Abstract: An improved version of applicant's prior bulldozer mold board assemblies is disclosed. Such prior assemblies include a mold board, a reciprocating cutter blade along the lower edge of the mold board, and a resonant beam mounted aft of the mold board.The vibration of the beam results in a reciprocating force at the node, which is undesirable in applicant's prior device. The present invention improves on applicant's former construction by pivotably supporting the mold board so that the mold board is pivotable about a transverse axis. The resonant beam is connected at its central node to the mold board. In this fashion, the reciprocating transverse forces on the node of the resonant beam are transmitted to the pivotably mounted mold board to agitate the material in contact therewith.

Abstract: The present invention provides an improved mechanism for positioning the weight relative to the resonant beam in resonantly driven impact systems.

Abstract: An improved penetrating tool for pavement breakers is disclosed. The tool of the present invention has a flange with a striking surface which extends in the direction of motion of the vehicle. The striking surface is curved so that the closing angle, defined as the difference between the angle of motion and the angle of inclination of that portion of the striking surface in contact with the pavement, is constant throughout the entire stroke of the tool. The constant closing angle should be within the range of about 6.degree.-18.degree., preferably about 15.degree..

Abstract: A front end loader has a loading bucket secured to a tractor and a transversely elongate cutter blade closely spaced forward of a lower front edge of the bucket. Improved apparatus for reciprocating the blade in forward and aft directions relative to the front edge of the bucket is disclosed. A force transmitting beam has a resonant frequency with at least one node and first and second anti-nodes at the resonant frequency. A source of vibrations at or near the resonant frequency is coupled to the beam near the first anti-node to vibrate the second anti-node about a neutral position. The beam is secured near one node so as to locate the neutral position of the second anti-node in spaced relationship from the cutting blade within striking distance thereof. The second anti-node thus applies unidirectional force impulses to the blade in a forward direction as the second anti-node vibrates to drive the blade intermittently forward.

Abstract: A front end loader has a loading bucket secured to a tractor and a transversely elongate cutter blade closely spaced forward of a lower front edge of the bucket. Improved apparatus for reciprocating the blade in forward and aft directions relative to the front edge of the bucket is disclosed. A force transmitting beam has a resonant frequency with at least on node and first and second anti-nodes at the resonant frequency. A source of vibrations at or near the resonant frequency is coupled to the beam near the first anti-node to vibrate the second anti-node about a neutral position. The beam is secured near one node so as to locate the neutral position of the second anti-node in spaced relationship from the cutting blade within striking distance thereof. The second anti-node thus applies unidirectional force impulses to the blade in a forward direction as the second anti-node vibrates to drive the blade intermittently forward.

Abstract: A continuous miner includes a pair of resonant beams for driving a cutting blade rigidly secured to their lower anti-nodes. By mounting the beams so that they can pivot about both upper and lower nodes, the miner may be operated to make either vertical or horizontal cuts. When making vertical cuts, the beams are pivoted upward about their upper nodes to drive the blade in an upward arc in front of the miner, the blade being rearwardly off-set from the center line of the beams to reduce blade drag. To make horizontal cuts, the beams are maintained substantially vertically as the miner is driven forward. The precise angle of the blade relative to the ground may be adjusted to reduce blade drag by tilting the beams an appropriate amount about their lower nodes.

Abstract: A rail forger for reforming worn rails is disclosed. The forger includes a mobile frame capable of travel along the railway and a pair of forging shoes pivotally suspended from the frame. The forging shoes are adapted to travel along either side of the rail and are shaped to conform to the desired rail profile. By periodically and simultaneously applying a force to each forging shoe, the rail is impact forged and returned to its desired profile. A resonant system comprising a pair of horizontally suspended resonant beams is excited by a pair of eccentric weights at the upper ends of the beams to drive the associated forging shoes at the lower ends of the beams against the rail.

Abstract: A pavement breaker including a mobile carrier vehicle is disclosed. A beam is provided having a resonant frequency with a pair of nodes spaced from the input and output ends of the beam and anti-nodes at each end and at the center. An oscillator is fixed to the input end of the beam to vibrate the beam at at least near its resonant frequency. The beam is mounted to the carrier vehicle at the node near the input end of the beam. A weight is superimposed over the beam at the node near the output end and has a bearing surface adapted to bear downwardly against the beam at that node. The weight is coupled to the vehicle to control the vertical position of the weight. A tool depends from the output end of the beam, and strikes the surface on which the vehicle rests at the vibration frequency of the beam as the tool vibrates responsively to vibrations of the beam. The reaction force generated by the tool is substantially absorbed by the weight and not transmitted to the carrier vehicle.

Abstract: A plasticizer for melting raw plastic feed material and the like includes a pair of resonant beams horizontally mounted on a frame and having a plasticizing chamber defined between a pair of vertically aligned anti-nodes. A pair of pistons projecting from said anti-nodes define movable walls of the chamber which are vibrated by resonantly exciting the beams. Raw plastic feed material held within the chamber may be subjected to relatively high pressure, including a superimposed pressure component imparted by the vibration of the resonant beams. Such pressure and vibration act to melt the raw plastic feed material which may be discharged from the chamber by lowering the uppermost beam to evacuate the chamber.

Abstract: A system for installing an elongate fastener which is partially threaded in a workpiece is provided. The system includes a mass which is resiliently mounted so that it is reciprocatable at a resonant frequency. The mass is excited so that it reciprocates at least near its resonant frequency. A chuck is provided with a front portion adapted to releaseably support the fastener, and a back striking surface. The chuck is located so that the reciprocating mass intermittently impacts the striking surface of the chuck to drive the fastener into the workpiece until the threaded portion of the fastener engages the workpiece. Once the threaded portion of the fastener engages the workpiece, the front portion of the chuck is rotated to correspondingly rotate the fastener to complete the installation of the fastener in the workpiece.

Abstract: A bulldozer having a transversely elongate cutter blade closely spaced from the bottom edge of the mold board is disclosed. The cutter blade is mounted for reciprocal motion in forward and aft directions relative to the mold board. Unidirectional force impulses are applied to the cutter blade in a forward direction to drive the blade intermittently forward without aft motion. Preferably, the unidirectional force impulses are applied by first and second matched force transmitting beams. Each beam has two divergent approximately straight legs that meet at a juncture to form an acute, approximately 90.degree. angle, a node at the juncture, an input anti-node at the end of one leg, and an output anti-node at the end of the other leg at the input frequency. A source of vibrations at or near the resonant frequency is coupled to the input anti-node and the output anti-node is disposed in spaced aft relationship from the cutter blade within striking distance thereof.

Abstract: A resonantly driven tool for forming a trench in base material is disclosed. A channel member is adapted to be aligned with the path of the trench to be formed. The channel member has a floor inclined upwardly toward the rear, and oppositely disposed sides projecting upwardly from the floor. The channel member is open front and rear, and the channel member is advanced along the path of the trench to be formed. A cutting blade is located at the leading end of the floor of the channel member, and is mounted so that it can reciprocate relative to the channel member. The cutting blade engages the material in which the trench is to be formed as the channel member is advanced. A resonant system is provided with an output vibratory in at least near resonance. The resonant system is supported to move with the channel member, and is operatively coupled to the cutting blade to drive the cutting blade intermittently forwardly.

Abstract: A surface impact system including a mobile carrier vehicle is disclosed. A beam is provided having a resonant frequency with a pair of nodes spaced from the input and output ends of the beam and anti-nodes at each end and at the center. An oscillator is fixed to the input end of the beam to vibrate the beam at at least near its resonant frequency. The beam is mounted to the carrier vehicle at the node near the input end of the beam. A weight is superimposed over the beam at the node near the output end, and has a bearing surface adapted to bear downwardly against the beam at that node. The weight is coupled to the vehicle to control the vertical position of the weight. A tool depends from the output end of the beam, and strikes the surface on which the vehicle rests at the vibration frequency of the beam as the tool vibrates responsively to vibrations of the beam. The reaction force generated by the tool is substantially absorbed by the weight and not transmitted to the carrier vehicle.

Abstract: An oscillator producing vibrations at an operating frequency near, but different from, the resonant frequency of a resonant system is coupled to its input and the resonant system is supported a predetermined distance from its free ringing node(s) at position(s) corresponding to the effective node(s) for the operating frequency. The oscillator is controlled to maintain the operating frequency at a predetermined constant value, which keeps the effective nodes at the same position as the load driven by the output of the resonant system varies.