FIG. 2 an axially alignednail slot 12 extending downward through anail guide member 14. The length ofguide member 14 is determined so that it contacts or is in close proximity with the surface through which the nail is to be driven. The length of thenail guide 14 and the depth and width of thechannel 8 can be varied for specific specialized applications.

Theslot 12 is sized to receive and guide a nail or fastener 18. Nails are fed from a spring-loaded cartridge ormagazine 20 through anail track 22 in the magazine to a positioning station which consists of an opening extending downward through thehousing 3 into theslot 12. Theslot 12 is rectangular shaped and thenail 18 has a teeshaped head so that the nail is held in place in the slot by the pressure exerted by nails being urged into the slot from a magazine. The tee shaped head allows passage of the nail through theslot 12 when impacted by adriver 30. Themagazine 20 is attached to thehousing 3 by appropriate fasteners, and may be of any type which automatically supplies nails to theslot 12 as each nail is driven into theworkpiece 6.

Referring to FIG. 6, acavity 17 inhousing 3 contains aspring 19. The spring is attached to thehousing 3 by a shoulder screw. Alever 21 is attached to the end of thespring 19 and is also connected to aplunger 23, seen in FIG. 6, that travels in thenail track 22. The plunger contacts thenails 18 in thetrack 22 and through the action of the spring indexes the nails automatically to the positioning station andslot 12 as each nail is driven into theworkpiece 6. The nails may be bonded together for ease of loading. Thelever 21 is easily removed from thenail track 22 by drawing theplunger 23 out of the magazine against the action of the spring. The length of thenail guide 14 and the depth and width of thechannel 8 can be varied for specific specialized applications.

Thedriver housing 3 has a lower portion consisting of aworkpiece guide channel 8 and four legs forming thechannel 8. Thelegs 5 together with themagazine support leg 25 provide stability and perpendicularity for the entire tool. With thelegs 5 and 25 resting on the surface into which a nail is to be driven, the nail will be perpendicular to the surface. Thedriver housing 3 has adriver guide track 28 extending downward through the housing to thenail slot 12. The guide track is sized and shaped to accommodate sliding movement of adriver 30. Thedriver 30 has anenlarged body portion 32 which mates with theguide track 28 for vertical. sliding movement. The lower end of thedriver 30 has a reducedrectangular impact head 34 extending downward into theslot 12. The end of theimpact head 34 is positioned slightly above .the head of anail 18 positioned in theslot 12 when the driver is in an elevated position. When the driver is driven downward, the impact head contacts the nail inslot 12, driving it downward into theworkpiece 6. Between theenlarged body portion 32 and theimpact head 34 of the driver, there is ashoulder 36 positioned to engage aresilient bumper 37 to limit the downward movement of the driver. Above the enlarged body portion of the driver there is adrive head 38 extending upwards into themain housing 2.

Themain housing 2 is tubular shaped with the interior of the tube adapted to receive and guide, for sliding movement, ahammer member 40. Thehammer 40 consists of a rod shapedmain body 42 sized for sliding movement within the upper portion of thehousing 2, ahardened impact head 44 extending downward from themain body 42 to impact thedrive head 38 of the driver, and ahandle 46 secured to the upper portion of themain hammer body 42.

In operation, the impact tool is positioned over a workpiece by gripping thehandle 46 and themain housing 2. Theworkpiece 6 is positioned by abutting thesurface 4 of thehousings 2 and 3 against a wall or baseboard. Raising thehandle 46 elevates thehammer 40 within the tubularmain housing 2 allowing aspring 50 incavity 52 to urge the driver upwards until theenlarged body portion 32 of the driver contacts stop 54. The hammer is raised above the anvil a distance sufficient to permit enough kinetic energy to be developed when the hammer is moved downwards to drive anail 18 into the workpiece and flooring. With the anvil in the elevated position, anail 18 is indexed through thetrack 22 into theslot 12 by thespring 19 of themagazine 20. Thehammer 40 is rapidly brought downward by movement of thehandle 46 so that theimpact head 44 of the hammer contacts thedrive head 38 of the driver. The kinetic energy of the hammer is imparted to thedriver 30 and the driver is driven downward withdrive head 34 in contact with thenail 18 inslot 12. One sharp movement of the hammer is sufficient to drive the nail through the workpiece into concrete or masonry surface.

Pneumatic Impact Tool FIGS. 3 and 4 show a pneumatically operated fastener driving tool consisting of anupper housing member 102, amain housing 104, adriver housing 103, an airinlet assembly unit 106 and anactuating trigger 108. Thedriver housing 103 extends downward terminating in a workpiece positioning member of the same structure as that shown in FIGS. 1 and 2 and described relative to the manual impact tool. A cassette ormagazine 112 is attached to thedriver housing 103 and automatically provides nails or fasteners into themain housing 104 in the same manner previously described.

Within themain housing 104 there is a cylinder 1 14 which extends from theupper housing 102 downward to a point in the lower portion of themain housing 104 where it abuts ashoulder 116. The cylinder 114 is pneumatically sealed by an O ring positioned in a slot in the lower portion of the cylinder and bearing against the inner surface of themain housing 104.

Within the cylinder 114 there is apiston 126 adapted for movement throughout the length of the cylinder 1 14.Piston 126 consists of amain stem 128 which is of smaller diameter than the two ends of thepiston 130 and 132. The ends of thepiston 130 and 132 are sized for intimate sliding movement within the walls of the cylinder 114. The cylinder 114 has a largerinternal diameter 134 in the upper portion of the cylinder and a smallerinner diameter 136 in the lower portion of the cylinder. The ends of thepiston 130 and 132 are thus of different diameter with the upper portion of thepiston 130 being larger than thelower portion 132. This difference in size between the two ends of the piston provides the differential force necessary to propel the piston upward when the tool is pneumatically energized. Thepiston 126 is pneumatically sealed within the cylinder 114 by means of a pair of 0rings 138 and 139. The lower end of thepiston 126 has a hammer orimpact head 140 secured on the end thereof. In its lowermost position theimpact head 140 rests on a resilient bumper I42 limiting the downward movement of thepiston 126.

Referring to theupper housing 102, there is mounted therein anupper piston 144 having apressure bearing surface 146, aguide stem 148 and arelease vent 150 extending through the length of thepiston 144. Theguidestem 148 isfitted for movement within abearing surface 152 within thehousing 102 and is pneumatically sealed by means of anO ring 154. Upward movement of thepiston 144 is limited by aresilient bumper 156 in the upper end of theguide cylinder 152. The lower or main portion of thepiston 144 is sealed within a major cylinder 158 by means of a pair ofrings 160 and 161. The lower portion of the upper piston has aresilient seal 162 which acts as a bumper and seal for themain piston 126 at the upper end of the main piston stroke. Achamber 164 is formed within theupper housing 102 by the cylinder 158 and thebearing surface 146 of theupper piston 144. The upper portion ofpiston 144 is larger than the lower portion of the same piston. Pneumatic pressure within thechamber 164 provides the differential force necessary to drive thepiston 144 downward against the main cylinder 114 providing a seal for the upper end of the cylinder 114 and a stop for themain piston 126 in its upward movement.

Within the lower end of themain housing 104 there is a driver stem 170 extending upwards from an anvil ordriver 171 and positioned within asmall diameter cylinder 172 in themain housing 104. The anvil stem extends from a point wherein it will be contacted by theimpact head 140 on the end of thepiston 126 when the piston is in its lowermost position to a point immediately above the head of a nail orfastener 18 positioned within the impact tool at the positioning station. The anvil stem is surrounded by acompression spring 174 which bears against a retaining ring 176 in the anvil stem and aflange 178 located between the lower portion of themain housing 104 and thedriver housing 103.Flange 178 also limits the upward movement of thedriver 171. Downward movement of thepiston 126 causes theimpact head 140 to strike the upper end of the driver stem 170, which in turn imparts the force to the head of the nail orfastener 18.

Thefastener supply assembly 112 and the positioning of thenails 18 and theworkpiece 6 are the same as previously described for the manual impact tool. Thedriver housing 103 has legs which together with leg on themagazine 112 provide perpendicularity to the tool and nails. Thesurface 4 on thehousings 103 and 104 provide alignment with a wall or baseboard and positioning of theworkpiece 6 relative to the wall or baseboard.

Pneumatic System Thepneumatic supply assembly 106 is mounted within ahandle 200. Thehandle 200 is adapted for holding and positioning the impact tool and for coupling to a high pressure air source. The end of thehandle 200 has thesuitable connectors 202 for connection to an outside high pressure air source not shown. Air flows from the high pressure source into the handle wherein a highpressure reservoir chamber 204 is provided. Within the handle aball valve assembly 206 is positioned to be actuated by thetrigger 108. The ball valve assembly consists of aball 208 mounted within a valve chamber 210. An actuating pin 212 extends from thetrigger 108 upward through anopening 214 in thevalve 206 into contact with theball 208. High pressure air from thereservoir 204 flows through anopening 216 into the chamber 210 and exits through an opening 218. The high pressure forces theball 208 downward within the chamber 210 against theresilient sealing ring 236 thus allowing the air to pass through theopening 216 into the chamber 210 and out the opening 218. Actuating thetrigger 108 forces the rod 212 upward, which in turn forces theball 208 upward against the resilient ring 220 surrounding theopening 216 and sealing off theopening 216. Release of thetrigger 108 allows the air under pressure inreservoir 204 to force theball 208 back downward, thus opening theflow of air through theopening 216 to the chamber 210 and out the opening 218. When the trigger is actuated and theball 208 is forced against theopening 216 cutting off the air supply, the air in the chamber 210 and the passage 218 are vented to atmosphere through theopening 214 for the rod 212 by means of anair vent 222.

Operation In operation, the high pressure source is connected to theair inlet connectors 202 in thehandle 200 of the impact tool. The air enters thereservoir 204 and passes through thepassage 216 to the passage 218 of thevalve assembly 206 and then through thepassage 231. The air enterschamber 164 and forces thepiston 144 down against cylinder 114. Simultaneously, the high pressure air enters theair accumulator 234 through apassage 230 in themain housing 104. The high pressure air then enters the main cylinder 114 throughholes 238 and lifts the piston upward against therubber seal 162 of theupper piston 144. Achamber 234 surrounds the cylinder 114 and extends upward to the lower portion of theupper housing 102. Thechamber 234 is open to the top end of the cylinder 114 when theupper piston 144 is in the upward position. Theupper piston 144 seals the cylinder 114 from thechamber 234 when it is in its downward position. At this time the anvil stem 170 is held in the raised position by thecompression spring 174. In the pneumatic system, thevent port 222 of thevalve body 206 is sealed off by theball 208 being forced downward against aresilient sealing ring 236 surrounding the stem 212. The high pressure air in thechamber 164 above the upper piston forces the upper piston downward into the position shown in FIG. 2 sealing off the cylinder 114 from theaccumulator chamber 234. The high pressure air in the accumulator passes through a series ofopenings 238 in the cylinder wall 114 into thechamber 240 formed by the undercut portion of thepiston 126. The high pressure air in thechamber 240 causes the piston to move upward due to the difference in diameter of the upper portion of thepiston 126 and thelower portion 132. Air within the cylinder 114 above thepiston 126 is vented to atmosphere through the opening in theupper piston 144 and theair vent line 242 provided in theupper housing 102 to theguide cylinder 152. The downward or sealing movement of theupper piston 144 is achieved by means of the differential in the diameter of the upper piston exposed to the high pressure air in thechamber 164 and that exposed to the high pressure air in the cylinder 114 and theaccumulator 234.

Actuation of thetrigger 108 forces the rod 212 to move thevalve ball 208 upward against the resilient member 220 in theopening 216. Theball 208 cuts off the high pressure air supply and vents thechamber 164 above theupper piston 144 through thepassage 231, through 218, the valve chamber 210 and theair vent 222. The venting action ofchamber 164 causes a differential in pressure between the upper portion of theupper cylinder 144 and the lower portion of theupper cylinder 144 that is exposed to the high pressure air of theaccumulator 234. The unbalanced force generated causes the upper cylinder to move upwards, thus cutting off thevent 242 and exposing the top of the cylinder 1 14 to the high pressure air in theaccumulator 234. The high pressure air in theaccumulator 234 is then exposed to the top surface of the upper portion I30 of the piston I26. causing thepiston 126 to move in a downward direction. This downward movement results from the difference in diameter between theupper portion 130 and thelower portion 132 of thepiston 126. As thepiston 126 moves to its downward position theimpact head 140 contacts the anvil stem 170 which imparts the kinetic energy produced by the movement of thepiston 126 to the head of the nail or fastener and drives it into thewood strip 6 and the concrete or masonry surface. The downward movement of thepiston 126 is arrested by theresilient bumper 142.

Release of thetrigger 108 allows the high pressure air to move theball 208 downward within the chamber 210 against theresilient sealing ring 236 thus sealing off thevent 222 and energizing the impact tool for its next operation by moving thepiston 126 upward and theupper piston 144 downward to the sealing position. The anvil stem is'returned to its uppermost position by means of thecompression spring 174. A new nail or fastener is automatically inserted into position by the cassette or magazine and the operator merely moves the tool to the next position preparatory to actuating the trigger and driving another nail.

While the invention has been described with reference to the structures disclosed herein, it is not confined to the specific details set forth, since it is apparent that many modifications and changes can be made by those skilled in the art. This application is therefore intended to cover such modifications or changes as may come within the purposes of the improvements or scope of the following claims.

What is claimed is:

1. An impact tool for driving fasteners through a workpiece into masonry surfaces or the like including:

a driver housing having means to locate a workpiece in a position to receive a fastener above the workpiece and means to align the impact tool so that a fastener in the positioning station is substantially perpendicular to the surface into which the fastener is to be driven, including four leg members extending downward from the driver housing in a position to straddle the workpiece and a fifth leg member remote from the driver housing to provide stability;

a driver positioned in the driver housing immediately above the fastener positioning station and movable downward through the fastener positioning station; 1

means to impact the driver with a velocity sufficient to force the driver downward through the positioning station displacing a fastener in the positioning station; and

fastener supply means adapted to position and hold a fastener in the positioning station in the driverhousing for each operation of the impact tool. 2. The impact tool of claim 1 wherein the fifth leg member is attached to and extending downward from the fastener supply means.

Claims (2)

1. An impact tool for driving fasteners through a workpiece into masonry surfaces or the like including: a driver housing having means to locate a workpiece in a position to receive a fastener above the workpiece and means to align the impact tool so that a fastener in the positioning station is substantially perpendicular to the surface into which the fastener is to be driven, including four leg members extending downward from the driver housing in a position to straddle the workpiece and a fifth leg member remote from the driver housing to provide stability; a driver positioned in the driver housing immediately above the fastener positioning station and movable downward through the fastener positioning station; means to impact the driver with a velocity sufficient to force the driver downward through the positioning station displacing a fastener in the positioning station; and fastener supply means adapted to position and hold a fastener in the pOsitioning station in the driver housing for each operation of the impact tool.

2. The impact tool of claim 1 wherein the fifth leg member is attached to and extending downward from the fastener supply means.

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