Stabilized piston-cylinder impact device

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation along a selected straight path on said frame,
• at least two connecting rods operatively connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotational phase and operatively connected to reciprocate said body along said selected path upon rotation of said crankshaft,
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• impact tool means operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• non-rotative guide means operatively interposed between said frame and said body and guiding said body in substantially linear reciprocation along said selected path substantially free of extraneous rotations from torques imposed on the body by angular thrust of the connecting rods from differences in manufacturing tolerances, and structural deflections and oscillations, of said crankshaft, cranks, connecting rods, body, and frame during operation of said device,
• said non-rotative guide means comprises substantially straight line track means rotationally asymmetric and substantially parallel with respect to the selected path of body reciprocation and at least one track engaging element mounted for guided engagement with the track means during body reciprocation, the track means and the track engaging element being mounted one to the frame, and one to the body.

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation along a selected straight path on said frame,
• at least two connecting rods pivoted on one or more cranks in a spaced relation for actuation thereby in substantially the same rotational phase at substantially the same crank radius and operatively connected to reciprocate said body along said selected path upon rotation of said crankshaft,
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel with said selected path,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• impact tool means operatively mounted on said frame for impact by said ram means during reciprocation thereof, said impact tool means having a principal tool axis substantially aligned with the direction of impacting motion of said ram,
• at least one of said at least two connecting rods pivoted on said body on each side of said principal tool axis, the pivot axis of each said connecting rod substantially aligned with a common pivot axis,
• reciprocative guide means operatively interposed between said frame and said body and comprising a body guide element and a frame guide element and guiding said body substantially along said selected straight path,
• said body guide element operatively engages the frame guide element at least at one point closer to the axis of said crankshaft than said common pivot axis, and at least at a second point farther from the axis of said crankshaft than said common pivot axis.

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation on said frame,
• at least two connecting rods connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotational phase and operatively connected to reciprocate said body upon rotation of said crankshaft,
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means.
• impact tool means operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• non-rotative guide means acting between said frame and said body for restricting the reciprocative motion of said body to substantially linear reciprocation substantially free of extraneous rotations,
• at least two wrist pins mounted in spaced relation on said reciprocating body, the axis of each wrist pin being substantially aligned to a common axis,
• said ram means having a principal axis substantially aligned with the direction of the impacting motion of said ram means, said wrist pins being laterally spaced, one wrist pin being on one side of the principal axis, and another wrist pin being on the opposite side.
• at least one connecting rod pivoted on each wrist pin, and
• the substantially common axis of said wrist pins is located at a longitudinal position on said body between the longitudinal mid-point and the end of said body more distant from said crankshaft, said positioning of said wrist pins acting to stabilize the motion of the body and the ram means during reciprocation thereof.

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation along a selected straight path on said frame,
• at least two connecting rods operatively connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotational phase and operatively connected to reciprocate said body along said selected path upon rotation of said crankshaft,
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• impact tool means operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• reciprocative guide means operatively interposed between said frame and said body and comprising a body guide element and a frame guide element and guiding said body in linear reciprocation substantially along said selected straight path,
• said exciter means comprises a rotary motor having a rotor mounted on said frame for rotation about a selected rotational axis substantially at right angles to said selected straight path,
• the positioning of motor, crankshaft, and connecting rods eliminates extraneous oscillatory rotations of said crankshaft about an axis parallel with said selected straight path from pulsating torque imposed on said rotor from reaction force impulses in said connecting rods during operation.

An inpact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation on said frame,
• at least two connecting rods connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotation phase and operatively connected to reciprocate said body upon rotation of said crankshaft;
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• impact tool means operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• non-rotative guide means acting between said frame and said body for restricting the reciprocative motion of said body to substantially linear reciprocation substantially free of extraneous rotations,
• said exciter means comprises a rotary motor mounted on said frame, said rotary motor having an output shaft rotatably mounted on shaft support bearings,
• said crankshaft comprises said output shaft.
• the positioning of motor, crankshaft, and connecting rods eliminates speed reduction gears, and shafts, bearings and frame supports therefor, and all extraneous vibrations generated thereby,
• at least two cranks on said crankshaft,
• said output shaft having a shaft extension extending from each end of said rotary motor, at least one of said cranks being located on each said shaft extension, said location of crankshaft and cranks to reduce structural members, and provide better balance, reduced structural and shaft deflections and extraneous vibrations generated thereby.

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation on said frame,
• at least two connecting rods connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotational phase and operatively connected to reciprocate said body upon rotation of said crankshaft.
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• an impact tool operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• reciprocative guide means acting between said frame and said body for restricting the motion of said body to substantially linear reciprocation,
• a counterweight mounted for reciprocating movement relative to said frame, said counterweight operatively connected to an auxiliary converter means for converting such rotary to reciprocating motion,
• said auxiliary converter means comprising at least one additional crank secured to said crankshaft and an auxiliary connecting rod operatively connecting each said crank to said counterweight acting to produce linear motion of said counterweight opposite that of said ram means.

An impact device comprising:

• a frame,
• a crankshaft rotatably mounted on said frame,
• exciter means operatively mounted to rotate said crankshaft,
• a body mounted for reciprocation on said frame,
• at least two connecting rods connected to said crankshaft in a spaced relation for actuation thereby in substantially the same rotational phase and operatively connected to reciprocate said body upon rotation of said crankshaft,
• ram means mounted on said body and free for reciprocation relative thereto substantially parallel to reciprocation of the body,
• resilient means interposed between said body and said ram means for converting reciprocating motion of said body to impacting motion of said ram means,
• an impact tool operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• non-rotative guide means acting between said frame and said body for restricting the reciprocative motion of said body to substantially linear reciprocation by preventing oscillatory rotative displacement of said body by any unsymmetrical action of said connecting rods on said body generated by differences in manufacturing tolerances and structural deflections in said crankshaft, cranks, connecting rods, body, and frame,
• compensating spring means mounted between said motor and said body acting to produce force on said motor in a direction opposite that produced by action of said connecting rods.

An impact device comprising:

• a frame,
• exciter-reciprocative means operatively mounted on said frame, and having a reciprocating output reciprocating at a working rate of impacting,
• a resilient coupler operatively mounted for reciprocation on said frame, said resilient coupler comprising an enclosing wall including a cylinder portion with end elements forming a total enclosed space substantially confining a selected quantity of air therein, and ram means comprising a piston with at least one shaft thereon extending in slidable sealed relation through an associated one of said end elements, said piston fitted for slidable reciprocation axially within said cylinder portion and having piston seal means operative to restrict air leakage past said piston, said piston thereby dividing the total enclosed space within the enclosing wall into separate enclosed spaces of variable volume, each said separate enclosed space confining a substantially constant quantity of air therein,
• said resilient coupler operatively interconnecting said reciprocating output and the ram means to transmit reciprocating motion of said reciprocating output to reciprocating motion of said ram means,
• impact tool means operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• flow restricting passage means for limiting compensating air flow to an amount not substantially exceeding imminent air leakage past said piston and to substantially maintain the varyingly reduced air pressure of expansion alternatingly occurring during each cycle of operation in each said separate enclosed space, thereby to substantially maintain doubly acting air spring stiffness of said resilient coupler,
• said flow restricting passage means comprising one or more openings through said enclosing wall at one or more selected points through which said compensating air is put alternately into and out of each said separate enclosed space by action of said piston reciprocation to compensate for air leakage past the piston seal means to stabilize the piston mid-excursion point during operation.

An impact device comprising:

• a frame,
• exciter means operatively mounted on said frame, and having a rotary motion output at working frequency,
• converter means operatively connected to the output of said exciter means for converting such rotary motion to reciprocating motion,
• a resilient coupler operatively mounted for reciprocation on said frame, said coupler comprising a cylinder with end elements forming an enclosed space, and ram means comprising a piston with shaft on one end thereof and extending in slidable and sealed relation through one of said end elements, said piston fitted for slidable reciprocation axially within said cylinder and having piston seal means operative to restrict air leakage past said piston, said piston thereby dividing the enclosed space within the cylinder into separate enclosed spaces,
• said resilient coupler operatively interconnecting the converter means and the ram means to transmit reciprocating motion generated by said converter means to reciprocating motion of said ram means,
• an impact tool operatively mounted on said frame for impact by said ram means during each reciprocation thereof,
• restrictive vent means in the cylinder wall and located medially of the cylinder length, through which vent means gas is bled acting to compensate for leakage past the piston and the piston shaft to stabilize the piston mid-excursion point, said vent means being restricted to bleed reduced flow of gas acting to substantially maintain reduced gas pressure on the receding end of said piston, the gas pressure being reduced by the receding motion of said piston away from the cylinder medial length position, the restricted flow of gas acting to substantially maintain double gas spring stiffness.
• said piston comprises a web, said web having an average circumferential thickness which varies from a maximum circumferential average thickness at the attachment point to said piston shaft to a minumum circumferential average thickness adjacent the walls of said cylinder,
• said piston has a flared skirt portion attached to said minimum circumferential average thickness portion of said piston and extending from said portion parallel to the axis of said piston shaft.

The method of operating an impacting device of the type wherein a rotating crankshaft having at least one crank thereon actuates resilient coupler means mounted on a frame to drive ram means into impacting motion against impact tool means upon each rotation of the crankshaft, and the resilient coupler means comprises a vented cylinder with at least one end element enclosing at least one end of the cylinder, with the ram means including a piston slidably mounted in the cylinder and arranged to close the vent and enclose an internal open space of variable volume in the cylinder upon each rotation of the crankshaft, wherein the method comprises:

• for a selected frequency w.sub.o of crankshaft rotation and a selected mass m of said ram means;
• providing a sufficiently short crank length and, in combination therewith, selecting the piston with sufficient cross-sectional area A normal to the path of piston motion and arranging the cylinder and vent location to enclose a substantially constant quantity of air of volume Ah at pressure p.sub.i upon each enclosure of the internal open space by the piston during each cycle of crankshaft rotation to determine a ratio p.sub.i A/h providing air spring stiffness k for said resilient coupler means of sufficient magnitude to limit piston travel toward said at least one end element during impacting operation to the point in piston travel at which the minimum volume of said internal open space is 0.3Ah thereby restricting such excursions within a range for which said air spring stiffness is substantially constant, and
• further providing sufficient magnitude for said air spring stiffness k, in combination with said selected mass m, to provide a magnitude of natural frequency w.sub.n of the air spring ram mass combination equal or sufficiently close to the selected frequency w.sub.o of said rotating crankshaft to insure driving said ram means during impacting operation into reciprocating excursions greater than said sufficiently short crank length thereby inducing dynamic amplification of the motion of said ram means.