US3263429A

US3263429A - Recoilless, jet driven hammer

Info

Publication number: US3263429A
Application number: US312401A
Authority: US
Inventors: Null Fay Edison
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-09-30
Filing date: 1963-09-30
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02

Description

Aug. 2, 1966 F. E. NULL RECOILLESS, JET DRIVEN HAMMER 3 Sheets-Sheet 1 Filed Sept. a0, 1963 IN VEN TOR. E.,Null

F. E. NULL Aug. 2, 1966 RECOILLESS, JET DRIVEN HAMMER 5 Sheets-Sheet 2 mm 3 EN U L nww mm C n1 mm b ww mw mam ww q mm g m 2 MN a w 9 W i q ow 2 E l X mi N IF H E N H. m f h Y P B i v o. B mm .L t: m 2 8 3 mm o Filed Sept. 30, 1963 mm wm wk mu.) N il q v@ m n mN Aug. 2, 1966 F. E. NULL RECOILLESS, JET DRIVEN HAMMER 5 Sheets-Sheet 5 Filed Sept. 30, 1963 INVENTOR. F5 EN u H BY w w a 3 a vm wN I United States Patent r 3,263,429 RECOILLESS, JET DRIVEN HAMMER Fay Edison Null, Choctawmar Subdivision, Fla. (Box 158, Shalimar, Fla.) Filed Sept. 30, 1963, Ser. No. 312,401 Claims. (Cl. 60-625) This invention relates to the acceleration of hammer type tools by jet drive, with elimination of recoil forces. The basic hammer drive can be applied to a number of tools, such as a pick for breaking up concrete, a maul for driving posts, a chisel for grubbing out roots of trees where there is not room for a band saw, and for driving nails of any size.

Portable, power hammer action before the present invention was based on the pressure of a fluid driving a piston down a cylinder, orupon the release of a distorted spring, or upon electric motor torque or solenoid thrust; in any case there was a back thrust or torque equal and opposite to the force driving the piston, or to the force of the distorted spring or the electromagnetic force on the accelerated part. These recoil forces have limited the effectiveness of portable, power tools of the hammer type. Elimination of the recoil forces by a jet drive permits the impulse (forcextime) delivered to the work in a hammer blow to be increased by orders of magnitude while maintaining or increasing the hammer blow frequency. This reduces the number of man hours required for hammer type work by an order of magnitude or more.

Although magazine loading of rocket powder cartridges could be used, compressed air has the advantage of simplicity and the absence of a dangerous, high temperature exhaust. The specific impulse (lb. thrust/lb. propellant) of rocket powder is much higher than for compressed air, but it is also much moreexpensive. The efficiency of a jet is notoriously poor when moving at the low velocity of the hammer stroke, e.g., at 100 ft. per sec. Thus, the jet hammer will require many more kilowatt hours than the piston type; but electrical energy is generally cheap compared with labor, and as the impulse per hammer stroke can be increased by orders of magnitude for the jet driven type, the consequent large reduction in the required manhours for the job will give an overall, large cost saving.

The strokes of the jet and the tool can be separated by attaching the jet to a separate drive piston which reaches maximum velocity at the end of jet exhaust from a small tank mounted on said drive piston. The drive piston impacts the tool piston by compressing a column of air of adjustable length between said pistons which slide in a cylinder which is an integral part of the hammer frame. Different stroke lengths are obtained for the tool (mounting) piston and the jet drive piston. The mass of the drive piston (including the air tanks and jet nozzle) is equal to that of the tool piston (including the tool), so that upon lossless impact of the said two pistons (across a column of compressed gas), the drive piston is brought to rest and the tool piston is accelerated to the velocity of the drive piston before impact. As the magnitude of the gas pressure on the said two pistons is equal during impact, and the same kinetic energy is received by the tool piston as given by the drive piston, the distance required during impact to accelerate the tool piston must be equal to that to decelerate the drive piston. This distance is made equal to the required stroke of the tool piston, before it hits the work, so that the drive piston can be stopped without bounce or overshoot. The distance the drive piston moves against the compressed gas during impact is varied by the position of a vent in the impact cylinder; the drive piston only appreciably compresses the gas after it passes the vent opening. The free stroke of the tool piston is then also controlled by the vent position.

The drive piston is stopped relatively close to the initial position of the tool piston; the compressed gas pressure is only high enough to supply an effective force when the distance between said pistons is small.

Thus, the initial separation between the work and a nail might be of an inch (permitting spotting the nail position with reasonable accuracy) while the jet driven piston might be accelerated over a distance of 12 inches; this would permit the opening time of the valve in the jet nozzle to be longer, with much less required accuracy. A long strokeof the jet drive reduces the ratio of the valve opening time in the nozzle to the total exhaust time, giving greater efficiency, and making possible a lighter weight tool for the same impact impulse.

The driver piston mounts a small tank that supplies enough compressed gas to the nozzle for the required thrust per stroke. At the end of each impact of the drive piston and the tool piston, the drive piston with its tank and jet nozzle are returned to the initial position relatively slowly by weak springs. The tank intake makes a sliding contact with the gas fill valve supported from the frame of the tool, and an arm on the tank actuates a lever to open the inlet valve as the tank slides into its ready position. The jet supply tank is thus reloaded automatically, and the jet is ready to fire as soon as the slide valve in the jet nozzle is released (under spring and air pressure) by a manual trigger. This feature permits the operator to fire the hammer blow when the tool is at the proper distance and direction relative to the work, as in spotting the position of a nail or the angle of a root cutting blade.

If the jet were fired accidentally when not positioned on the work, the whole tool would give a powerful blow in the direction the tool was pointing. To provide backup safety to the trigger release a cocking mechanism is provided, which at the same time allows selection of the strength of each hammer blow in a ratio of about 1 to 4. After the tool has been returned to normal position by light springs, a small plunger attached to the end of the tool frame may be pressed against the work the proper amount to hydraulically actuate the toggle-type valves of the required number of small gas tanks, said valves connecting them to a common manifold to supply the proper gas pressure to the jet drive piston tank, and the desired thrust for a given hammer stroke. The toggle-type valves are held in the jet tank connected position by gas pressure until the drive piston starts its forward stroke and the gas is exhausted to atmospheric pressure; thus, pulling the plunger back from the work .by placing the tool in the firing position has no effect on the cocking setting. As the cooking plunger is pressed against the work to consecutive values of its four positions, the corresponding toggle-type valves of consecutive, small gas supply tanks are clicked into the jet tank connected position,

e.g., at the fourth click the operator knows that his tool is cocked for maximum thrust and impact impulse as supplied by four small gas tanks, now all connected to supply a relatively high gas pressure to the jet tank.

It is therefore, among the objects of the present invention to provide a jet drive for a hammer stroke type, portable tool that will eliminate recoil forces, and permit orders of magnitude increase in the impact impulse between the tool and work.

Another object of the I present invention is to permit different stroke lengths of the tool piston and the jet accelerated drive piston, by utilizing an impact across a compressed gas gap in a cylinder between equal mass drive piston and tool piston, so that the drive piston will be brought to rest without recoil, and the tool piston will be freely accelerated to its maximum velocity by the time it hits the work, its kinetic energy being absorbed in the work impact.

ing valve in the jet nozzle to open rapidly under combined spring and gas pressure.

Another object of the present invention is to provide a safety check on accidental trigger release by a cocking mechanism, which also selects the desired thrust for a given stroke. A cocking plunger on the end of the tool frame can be set in four different positions by variable pressure between it and the work. The movement of the cocking plunger activates toggle-type valves to the on position in sequence, each valve connecting a small tank of compressed gas to the inlet valve of the jet tank, hence, effectively controlling the pressure of the gas in the jet tank and the thrust of the hammer stroke.

Objects and advantages other than those set forth will be apparent to those skilled in the art from the following description used in connection with the accompanying drawings, in which:

FIG. 1a shows the rear end view of the essential operating mechanism of the hammer in the initial, cocked position, but without handles and gas supply connections. Portions of the supporting frame have been torn away to show the jet exhaust nozzle and sliding valve for the jet nozzle.

FIG. 2a is a cross-sectional view of the hammer shown in FIG. 1a; it shows the cocked position of the jet propelled drive piston, and the retracted tool position. The tool piston mounts a pavement breaking pick. The tool frame and jet exhaust deflector are shown partially broken away to clearly show the jet nozzle pressure plate forced inward against the nozzle slide valve.

FIG. lb is a rear end view of the tool mechanism at the end of the drive piston stroke after it has been stopped by transfer of its kinetic energy to the tool piston by a gas cushioned impact. The supporting frame is partially broken away for a clearer view of the jet exhaust nozzle and the nozzle slide valve.

FIG. 2b is a cross-sectional view of FIG. 1b, showing the drive piston after it has been stopped at the end of its stroke, and shows the tool piston flying toward the work with the original velocity of the drive piston.

FIG. 3 is a rear end view of the frame alone, with both the drive piston, jet tank, and the tool piston removed.

FIG. 4 is a plan view of the frame alone, but including the cylinder in which the drive and tool pistons slide, the supporting frame and guide for the jet tank, and the fixed cylinder for the drive piston return spring. The cylinder cooling jacket and water tank are also shown, positioned where the drive and tool pistons impact against a separating air cushion with an appreciable rise in temperature.

FIG. 5 shows an elevation view, schematic of the basic hammer equipped with a pick tool for breaking up a concrete layer over sand (said layers shown in crosssection). The thumb activated trigger release is shown on the handle. A schematic is given of the compressed gas source with the cocking plunger on the frame of the hammer to connect to the jet tank the number of gas tanks required for the desired pressure and thrust.

FIG. 6a illustrates a central, cross-sectional view of a post driving tool, screwed into the end of the tool cylinder.

FIG. 612 indicates a central cross-section of the tool of FIG. 6a applied to driving a post or pile, shown in elevation.

FIG. 7a gives a central, cross-sectional view of a tree root grubbing blade screwed into the end of the tool cylinder.

FIG. 7b is an elevation schematic of the application of the tool of FIG. 7a to the close quarters of the grubbing operation.

FIG. 8a is a central, cross-sectional view of a nail driving tool which has been screwed into the end of the tool piston. It shows the permanent magnet circuit that holds the nail in position against the tool so that it can be spotted on the work below.

FIG. 8b is an elevation view of the tool and nail at the end of the tool drive stroke, the work being shown in cross-section.

FIG. is an elevation view of the tool and nail after the tool has been retracted for driving another nail. The work is shown in cross-section.

Referring more particularly to the drawings by characters of reference, reference numeral 1, FIG. 2a, is a cylinder in which jet drive piston 2 and tool piston 3 slide with a gas tight fit. Piston rings 4, held by screwon ring 7, and piston rings 5 held by back plate 6 insure a low piston leakage. Spring 8 and stop ring 9 prevent the drive piston 2 from sliding out of cylinder 1, and spring 10 and ring stop 11 prevent the tool piston from leaving cylinder 1. Cylinder 1 is an integral part of the frame, being attached to

circular plates

12 and 12a which are braced by fins 13. The largest circular plate 12 is welded or brazed to the lattice beam frame 14, FIGS. 4 and 3, which forms a guide for the jet tank 28, and supports the jet tank loading equipment 80, FIG, 1a, by support 73, FIG. 4, and trigger mechanism 81, FIG. 2a, by the support 38, FIGS. 4 and 2a. For clarity FIG. 2a shows the rear of the lattice beam 14 and jet deflector 37 broken away to show the jet nozzle 30, pressure plate 33, and slide valve 31. The dotted lines behind the jet tank 28 show the position of the lattice beam 14 with the projections 82 on the jet tank 28 riding in the recesses formed by the latticework of beam 14.

Reference numeral 15, FIG. 2a is the tool plug that can be replaceably screwed into tool piston 3. The pick 16 for crushing concrete is attached to plug 15 by means of screw 17 and nut 18. The posts 19 limit the inward travel of tool piston 3 under the tension of springs 20. Small screw plugs 21 in cylinder 1 permit opening or closing openings to cylinder 1 to allow escape of gas driven in front of piston 2 until piston 2 reaches the opening, thus effectively determining the initial length of gas column 147a compressed between

pistons

2 and 3. The cooling jacket 24 receives fluid from opening 83 to tank 23 which is under gas pressure from connection 22. Rotation of the rear end of the hammer of FIG. 2a, out of the paper puts the opening 83 at the bottom of tank 23 with the pressurizing gas from inlet 22 at the top, so that the air does not escape past the cooling water 147 being driven down through the opening 83. Small holes 25 in inner cooling jacket wall 25a, produce liquid sprays 26 that cool the wall 1a of cylinder 1 by evaporation and escape as gas at 27.

The jet, compressed gas tank 28, is attached to drive piston 2, plastic pads 29 taking up accidental, residual shock from impact of tank 28 and plate 12. The jet exhaust nozzle 30 has its entrance 28a in the wall 28b and its mouth 280 in fixed pressure block 33 which is pressed against slide valve 31 by levers 36 which are pivoted at the bases of ends 34 and pulled inward by springs 35. Blocks 37 attached to the tank 28 prevent the pressure block 33 from sliding up or down so that the mouth 28c of nozzle 30 is always aligned with the entrance 28a. The slide valve 31 that moves up and down between the nozzle entrance 28a and the month 280 of the nozzle 30 in pressure block 33, is closed in FIGS. la and 2a, the slot opening being shown at 32.'

The slide valve 31 is guided at the bottom by blocks 66a and at the top by piston rod 60 attached to the piston 61 that slides in cylinder 39 against the compression of spring 62 and compressed gas 63a from inlet 63 from the jet tank 28.

In the pre-stroke position of drive piston 2, slide valve 31 is held in the closed, upper position by ramp 49 which is secured by notched trigger release 58 until actuated by flexible wire (in conduit) control 59, which goes to the handle 46 on frame 14 for thumb actuation of lever 45 in FIG. 5. When trigger 58 is pulled back around pivot 55 the rear of lever 50 flies upward as ramp 49 is depressed by the downward force of slide valve 31, which is light weight and thin, so that under the force of spring 62 and pressure of air 63a from inlet 63, it can be quickly depressed so as to bring opening 32 into the nozzle 30 between inlet 28a and mouth 28c, making the valve opening time small compared to the time for the drive piston stroke and jet exhaust. This assures that the inefiicient, exhaust condition for a partially open valve lasts for only a small fraction of the total exhaust time. As the drive piston 2 is propelled forward and slide valve 31 breaks contact with ramp 49, spring 53 rotates the ramp 49 back to its pre-stroke position against stop 54. When thumb lever 45, FIG. 5 is released by the operator, spring 53a returns trigger 58 to the normal position over lever 50 and against stop 54a. If trigger 58 returns to its prestroke position before ramp 49, the end of lever 50 will engage the sloped surface of trigger 58 to push it back until lever 50 is in the pre-stroke position against stop 54. Thus the trigger mechanism 81 is automatically reset for the next stroke by spring action, and as the drive piston 2 is returned to its initial position for another stroke, the bottom of slide valve 31 engages ramp 49 and is driven upward compressing spring 62. The valve aperture 32 is made larger than the diameter of the entrance 28a of nozzle 30 to prevent the oscillation that might occur for a suddenly stopped slide valve 31. Overshoot of the bottom of aperture 32 past the bottom of the entrance 28a of nozzle 30 is permitted but with a high rate of damping provided by piston rod 64 attached to slide valve 31 and to piston 65 sliding in damping cylinder 68. As piston 65 starts downward the inclosed air can partially escape through large holes 67, but as piston 65 reaches the lower part of cylinder 68, the air can only escape through small holes 66 with a resultant high compression of the inclosed gas with a large damping force.

As the jet tank is returned to its initial position the fiat, ground surface of projection 69, FIG. la, on jet tank 28 slides under the rounded edge of cap 48 which also has a ground surface and slides upward on tube 72 against pressure from spring 71. The ground surfaces of projection 69 and cap 48 form an air tight seal before the lower end of tube 72 partially overlaps the opening of the check valve 70 in projection 69. As jet tank 28 slides into its initial position, knob 78 attached to the top of tank 28, rotates lever 76 against the pull of spring 77 and opens valve 74 in gas inlet 75 which is supported by member 73. At the start of the firing stroke of drive piston 2, the opening in the projection 69 moves out of alignment with the end of tube 72 and the knob 78 on jet tank 28 moves forward out of the path of lever 76, but the pull of spring 77 on lever 76 is not strong enough to close valve 74 against damper 149, until the air pressure in the connected supply tanks of 92b to 951;, FIG. 5, have been reduced to atmospheric pressure. This erases previous pressures and allows selection of the desired gas supply pressure for the next stroke.

The return of the drive piston 2 to its initial position, ready for the next stroke is obtained by the light, compressed springs 84 that are prevented from springing out of line laterally by inclosures in

cylinders

85 and 86, cylinders 85 being attached to jet tank 28 at one end and with a sliding fit of the other end in cylinders 86 which are secured to the cylinder 1 and

plates

12 and 12a.

FIGS. 1b and 2b show the drive piston 2 brought to rest at the end of its stroke. The air 147a between the drive piston 2 and the tool piston 3 was compressed to a very small volume at high pressure and with several hundreds of degrees rise in temperature. This pressure has accelerated the tool piston 3 and the air 147a has expanded to roughly its former volume; in the impact drive piston 2 has been brought to rest and the tool piston 3 (same mass as the drive piston 2) has acquired the velocity of drive piston 2 before impact, and will be brought to rest in the work before it severely bumps the end of cylinder 1. The operator adjusts his thrust by a cocking device, explained later, under FIG. 5, so that the tool does not pass entirely through the work, or bury itself as far as lugs 19. If the operator misjudges the power of the tool, and the tool 16 passes entirely through the work, then the residual kinetic energy of the tool piston 3 will be expended in burying lugs 19 in the work and/or compressing spring 10 and pulling the end of cylinder 1 toward the work. The lug 19 and tool cylinder 3 are of high strength alloy steel, or a larger dimension of aluminum alloy, in order to withstand such an accidental shock against the work.

FIG. 5 is a schematic, elevation view of the basic hammer with a pick tool 16 screwed into the end of the tool piston 3 as in FIGS. 1a and 2a. A controlled gas supply is shown connected by light pressure hose 88 (such as plastic, impregnated fiber glass). The pick tool is being used to break up a concrete layer 87 on a sand substrate 87a. A light pressure hose 89 connects from the gas outlet 90 on inlet 75 to the cooling water tank 23 filled at screw cap 148. The hose 88 is a direct extension of inlet 75 and connects to the manifold 91 and through valves 92a, 93a, 94a, and 95a respectively to air cylinders 92b, 93b, 94b, and 95b, connected to

valves

92c, 93c, 94c, and 95c which connect in parallel to manifold 96 and hence to air storage tank 97. Valve pairs, 92a92c, 93a- 930, 94a94c, and 95a95c, are ganged together by

piston rods

92d, 93d, 94d, and 950., such that a valve with an a subscript of a given pair is closed when the valve with the c subscript is open, and vice versa. The valves of each pair also have snap toggle action that tends to keep them in a given closed or open position until acted on by an external control force. The valves are actuated by lever arms 98 upon which slide up and down small knobs 99 that are forced outward by springs 100 to follow cam surfaces 101. Small knobs 99 are connected by pivots 102 to

rotatable levers

150 and 151 which are driven by piston rods 9211 to 95d which slide pistons 103 in cylinders 104. Cylinders 104 are connected to air cylinders 92b, 93b, 94b, and 9512, by openings 105. When the lever arms 98 of the ganged valves 92a92c, through 95a-95c, are rotated to the left hand side the corresponding pistons 103 receive air pressure through the openings 105 to maintain the given ganged valves in the left hand position until the air in the corresponding air supply cylinders 92b to 95b with valves in the left hand position has been reduced in pressure at the beginning of the stroke of drive piston 2, by leaking out through the bottom of tube '72, FIG. la, which has been uncovered by the tank projec tion 69 before the spring 77 can shut valve 74. Damper 149 assures that the valve 74 closes sufficiently slowly. After the stroke of the tool piston 3, all gang valves 92a92c, 93a-93c, 94a94c, and 95a-9Sc, are returned to the right hand side position by the springs 106 in hydraulic control cylinders 107 pulling to the right the pistons 108 and piston rods 92d to 95d. This closes the valves on the left hand side and opens those on the right hand side to refill air tank cylinders 92b to 951;. Those pistons 108 that are then pushed to the left by the fiuid from manifold 109 cause corresponding pairs of toggletype, gang valves to close on the right side and open on the left side to supply air to the jet tank 28. The fluid flow to activate pistons 108 comes by way of manifold 109, and pressure hose 110 from cocking cylinder 117 I supported by the member 113 to the fin 13 and cylinder 1. Plunger 114 may be pressed against the work through different distances to drive piston 115 the proper amount to activate from 1 to 4 of the gang valve pairs 92a-92c, to 95a-95c. The four springs 106 increase in strength in successive lower cylinders 107, so that the ganged valves are activated in sequence as plunger 114 is pressed against the work to four different positions. The operator listens to the click of the gang, toggle-type valves as from 1 to 4 to obtain the desired impulse against the work for each stroke. The plunger 114 can then be removed from the work to the proper distance for the tool to reach maximum velocity before impacting the work, without affecting the position of the gang, toggle-type valves until after the drive piston 2 has started its stroke; then with the required pressure in the jet tank 28, the air is held in by check valve 70 until it expands through nozzle 30, and the end of tube 72 is uncovered by jet tank projection 69, and damper 149 prevents the rapid closing of valve 74 until the air in the cylinders 92b to 95b in the on position and the connected cylinders 104 leaks out through the end of tube 72. The springs 106 are strong enough to pull any gang valves 92a-92c through 95a95c in the left hand on position to the right or off position, the valves 92a to 95a then being shut and the valves 92c to 95c open, in readiness for the next cocking operation by plunger 114.

The holding handle 46 is held by supports 86a to the frame 14. The thumb, control trigger 45 is pivoted at 116 and connected to the end 117 of wire 118 that passes around pulley 119 and then by conduit protected path 59 to trigger 58 of FIG. 2b.

FIG. 6a shows the central cross-section of tool 120 for driving posts or piling that can be replaceably screwed into the end of tool piston 3.

FIG. 6b indicates the use of the tool 120 in FIG. 6a; a metal cap 121 is placed on top of the post 122 to protect it from direct contact with the tool 120 as the post is driven into earth 123, shown in cross-section.

FIG. 7a indicates the central cross-section of the grubbing tool 124 replaceably screwed into the end of tool piston 3.

FIG. 7b illustrates the application of grubbing tool 124 to chisel a large chip 125 from tree tap root 126 of stump 127 in a position where it is not necessary to cut out sections of surrounding

roots

128 and 129 in order to cut the tap root 126, but where there is not enough room to work as shown with a bandsaw.

FIG. 8a shows the tool 130 for driving nails 131, replaceably screwed into tool drive piston 3. The nail 131 is held against the steel insert cylinder 133 by magnetic forces-as discussed later-a given insert cylinder 133 having either a fiat bottom or a lip to position the nail as desired, and may be quickly removed by extending the bent end of a wire tool up hollow 134 and into recess 135 and pulling outward. The upper plate 136 of the cylindrical tool 130 is of steel to conduct magnetic flux and has as an integral part the downward projecting cylinder 137, and makes a screw fit into aluminum alloy cylinder 138 which has a screw-on bottom plate 139 of aluminum alloy. Insertable, permanent, cylindrical magnet 140 is secured between the two

end plates

136 and 139 with rubber packing plate 141 to prevent excessive jarring of permanent magnet 140, and plastic cylinder 142 to cause the magnet return flux 143 to fiow down through the insert 133 and nail 131 to provide sufiicient magnetic force of attraction between insert 133 and nail 131 to hold the nail in the required position while being driven. The

work

144 and 145 is placed ready for nailing and the nail 131 is separated from the work 144 enough for it to gain maximum velocity, by impact of tool piston 3 from drive piston 2, before impact on the work. For work that requires very careful spotting of nail 131, the initial separation of the nail from the work may be decreased by opening the vent 21, FIG. 2a, that is nearest the initial position of tool piston 3. Tool piston 3 is now propelled forward a shorter distance for expansion of the shorter column of air 147a, FIGS. 2a, 2b, now compressed on impact of drive piston 2 and tool piston 3.

FIG. 8b shows the nail 131 driven into a cross-section of the

work

144 and 145 by the thrust of the tool 130. The Operator gauges the impulse of the blow required to drive a given nail by contact of the work with the cocking plunger 114, FIG. 5, so that the tool 130 will not sink appreciably in the work 144.

FIG. 80 shows the tool 130 retracted and the nailhead recess 132 formed by the cylindrical projecting lip 146 for holding a nail to be driven in the proper position. The nail 131 is countersunk in the work with a narrow, open ring 146 where the lip 146 sank into the work. This open ring 146' can be made very narrow if so desired, as the only function of 146 assists in accurate spotting of the nail 131 on tool 130.

It is claimed and desired to secure by Letters Patent:

1. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, hammerhead means for transmitting and withstanding said force impulse produced by impact deceleration of said hammerhead means ensemble at the end of its stroke, a jet-supply gas tank, a gas exhaust nozzle connected by duct means to said tank and pointed in the opposite direction to the stroke of said 1 hammerhead means ensemble for the formation of an exhaust gas jet whose reaction force accelerates said ensemble in its forward stroke while an equal and opposite force drives said jet in the rearward direction without recoil forces acting in the rearward direction on any part of said hand tool except for possible secondary elfects as by small deflections of said jet by parts of said hand tool, jet valve means in series with said nozzle for initiating the fiow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means for supplying power for a part of the operational cycle of said jet valve means, cam-type means for opening a fillvalve supported by a stationary complex of said hand tool, consisting of mutually attached stationary parts including a frame, a check valve in series with said jet-supply tank, attachment means to form a unit of the members of said hammerhead means ensemble, and completing said ensemble, a first guide means for interaction with a second guide means on said stationary parts complex of said hand tool for the stroke of said hammerhead means ensemble, said stationary parts complex of said hand tool, and said second guide means supported by said stationary parts complex of said hand tool for a freely moving, nonrotating stroke of said hammerhead means ensemble, second force means supported from said stationary parts complex for returning said hammerhead means ensemble to its prestroke position, and a third force means supported from said stationary parts complex for interaction with said first force means, and a trigger locking and release means for maintenance of the closed position of said slide valve means in the retracted position of said hammerhead means ensemble, and said trigger locking and release means actuated by manual means for control of said third force means for opening of said jet valve means for the forward stroke of said hammerhead means ensemble, and a jet-supply tank filling-means actuated in the retracted stroke position of said tank, consisting of a filling-inlet on said jet-supply tank, a gas supply outlet means mounted on said stationary parts complex, and aligned and making contact with said filling-inlet, a fillvalve in series with said gas supply outlet, a fourth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means of said hammerhead means ensemble to open said fillvalve in the retracted position of said hammerhead means ensemble, and said check valve means in series with the inlet of said jet-supply tank and carried as a part of said hammerhead means ensemble.

2. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, hammerhead means to transmit and withstand said force impulse produced by impact deceleration of said ensemble at the end of its stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the stroke of said ensemble, for formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke, while an equal and opposite force drives said jet in the rearward direction without recoil forces acting on any part of said hand tool in the rearward direction except for small secondary effects from small deflections of said jet by hand tool parts, jet valve means in series with said jet consisting of, a slide valve cutting across the throat of said nozzle, a nozzle entrance contained in a wall in sliding contact with a first side of said slide valve, a nozzle mouth contained in a pressure plate in sliding contact with a second side of said slide valve, stops on said hammerhead means ensemble to keep said nozzle entrance and said nozzle mouth aligned, an aperture in said slide valve aligned with said nozzle entrance and said nozzle mouth for the open position of said jet slide valve, and first force means mounted on said hammerhead means ensemble to firmly press together the slidable surfaces of said pressure plate, said slide valve, and said wall containing said nozzle entrance, for prevention of leakage, so that said slide valve initiates the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, second force means to bias said jet valve means to the open position, camtype means to open a fill-valve supported by a stationary parts complex of said hand tool, a check valve in series with said jet-supply tank, attachment means to form a unit of the members of said hammerhead means ensemble, and the last member of said ensemble, first guide means for interaction with second guide means on said stationary parts complex for the forward stroke of said hammerhead means ensemble, a stationary parts complex of said hand tool, consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex for a freely moving, non-rotating stroke of said hammerhead means ensemble, third force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, ramp-type means mounted on said stationary parts complex for closing said slide valve on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex to lock said ramp-type means in the valve-closing-position before the return stroke of said hammerhead means ensemble and until activated by manual control for the start of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means by said second force means, fourth force means mounted on said stationary parts complex to return said ramptype means to its position prior to the forward stroke of said hammerhead means ensemble, after removal of contact with said jet-valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted stroke position of said tank, consisting of, a filling-inlet on said jet-supply tank, a gas supply outlet means mounted on said stationary parts complex and aligned and making contact with said filling-inlet, a fill-valve in series with said gas supply outlet means, fifth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means mounted on said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means in series with the inlet of said jet-supply tank and carried as part of said hammerhead means ensemble.

3. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, a drive piston to compress a gas column at the end of said stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the forward stroke of said hammerhead means ensemble, for the formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke while an equal and opposite force drives said jet in the rearward direction without recoil forces in the rearward direction acting on any part of said hand tool except for small secondary effects by small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means for supplying power for part of the operational cycle of said jet valve means, cam-type means for opening a fill-valve supported by a stationary parts complex of said hand tool, a checkvalve in series with said jet-supply tank, attachment means to form a unit of the members of said ensemble, and completing said hammerhead means ensemble, first guide means for interaction with said second guide means on said stationary parts complex for the stroke of said hammerhead means ensemble, said stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex for a freely moving, nonrotating stroke of said hammerhead means ensemble, a cylinder supported by said stationary parts complex, whose first end receives said drive piston in freely sliding contact, a tool mounting piston received by the second end of said cylinder, a tool mounted on said tool mounting piston, a gas column between said drive and tool mounting pistons, and a mass of said tool mounting piston including said tool, substantially equal to the mass of said drive piston and the other parts of said hammerhead means ensemble, so that when said drive piston is decelerated by the compressive force it exerts on said gas column, said tool mounting piston is accelerated by the same compressive force, for the same time, to approximately the velocity of said drive piston at the termination of the thrust of said jet, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, third force means supported from said stationary parts complex to return said tool mounting piston to its prestroke position, and a fourth force means supported from said stationary parts complex for interaction with said first force means and a trigger locking and release means, for maintenance of the closed position of said slide valve means in the retracted position of said hammerhead means ensemble, and said trigger and release means actuated by manual means for control of said fourth force means for opening said slide valve for the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted stroke position of said jet-supply tank, consisting of a filling inlet on said jet-supply tank, a gas supply outlet means mounted on said stationary parts complex and aligned and making contact with said filling inlet, a fillvalve in series with said gas supply outlet, fifth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means mounted on said hammerhead means ensemble to open said fill-valve in the retracted position of said hammerhead means ensemble, and said checkvalve means in series with the inlet of said jet-supply tank and carried by said hammerhead means ensemble.

4. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, a drive piston to compress a gas column at the end of said stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the forward stroke of said hammerhead means ensemble, for the formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke while an equal and opposite force drives said jet rearward, without recoil forces in the rearward direction acting on any part of said hand tool except for possible secondary effects by small deflections of said jet by parts of said hand tool, jet valve means in series with said jet for initiation of the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means to bias said jet valve means to the open position, cam-type means for opening a fill-valve supported by a stationary parts complex, a check valve in series with said jet-supply gas tank, attachment means to form a unit of the members of said hammerhead means ensemble, and completing the members of said hammerhead means ensemble, first guide means for interaction with second guide means on said stationary parts complex, a stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex for a freely moving, nonrotating stroke of said hammerhead means ensemble, a cylinder supported by said stationary parts complex that receives said drive piston in freely sliding contact at a first end, a tool mounting piston received by the second end of said cylinder, a tool mounted on said tool mounting piston, a gas column between said drive and tool mounting pistons, and a mass of said tool mounting piston including that of said tool mounted thereon, substantially equal to the mass of said hammerhead means ensemble, so that when said hammerhead means ensemble is decelerated by the compressive force it exerts on said gas column, said tool mounting piston is accelerated by the same compressive force, for the same time, to approximately the velocity of said hammerhead means ensemble at the ter mination of the thrust of said jet, port means in said cylinder, opening and closing means for said port means, a first open port being positioned a first distance from said tool mounting piston in its retracted position, said first distance being approximate effective length of said gas column between said pistons before appreciable compression starts in the forward stroke of said hammerhead means ensemble, said drive piston brought to rest by the compression of said gas column at a second distance past said open port, said second distance being determined by said first distance, and an effective stroke length of said tool mounting piston, defined by a third distance through which it must be accelerated by the pressure of said gas column before it attains the approximate velocity of said drive piston at said first open port, said third distance being equal to said second distance and hence determined by said first distance between said first open port and the retracted position of said tool mounting piston, which distance may be selected by choice of said open port at a desired position, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, third force means supported from said stationary parts complex to return said tool mounting piston to its prestroke position, ramp-type means mounted on said stationary parts complex for closing said jet-valve means on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex for locking said ramp-type means in its jet valve-closing-position before the return stroke of said hammerhead means ensemble and until, actuated by manual control for the start of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means of said hammerhead means ensemble by said first force means, fourth force means to return said ramp-type means to its prestroke position after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted position of said hammerhead means ensemble, consisting of a filling-inlet on said jet-supply tank, gas supply outlet means mounted on said stationary parts complex. and aligned with and contacting said filling-inlet, a fill-valve in series with said gas supply outlet means, fifth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said camtype means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and check-valve means of said hammerhead means ensemble in series with said fillinginlet of said jet-supply tank.

5. In a hand tool, the combination of, a hammerhead means ensemble for the delivery of a force impulse at the end of its stroke, consisting of, hammerhead means to transmit and withstand said force impulse, a jet-supply gas tank, a gas exhaust nozzle ducted to said tank and pointed in the opposite direction to the forward stroke of said hammerhead means ensemble, for the formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke while an equal and opposite force drives said jet in the rearward direction, without recoil forces acting in the rearward direction on any part of said hand tool except due to possible secondary effects due to small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means to bias said jet valve means to.

the open position, cam-type means for opening a fill-valve supported by a stationary parts complex of said hand tool, a check-valve in series with said jet-supply tank, attachment means to form a single unit of the members of said hammerhead means ensemble, and completion of said hammerhead means ensemble by first guide means for interaction with second guide means on said stationary parts complex for the stroke of said hammerhead means ensemble, a stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex for a freely moving, nonrotating stroke of said hammerhead means ensemble, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, ramp-type means supported from said stationary parts complex for closing said jet valve means on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex to lock said ramp-type means in its jet valve-closing position before the return stroke of said hammerhead means ensemble and until actuated by manual control for the start of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means by said first force means, third force means mounted on said stationary parts complex for returning said ramp-type means to its position prior to the forward stroke of said hammerhead means ensemble, after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted stroke position of said jet-supply tank, consisting of, a filling-inlet on said jet-supply tank, a ground flange with a sliding contact surface around said fillinginlet, a gas supply outlet tube aligned with said filling-inlet in the retracted position of said tank, a ground flange surface slidable on the end of said gas supply outlet tube and slidable over the surface of said ground flange around said jet-supply tank filling-inlet, fourth force means for pressing said slidable flange on said gas supply outlet tube against said flange around said jet-supply tank filling-inlet to prevent gas leakage, a fill-valve in series with said gas supply outlet, fifth force means mounted on said stationary parts complex to bias said fill-valve to the closed position ,said cam-type means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means of said hammerhead means ensemble in series with said jet-supply tank filling-inlet.

6. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, a drive piston to compress a gas column at the end of said stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the forward stroke of said hammerhead means ensemble, for formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke while an equal and opposite force drives said jet in the rearward direction, without recoil forces acting in the rearward direction on any part of said hand tool except for possible secondary effects by small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate its flow when opened for the forward stroke of said hammerhead means ensemble, first force means to bias said jet valve to the open position, cam-type means for opening a fill-valve supported by a stationary parts complex of said hand tool, a check valve in series with said jet-supply tank, attachment means for forming a unit of the members of said hammerhead means ensemble, and first guide means completing the members of said hammerhead means ensemble for interaction with second guide means on said stationary parts complex for the stroke of said hammerhead means ensemble, said stationary parts complex, of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex of said hand tool for a freely moving, nonrotating stroke of said hammerhead means ensemble, a cylinder supported by said stationary parts complex that receives said drive piston in freely sliding contact at a first end, a tool mounting piston received by the second end of said cylinder, a tool mounted on said tool mounting piston, a gas column between said drive and tool mounting pistons, and a mass of said tool mounting piston including said tool, substantially equal to the mass of said hammerhead means ensemble, so that when said hammerhead means ensemble is decelerated by the compressive force it exerts on said gas column, said tool mounting piston is accelerated by the same compressive force, for the same time, to approximately the velocity of said hammerhead means ensemble at the termination of the thrust of said jet, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, third force means supported from said stationary parts complex for returning said tool mounting piston to its prestroke position, ramp-type means mounted on said stationary parts complex to close said jet valve means on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex for locking said ramp-type means in its jet valve-closing position before the return stroke of said hammerhead means ensemble and until actuated by manual control for initiation of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means on said hammerhead means ensemble by said first force means, fourth force means to return said ramp-type means to its position prior to the forward stroke of said hammerhead means ensemble after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling-means actuated in the retracted stroke position of said tank, consisting of, a filling-inlet on said jet-supply tank, a first ground flange with a sealing, slide-contact surface around said filling inlet, a gas supply outlet tube mounted on said stationary parts complex and aligned with said fillinginlet in the retracted stroke position of said tank, a second ground flange surface, axially slidable on the end of said gas supply outlet tube and slidable across the surface of said first ground flange around said tank filling-inlet, fifth force means to press said first and second flanges together to prevent gas leakage, a fill-valve in series with said gas supply outlet tube and carried by said stationary parts complex, sixth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means of said hammerhead means ensemble-in series with said tank filling-inlet.

7. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, hammerhead means to transmit and withstand said force impulse produced by impact deceleration of said hammerhead means ensemble at the end of its stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the stroke of said hammerhead means ensemble, for formation of an exhaust gas jet whose reaction force accelerates said ensemble in its forward stroke while an equal and opposite force drives said jet in the rearward direction without recoil forces in the rearward direction acting on any part of said hand tool except for small secondary effects by possible small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means to bias said jet valve means to the open position, cam-type means for opening a fill-valve supported by a stationary parts complex of said hand tool, a check valve in series with said jet-supply tank, attachment means to form a single unit of the members of said hammerhead means ensemble, and first guide means completing the members of said hammerhead means ensemble, for interaction with second guide means on said stationary parts complex for the stroke of said hammerhead means ensemble, said stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and second guide means supported from said stationary parts complex for a freely moving, nonrotating stroke of said hammerhead means ensemble, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its retracted position, ramp-type means mounted on said stationary parts complex to close said jet valve means on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex for locking said ramp-type means in its jet valve-closing position until actuated by manual control for initation of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the consequent opening of said jet valve means by said first force means, third force means mounted on said stationary parts complex to return said ramp-type means to its position prior to the forward stroke of said hammerhead means ensemble, after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means, actuated in the retracted stroke position of said tank, consisting of, a filling-inlet on said jet-supply tank, gas supply outlet means mounted on said stationary parts complex and aligned and making contact with said filling-inlet, a fill-valve in series with said gas supply outlet supported by said stationary parts complex, fourth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means mounted on said hammerhead means ensemble to open said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve in series with said filling-inlet of said jetsupply tank and carried by said hammerhead means ensemble, and a cocking means mounted on said stationary parts complex, consisting of, a cocking plunger, a piston driven by one end of said plunger, 21 cocking cylinder that receives said piston, hydraulic fluid displaced from said cylinder as determined by the distance of said hand tool from the work for the tip of said plunger contacting said work, a hydraulic fluid manifold to receive fluid displacements received by said cocking plunger, a first valvecontrol-set of cylinders, duct connected to said hydraulic fluid manifold, a first set of pistons sliding in said first set of cylinders, piston rods attached to said first set of pistons and displaced toward the cocking position by the flow of said hydraulic fluid into said first valve-controlset of cylinders, fifth force means supported from said stationary parts complex for retraction of said first set of pistons to the precocked position with displacement of said hydraulic fluid back into said manifold, said fifth force means being stepped in magnitude so that increased volume of hydraulic fluid displacement caused by change in said plunger position drives said first set of pistons outward in said cocking position in succession, by successive flows of said hydraulic fluid into said first set of control cylinders, ganged toggle-type pairs of valves actuated by said piston rods, the connections between the moving parts of said ganged pairs of toggle-type valves and said piston rods being so phase positioned that one of a pair is open when the other is closed, and vice versa, a set of gas tank cylinders with each tank of the set connected at a first end to the first of a said pair of ganged toggle-type valves, and connected at the second end to the second of a said pair of toggle-type valves, a gas supply manifold connected to a first end of a said gas tank cylinder by the first of a pair of said pairs of toggletype valves, and a gas supply manifold to said gas supply outlet means and hence to said jet-supply gas tank inlet, connected to the second end of a said gas tank cylinder by the second of a said pair of toggle-type valves, and a precocked position of said ganged pairs of toggle-type valves in which the outlets, second ends, of said tank cylinders are closed by the second of a said pair of ganged toggle-type valves, and the inlets, first ends, are open, in the position of the first valves of said pairs of ganged valves for filling with compressed gas, and a cocked position of said ganged pairs of toggle-type valves in which the inlets, first ends, of said gas tank cylinders are closed by the first valves of said pairs of ganged toggle-type valves, and the outlets, second ends, of said gas tank cylinders to said gas supply outlet means and hence to said jet-supply tank are in the open position of the second valves of said pairs of ganged toggle-type valves, and a second valve-control set of cylinders through which said piston rods slide, a second set of pistons, in said set of second valve-control cylinders positioned by said piston rods, openings between each of said second set of control cylinders and one of said gas tank cylinders so placed with respect to the size and position of said second set of pistons that the only second set piston position when said openings supply gas pressure to hold said second set pistons in position is for said cocked position of a said ganged toggle-type pair of valves, the second valve of a said pair being then open to supply compressed gas to said jet-supply gas tank, and said second piston being then locked in place by gas pressure through a said opening from one of said gas tank cylinders regardless of the removal ofiaid plunger from said work, until the pressure in said gas tank cylinder has been vented toward atmospheric pressure by the forward stroke of said hammerhead means ensemble with temporary opening to the atmosphere of said gas supply outlet means, said fifth force means to return said ganged pairs of toggle-type valves to the precocked position after said venting of the cylinder tanks in the cocked position, so that said cocking plunger must be displaced to cause one or more of said pairs of ganged toggle-type valves to be moved to the cocked position before said jet-supply tank can be filled with compressed gas, and the magnitude of each impulse of said hammerhead means ensemble being determined by the number of said ganged toggle-type pairs of valves that are actuated to the cocked position by the different distances said cocking plunger, tip in contact with work, is driven into said cocking cylinder by operator positioning of said hand tool with respect to the work.

8. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of a drive piston to compress a gas column at the end of said stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the forward stroke of said hammerhead means ensemble, for formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke, while an equal and opposite force drives said jet in the rearward direction, without recoil forces in the rearward direction acting on any part of said hand tool, except for possible secondary effects by small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first force means to bias said jet valve means to the open position, cam-type means for opening a tank fill-valve which is supported by a stationary parts complex of said hand tool, a check valve in series with said jet-supply tank, attachment means to form a single unit of said hammerhead means ensemble, and a first guide means, the last member of said hammerhead means ensemble, for interaction with second guide means supported by said stationary parts complex for the stroke of said hammerhead means ensemble, said stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported from said stationary parts complex, for a freely moving, nonrotating stroke of said hammerhead means ensemble, a cylinder supported by said stationary parts complex that receives a drive piston in freely sliding contact at a first end, a tool mounting piston received by the second end of said cylinder, a gas column between said drive and tool mounting pistons, and a mass of said tool mounting piston including said tool, substantially equal to the mass of said hammerhead means ensemble, so that when said hammerhead means ensemble is decelerated by the compressive force its drive piston exerts on said gas column, said tool mounting piston is accelerated by the same compressive force, for the same time, to approximately the velocity of said drive piston at the termination of the thrust of said jetfor relatively small return stroke force means on said pistons, second force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, third force means supported from said stationary parts complex for return of said tool mounting piston to its prestroke position, ramp-type means mounted on said stationary parts complex to close said jet valve means on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex for locking said ramp-type means in its jet valve-closing position before the return stroke of said hammerhead means ensemble and until actuated by manual control for initiation of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means on said hammerhead means ensemble by said first force means, fourth force means mounted on said stationary parts complex to return said ramp-type means to its position prior to the forward stroke of said hammerhead means ensemble, after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and a jet-supply tank filling means actuated in the retracted stroke position of said hammerhead means ensemble, consisting of, a filling-inlet on said jet-supply tank, a gas supply outlet means mounted on said stationary parts complex and aligned with and contacting said jet-supply tank filling-inlet, a fill-valve in series with said gas supply outlet means, and supported by said stationary parts complex, fifth force means to bias said fillvalve to the closed position mounted on said stationary parts complex, said cam-type means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means of said hammerhead means ensemble in series with said filling-inlet of said jet-supply tank, and a cocking means mounted on said stationary parts complex, consisting of, a cocking plunger, a piston displaced by one end of said plunger, a cocking cylinder that receives said piston, hydraulic fluid displaced from said cocking cylinder by amounts depending on the displacement of said plunger with one end against the work and said hand tool positioned at different distances from the work, a hydraulic fluid manifold ducted to said cocking cylinder to receive the hydraulic fluid displacements produced by said cocking plunger, a first set of control cylinders duct connected to said hydraulic fluid manifold, a first set of pistons sliding in-said first set of cylinders, piston rods attached to said first set of pistons displaced toward the cocking position by the flow of said hydraulic fluid into said first set of valve-control cylinders, sixth force means to retract the position of said first set of pistons with displacement of said hydraulic fluid back into said manifold, said sixth force means being stepped in magnitude so that increased volume of fluid displacement caused by change in said cocking plunger position relative to said cocking cylinder, drives said first set of pistons outward in the cocking direction in succession, by successive flows of said hydraulic fluid into said first set of control cylinders, ganged toggle-type pairs of valves actuated by said piston rods, the connections between the moving parts of said ganged pairs of toggle-type valves ands-aid piston rods being so phase positioned that one of a pair is open when the other is closed and vice versa, a set of gas tank cylinders with each tank of the set con nected at a first end to the first of a said pair of toggletype valves, and connected at the second end to the second of a pair of toggle-type valves, a gas supply manifold connected to the first end of a gas tank cylinder by the first of a pair of said pairs of toggle-type valves, and a gas manifold to said gas supply outlet means, and hence to said jet-supply gas tank inlet, connected to the second ends of said gas tank cylinders by the second of a pair of said toggle-type valves, and a precocked position of said ganged pairs of toggle-type valves in which the outlets, second ends, of said tank cylinders are closed by the second valves of said ganged pairs of toggle-type valves, and the inlets, first ends, are opened by the first valves of said pairs of ganged toggle-type valves for filling with compressed gas from said gas supply manifold, and a cooked position of said ganged pairs of toggletype valves in which the inlets, first ends, of said tank cylinders are closed by the first valves of said pairs of ganged toggle-type valves, and the outlets, second ends, to said gas supply outlet means and hence to said jetsupply tank are opened by the second valves of said pairs of ganged toggle-type valves, and a second set of valve control cylinders through which said piston rods slide, second pistons in said second set of control cylinders positioned by said piston rods, openings between each of said second control cylinders and one of said gas tank cylinders so placed with respect to the size and position of said second set of pistons that the only position of said pistons of said second set, when said openings supply substantial gas pressure to hold said second pistons in position is for the cocking position when the second valves of said pairs of ganged toggle-type valves are open to supply compressed gas for said jetsupply tank, said second pistons then being locked in place by gas pressure from said openings between said gas tank cylinders and said second valve-control cylinders, regardless of the removal of said plunger from said work, until the pressure in said gas tank cylinders has been vented toward atmospheric pressure by the forward stroke of said hammerhead means ensemble with temporary opening to the atmosphere of said gas supply outlet means, said sixth force means to return said ganged pairs of toggle-type valves to the precocked position after said venting of the cocked cylinders to atmospheric pressure, so that said cocking plunger must move one or more of the ganged pairs of toggle-type valves to the cocked position before said jet-supply tank can be filled with compressed gas, and the magnitude of each impulse of said hammerhead means ensemble being determined by the number of said pairs of toggle-type valves that are actuated to the cocked position by the different distances said cocking plunger, in contact with the work at one end, is driven into said cocking cylinder by operative positioning of said hand tool.

9. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, a drive 'piston to compress a gas column at the end of said stroke, a jet-supply gas tank, a gas exhaust nozzle connected to said tank by duct means and pointed in the opposite direction to the forward stroke of said ensemble for formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke, while an equal and opposite foi'ce drives said jet in the opposite direction, with out recoil forces in the rearward direction acting on any part of said hand tool except for possible secondary effects produced by small deflections of said jet by parts of said hand tool, jet valve means in series with said jet to initiate flow of said jet when opened for the forward stroke of said hammerhead means ensemble, first [force means to bias said jet valve to the open position, camtype means for opening a tank filling-valve which is supported by a stationary parts complex of said hand tool fonmed by the mutual attachment of stationary parts including a frame, a check valve in series with said jetsupply tank, attachment means to form a single unit of the members of said hammerhead means ensemble, and a first guide means, a last member of said hammerhead means ensembel, for interaction with a second guide means on said stationary parts complex :for the stroke of said hammerhead means ensemble, a stationary parts complex, said second guide means supported by said stationary parts complex, a cylinder supported by said stationary parts complex that receives said drive piston in freely sliding contact at a first end, a tool mounting piston received in freely sliding contact by the second end of said cylinder, at gas column between said drive and tool mounting pistons, first interchangeable tool, mountingmeans on said tool mounting piston, interchangeable tools with second mounting means for interac tion with said first interchangeable tool, mounting means on said tool mounting piston, mass of said tool mounting piston including one of said interchangeable tools, substantially equal to the mass of said hammerhead means ensemble, so that when said hammerhead means ensemble is decelerated by the compressive force it exerts on said gas column, said tool mounting piston and its mounted tool are accelerated by the same compressive force, for the same time, to approximately the velocity of said drive piston at the termination of the thrust of said jetneglecting small return stroke forces on said pistons, second force means supported from said stationary parts complex to return said drive piston to its *prestroke position, third fonce means supported from said stationary parts complex for returning said tool mounting piston to its prestroke position, and the following three members supported from said stationary parts complex, ramp-type means to close said jet valve on the return stroke of said hammerhead means ensemble, trigger means for locking said ramp-type means in its jet valve-closing position until actuated by manual control for the start of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet valve means on said hammerhead means ensemble by said first force means, and fourth force means to return said ramp-ty.pe means to its position prior to the forward stroke of said hammerhead means ensemble after removal of contact with said jet valve means by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted stroke position of said hammerhead means ensemble, consisting of, a filling inlet means on said jet-supply tank, and three members supported by said stationary parts complex, a gas supply outlet means aligned with and contacting said jet-supply tank filling inlet means, a fill-valve in series with said gas supply outlet means, and fifth fonce means to bias said fill-valve to the closed position, said cam-type means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means of said hammerhead means ensemble in series with the inlet means of said jet-supply tank, and a cooling jacket for said cylinder at the position of compression of said gas column, consisting of, a jacket wall around the cooled length of said cylinder, an annular cavity formed by said wall and said cylinder, liquid-under-pressure-means surrounding said jacket Wall, small openings in said wall for the formation of liquid spray, liquid spray from said openings impinging against the wall of said cylinder to be cooled, and a vent in said annular cavity for the escape of gas generated by the impact of said spray on said cylinder.

10. In a hand tool, the combination of, a hammerhead means ensemble to deliver a force impulse at the end of its stroke, consisting of, hammerhead means to transmit and withstand said force impulse produced by impact deceleration of said ensemble at the end of its stroke, a jet-supply gas tank, a gas exhaust nozzle ducted to said tank and pointed in the opposite direction to the stroke of said hammerhead means ensemble for formation of an exhaust gas jet whose reaction force accelerates said hammerhead means ensemble in its forward stroke, while an equal and opposite force drives said jet in the rearward direction, without recoil forces in the rearward direction acting on any part of said hand tool except for possible secondary effects by small deflections of said jet by hand tool parts, jet valve means in series with said jet, to initiate the flow of said jet when opened for the forward stroke of said hammerhead means ensemble, consisting of, a jet slide valve that moves between the wall means of said jet-supply tank and a pressure plate, a nozzle entrance in said wall, a nozzle mouth in said pressure plate aligned with said nozzle entrance, stops on said hammerhead means ensemble to maintain alignment of said nozzle entrance and said nozzle mouth, first force means to firmly press said pressure plate, said jet slide valve, and said tank wall means together to prevent gas leakage, an aperture in said jet valve aligned with said nozzle entrance and said nozzle mouth in the open position of said jet slide valve, a piston rod attached to said jet slide valve, a piston mounted on said rod, a cylinder to receive said piston, a duct from said cylinder to said jet-supply gas tank to bias said slide valve to the open position as long as there is an appreciable gas pressure in said jet-supply gas tank, and second force means applied to said slide valve means for additional bias on said slide valve toward the open position when the gas pressure of said jet-supply tank becomes low due to the exhaust from said nozzle, such that the combined forces of the gas pressure on said piston and said secondary force means, open said slide valve rapidly when it is released by a ramp means mounted on a stationary parts complex of said hand tool, when triggered for the initiation of the forward stroke of said hammerhead means ensemble, so that the jet valve opening time with its inefficient jet thrust is only a small fraction of the total exhaust time, damping means reacting with the moving parts of said jet slide valve means to brake the velocity of said slide valve when approaching its open position, the component of the bias force on said jet slide valve due to the gas pressure from said jet-supply tank approaching zero as gas is discharged from said nozzle, with a marked reduction in the force that must be exerted by said ramp means to close said jet slide valve on the return stroke of said hammerhead means ensemble, and the additional parts of said hammerhead means ensemble, consisting of, cam-type means for opening a tank fill-valve which is supported by said stationary parts complex, a check valve in series with said jet-supply tank, attachment means to form a single unit of the members of said hammerhead means ensemble, and a last member of said hammerhead means ensemble, first guide means for interaction with second guide means on said stationary parts complex for the stroke of said hammerhead means ensemble, said stationary parts complex of said hand tool consisting of mutually attached stationary parts including a frame, and said second guide means supported by said stationary parts complex for a freely moving, nonrotating stroke of said hammerhead means ensemble, third force means supported from said stationary parts complex to return said hammerhead means ensemble to its prestroke position, ramp-type means mounted on said stationary parts complex for closing said jet slide valve on the return stroke of said hammerhead means ensemble, trigger means mounted on said stationary parts complex to lock said ramp-type means in its jet valve-closing position before the return stroke of said hammerhead means ensemble and until actuated by manual control for the start of the forward stroke of said hammerhead means ensemble with the release of said ramp-type means and the opening of said jet slide valve on said hammerhead means ensemble by the combined gas pressure on said piston and said second force means, fourth force means mounted on said stationary parts complex to return said ramp-type means to its position prior to the forward stroke of said hammerhead means ensemble, after removal of contact with said jet slide valve by the forward stroke of said hammerhead means ensemble, and jet-supply tank filling means actuated in the retracted position of said hammerhead means ensemble, consisting of, a filling inlet means on said jet supply-tank, a gas supply outlet means mounted on said stationary parts complex and aligned with and contacting said jet-supply gas tank filling inlet means, a fill-valve in series with said gas supply outlet means and mounted on said stationary parts complex, fifth force means mounted on said stationary parts complex to bias said fill-valve to the closed position, said cam-type means of said hammerhead means ensemble for opening said fill-valve in the retracted position of said hammerhead means ensemble, and said check valve means of said hammerhead means ensemble in series with said tank filling inlet means of said jet-supply gas tank.

References Cited by the Examiner UNITED STATES PATENTS 1,467,262 9/1923 Barker 91-469 X 1,621,382 3/1927 Stevens 6062 X 2,053,716 9/1936 Huck 91469 X 2,115,921 5/1938 Steiner 6062X 2,198,514 4/1940 Rippl 91355 2,374,019 4/ 1945 Kahler et a1. 91469 X 2,995,113 8/1961 Steiner 6054.5 X 3,010,430 11/1961 Allen et al. 91-469 X EDGAR W. GEOGHEGAN, Primary Examiner. ROBERT R. BUNEVICH, Examiner. SAMUEL LEVINE, Assistant Examiner.

Claims

3. IN A HAND TOOL, THE COMBINATION OF, A HAMMERHEAD MEANS ENSEMBLE TO DELIVER A FORCE IMPULSE AT THE END OF ITS STROKE, CONSISTING OF, A DRIVE PISTON TO COMPRESS A GAS COLUMN AT THE END OF SAID STROKE, A JET-SUPPLY GAS TANK, A GAS EXHAUST NOZZLE CONNECTED TO SAID TANK BY DUCT MEANS AND POINTED IN THE OPPOSITE DIRECTION TO THE FORWARD STROKE OF SAID HAMMERHEAD MEANS ENSEMBLE, FOR THE FORMATION OF AN EXHAUST GAS JET WHOSE REACTION FORCE ACCELERATED SAID HAMMERHEAD MEANS ENSEMBLE IN ITS FORWARD STROKE WHILE AN EQUAL AND OPPOSITE FORCE DRIVES SAID JET IN THE REARWARD DIRECTION WITHOUT RECOIL FORCES IN THE REARWARD DIRECTION ACTING ON ANY PART OF SAID HAND TOOL EXCEPT FOR SMALL SECONDARY EFFECTS BY SMALL DEFLECTIONS OF SAID JET BY PARTS OF SAID HAND TOOL, JET VALVE MEANS IN SERIES WITH SAID JET TO INITIATE THE FLOW OF SAID JET WHEN OPENED FOR THE FORWARD STROKE OF SAID HAMMERHEAD MEANS ENSEMBLE, FIRST FORCE MEANS FOR SUPPLYING POWER FOR PART OF THE OPERATIONAL CYCLE OF SAID JET VALVE MEANS, CAM-TYPE MEANS FOR OPENING A FILL-VALVE SUPPORTED BY A STATIONARY PARTS COMPLEX OF SAID HAND TOOL, A CHECKVALVE IN SERIES WITH JET-SUPPLY TANK, ATTACHMENT MEANS TO FORM A UNIT OF THE MEMBERS OF SAID ENSEMBLE, AND COMPLETING SAID HAMMERHEAD MEANS ENSEMBLE, FIRST GUIDE MEANS FOR INTERACTTION WITH SAID SECOND GUIDE MEANS ON SAID STATIONARY PARTS COMPLEX FOR THE STROKE OF SAID HAMMERHEAD MEANS ENSEMBLE, SAID STATIONARY PARTS COMPLEX OF SAID HAND TOOL CONSISTING OF MUTUALLY ATTACHED STATIONARY PARTS INCLUDING A FRAME, AND SAID SECOND GUIDE MEANS SUPPORTED BY SAID STATIONARY PARTS COMPLEX FOR A FREELY MOVING, NONROTATING STROKE OF SAID HAMMERHEAD MEANS ENSEMBLE, A CYLINDER SUPPORTED BY SAID STATIONARY PARTS COMPLEX, WHOSE FIRST END RECEIVES SAID DRIVE PISTON IN FREELY SLIDING CONTACT, A TOOL MOUNTING PISTON RECEIVED BY THE SECOND END OF SAID CYLINDER, A TOOL MOUNTED ON SAID TOOL MOUNTING PISTON, A GAS COLUMN BETWEEN SAID DRIVE AND TOOL MOUNTING PISTONS, AND A MASS OF SAID TOOL MOUNTING PISTON INCLUDING SAID TOOL, SUBSTANTIALLY EQUAL TO THE MASS OF SAID DRIVE PISTON AND THE OTHER PARTS OF SAID HAMMERHEAD MEANS ENSEMBLE, SO THAT WHEN SAID DRIVE PISTON IS DECELERATED BY THE COMPRESSIVE FORCE IT EXERTS ON SAID GAS COLUMN, SAID TOOL MOUNTING PISTON IS ACCELERATED BY THE SAME COMPRESSIVE FORCE, FOR THE SAME TIME, TO APPROXIMATELY THE VELOCITY OF SAID DRIVE PISTON AT THE TERMINATION OF THE THRUST OF SAID JET, SECOND FORCE MEANS SUPPORTED FROM SAID STATIONARY PARTS COMPLEX TO RETURN SAID HAMMERHEAD MEANS ENSEMBLE TO ITS PRESTROKE POSITION, THIRD FORCE MEANS SUPPORTED FROM SAID STATIONARY PARTS COMPLEX TO RETURN SAID TOOL MOUNTING PISTON TO ITS PRESTROKE POSITION, AND A FOURTH FORCE MEANS SUPPORTED FROM SAID STATIONARY PARTS COMPLEX FOR INTERACTION WITH SAID FIRST FORCE MEANS AND A TIGGER LOCKING AND RELEASE MEANS, FOR MAINTENANCE OF THE CLOSED POSITION OF SAID SLIDE VALVE MEANS IN THE RETRACTED POSITION OF SAID HAMMERHEAD MEANS ENSEMBLE, AND SAID TRIGGER AND RELEASE MEANS ACTUATED BY MANUAL MEANS FOR CONTROL OF SAID FOURTH FORCE MEANS FOR OPENING SAID SLIDE VALVE FOR THE FORWARD STROKE OF SAID HAMMERHEAD MEANS ENSEMBLE AND JET-SUPPLY TANK FILLING MEANS ACTUATED IN THE RETRACTED STROKE POSITION OF SAID JET-SUPPLY TANK, CONSISTING OF A FILLING INLET ON SAID JET-SUPPLY TANK, A GAS SUPPLY OUTLET MEANS MOUNTED ON SAID STATIONARY PARTS COMPLEX AND ALIGNED AND MAKING CONTACT WITH SAID FILLING INLET, A FILLVALVE IN SERIES WITH SAID GAS SUPPLY OUTLET, FIFTH FORCE MEANS MOUNTED ON SAID STATIONARY PARTS COMPLEX TO BIAS SAID FILL-VALVE TO THE CLOSED POSITION, SAID CAM-TYPE MEANS MOUNTED ON SAID HAMMERHEAD MEANS ENSEMBLE TO OPEN SAID FILL-VALVE IN THE RETRACTED POSITION OF SAID HAMMERHEAD MEANS ENSEMBLE, AND SAID CHECKVALVE MEANS IN SERIES WITH THE INLET OF SAID JET-SUPPLY TANK AND CARRIED BY SAID HAMMERHEAD MEANS ENSEMBLE.