Impulse-reaction propulsion cycle for mole

Claim 2

A linear impacting unit for a subsoil penetrator, comprising: a forward anvil fixed with respect to the penetrator nose, said anvil defining the forward end of a cavity; a hammer mounted in said cavity for impacting with said anvil; means for maintaining a continuous forward bias on said hammer; a source of hydraulic energy; and means responsive to hammer impact for applying said energy to said hammer against said bias for a defined distance of hammer return travel.

Claim 3

Propulsion apparatus for a subsoil mole, comprising: an elongated axial cavity in said device bounded by forward and rear anvils and containing an axially shuttling hammer; means for biasing said hammer continuously toward said forward anvil with a substantially constant first force; and means for accelerating said hammer away from said first anvil on contact therewith with a second force substantially greater than said first force, the energy imparted to said hammer by said second force being controlled to limit hammer rearward travel to a point short of said second anvil.

Claim 4

Propulsion apparatus for a subsoil mole, comprising: an elongated axial cavity in said device bounded by forward and rear anvils and containing an axially shuttling hammer; means for biasing said hammer continuously toward said forward anvil with a substantially constant first force; and means for accelerating said hammer away from said first anvil on contact therewith with a second force substantially greater than said first force, the energy imparted to said hammer by said second force being controlled to limit hammer rearward travel to a point short of said second anvil.

Claim 5

Apparatus pursuant to claim 2, wherein said biasing means and said accelerating means are both hydraulic and operated from the same pressure source.

Claim 6

Propulsion apparatus for a missilelike subsoil burrowing device, comprising: an axial cavity within said device bounded by end walls comprising forward and rear anvils; a hammer mounted for fore-and-aft movement between said anvils and comprising an interior chamber defined by a fixed wall and a forward working surface of area A; separate hydraulic supply-and-return lines connected between said device and a remote hydraulic source; means connecting said supply line and said chamber to bias said hammer continuously toward said forward anvil; a reaction piston having a working surface of area B where B>A, mounted in a second chamber for fore-and-aft movement of said working surface B from said forward anvil into said cavity; a hydraulic accumulator connected to said supply line and to said second chamber; means for discharging said accumulator into said second chamber after impact of said hammer on said forward anvil, said reaction piston accelerating said hammer rearwardly, and thus said device forwardly, the work thereby done on said hammer being controlled to bring said hammer to rest before striking said rear anvil.

Claim 7

Propulsion apparatus for a missilelike subsoil burrowing device, comprising: an axial cavity within said device bounded by end walls comprising forward and rear anvils; a hammer mounted for fore-and-aft movement between said anvils and comprising an interior chamber defined by a fixed wall and a forward working surface of area A; separate hydraulic supply-and-return lines connected between said device and a remote hydraulic source; means connecting said supply line and said chamber to bias said hammer continuously toward said forward anvil; a reaction piston having a working surface of area B where B>A, mounted in a second chamber for fore-and-aft movement of said working surface B from said forward anvil into said cavity; a hydraulic accumulator connected to said supply line and to said second chamber; means for discharging said accumulator into said second chamber after impact of said hammer on said forward anvil, said reaction piston accelerating said hammer rearwardly, and thus said device forwardly, the work thereby done on said hammer being controlled to bring said hammer to rest before striking said rear anvil.

Claim 8

Apparatus pursuant to claim 4, further comprising a third interior chamber defined between said fixed wall and a rear working surface within said hammer; a second reaction piston mounted in a fourth chamber for fore-and-aft movement from said rear anvil into said cavity; means for feeding hydraulic supply pressure into said third chamber thereby to bias said hammer into impacting contact with said rear anvil rather than said forward anvil; and means operatIve after said impacting contact for accelerating said second reaction piston against said hammer thus to drive the latter forwardly, and said device rearwardly.

Claim 9

Apparatus pursuant to claim 4 where the ratio B/A is in the range 5 to 20.