Abstract: A sheet manufacturing apparatus includes a classifier unit configured to classify by air flow an introduced material that has been introduced, a screening unit configured to allow a classified material, which comprises fibers, that has been classified by the classifier unit to pass through a plurality of openings to screen the classified material, and a forming unit configured to use a passed material that has passed through the openings to form a sheet. The classified material is supplied to the screening unit by the air flow.

Abstract: A multi-deck screening assembly includes a plurality of vertically-stacked downwardly-sloping screen decks, each with grading apertures through which under-sized material may pass, while over-sized material passes over a lower discharge end of each screen deck. The screen decks are mounted on a common frame, which is mounted on a chassis and provided with vibration device. The screen decks include an upper deck, an intermediate deck below for receiving under-sized material from the upper deck, and a lower deck below the intermediate deck for receiving under-sized material from the intermediate screen deck. A first chassis-mounted stockpile conveyor receives over-sized material from the lower deck, a second chassis-mounted stockpile conveyor receives over-sized material from the intermediate deck, and a third stockpile conveyor receives over-sized material from the upper deck.

Abstract: Methods for preparing parcels for final sorting. The methods include dividing a mass flow of parcels into individual streams, separating and singulating the parcels in each stream, delivering each stream at a steady rate to a human operator that faces and culls the parcels, reading identifying indicia on the parcels, delivering the scanned parcels to a presorter in parallel lanes, and selectively discharging parcels from the lane closest to a side of the presorter off the side at multiple discharge points.

Abstract: A dispensing method is disclosed that includes the following steps: a cleaning sleeve is provided to surround a spray member. A first fluid is previously dispensed from a first fluid outlet of the spray member. A second fluid is sprayed from a second fluid outlet of the cleaning sleeve to clean the spray member. The cleaning sleeve is opened or slid away from the spray member, such that the first fluid outlet of the spray member is exposed to a substrate. The first fluid is dispensed from the first fluid outlet of the spray member to the substrate.

Abstract: The centrifugal compressor is provided with a casing, a rotating shaft which is supported inside the casing, an impeller which is arranged on the rotating shaft and rotates to compress a fluid, and a washing liquid injection device which injects a washing liquid into a flow path formed by the impeller and the casing. The washing liquid injection device is provided with a plurality of nozzles which are arranged along a circumferential direction of the rotating shaft to inject the washing liquid into the flow path and a plurality of chambers which communicate with each corresponding nozzle among the plurality of nozzles and supply the washing liquid to the corresponding nozzle.

Abstract: A fluid is directed toward a surface of an optical element based on a first flow pattern, the surface of the optical element including debris and the fluid directed based on the first flow pattern moving at least some of the debris to a first stagnation region at the surface of the optical element; and the fluid is directed toward the optical element based on a second flow pattern, the fluid directed based on the second flow pattern moving at least some of the debris to a second stagnation region on the surface of the optical element, the second stagnation region and the first stagnation region being different locations at the surface of the optical element. Directing the fluid toward the surface of the optical element based on the second flow pattern removes at least some of the debris from the first stagnation region.

Abstract: A system includes a UV light source and an optical medium coupled to receive UV light from the UV light source. The optical medium is configured to emit UV light proximate to a surface from which biofouling is to be removed once the biofouling has adhered to the protected surface. A method corresponds to the system.

Abstract: A cylinder head cleaning method capable of cleaning a cylinder head with an enhanced foreign matter removing rate. The method is used to clean a cylinder head (1) having therein a water jacket (15) including a narrow space portion (Z) having a narrow flow path and a large space (Y) having a flow path wider than the narrow space portion (Z), and the cylinder head (1) further having holes (12A-12R, 13, 14, 16A-16C) communicating with the water jacket (15). Cleaning nozzles (28A, 28C) are inserted into the water jacket (15) from the holes (16A, 16C) selected from the holes (12A-12R, 13, 14, 16A-16C), clearing liquid is ejected from the cleaning nozzles (28A, 28C) toward the narrow space portion (Z), and the cleaning liquid flowing from the narrow space portion (Z) to the large space (Y) is discharged to the outside of the cylinder head (1) from the hole (16B) communicating with the space (Y).

Abstract: A nozzle cleaning period management device is provided with a cleaning device that cleans suction nozzles that are used in order to perform vacuum retention of an electronic component, a flow rate measurement device for measuring a flow rate that flows through the suction nozzles, a reduction amount calculation device for calculating a unit flow rate reduction amount of the flow rate of the suction nozzle per a number of times of mounting of electronic components on the basis of a flow rate difference before and after cleaning, which is measured by the flow rate measurement device, and an estimation device for estimating a cleaning period, which subsequently cleans the suction nozzles, on the basis of the unit flow rate reduction amount, which is calculated by the reduction amount calculation device, and a flow rate after cleaning.

Abstract: A method and a device (50) for removing fragments and/or particles from containers, such as in particular glass tubes (5), provides means for adjusting the electrostatic force (40) in the tubes (5) and means for removing (60) of the fragments. The means for removing (60) can comprise a jet of fluid, of measured speed, put in the containers (5) by a nozzle (2), whereas the means for adjusting the electrostatic force (40) can comprise an element (1) for putting an electrically conducting fluid (8) with a measured resistivity in the containers (5). This way, the fluid (8), for example ionized air, acts in order to reduce and/or eliminate the electrostatic charge, and therefore the electrostatic force, between the fragments (30) and the surface of the containers, assisting the removal by means of jets of fluid or by suction means.

Abstract: The present invention is directed toward a movable airborne contaminant control system having a retractable/extendable booth attached in a sealing manner to a ventilation unit, preferably mounted on wheels. The ventilation unit includes a filter assembly that opens into the work are formed by the booth. Front doors support air filters. In operation, the ventilation unit draws air in a longitudinal laminar flow over one or more work pieces. The filter assembly captures both particulates and VOCs to allow the exhaust air to include an extremely low contaminant load.

Abstract: The present invention discloses a method of utilizing refuses in urban and rural areas. The method includes a refuses collection step, a refuse distributing step, a primary magnetic separation step, a primary crushing step, a primary elutriation and floatation step, a uniform cutting step, an acidification and anaerobic treatment step, a selection and separation step, a buffering and adjusting step, an additional anaerobic treatment step and a sludge sedimentation and concentration step. The present invention can make the anaerobic treatment method continuatively dispose the refuses, thereby thoroughly solving the problem that non-anaerobic refuses such as waste plastics, water fiber etc. can not be recycled and completely recycling resources in the refuses.

Abstract: A process for remediating salt-impacted soils includes forming a heap of salt-impacted soil on an impermeable surface; irrigating the salt-impacted soil heap with at least one amendment solution; and collecting a leachate containing sodium ions at a base of the heap. A system remediates salt-impacted soil.

Abstract: A rolling system, particularly a cold-rolling system for cold-rolling a metal strip (2): having at least one cold-rolling stand (1) an unwinding device (3) upstream of the cold-rolling stand (1), a unit (10) connected between the unwinding device (3) and the cold-rolling stand (1), including at least three rolls (6, 7, 8) each rotationally driven about a rotational axis (6A, 7A, 8A). Each roll (6, 7, 8) can be adjusted individually or together in the direction of the respective rotational axis (6A, 7A, 8A) and in a direction transverse to the rotational axis (6A, 7A, 8A) by a driving and adjusting device (11).

Abstract: A flexible roll-die forming machine for variable cross-section parts includes: a feeding device and a flexible roll-die forming unit; wherein the flexible roll-die forming unit includes at least a set of flexible roll-die forming devices; when two or more sets of the flexible roll-die forming devices are provided, the flexible roll-die forming devices are connected in sequence; wherein the feeding device is arranged at a front end of the flexible roll-die forming unit and is connected to an adjacent flexible roll-die forming device. The present invention effectively solves problems that conventional flexible roll-die forming machines are not able to produce narrow part with variable cross-sections, and the forming accuracy is poor. The present invention also reduces the amount of shafts controlled by servo motors, so as to simplify the controlling system, improve system operation reliability and simplify maintenance.

Abstract: Pilger rolling train, which operates continuously for producing a tube, includes a pilger rolling mill for reducing the diameter of a hollow blank to form the tube, a first buffer for a plurality of tubes, wherein the first buffer has a device for bundling a plurality of tubes in a bundle, an annealing furnace for simultaneous annealing of a plurality of tubes, a second buffer for a plurality of tubes, wherein the second buffer for the tubes has a device for separating the plurality of tubes out of a bundle, and a straightening machine for straightening the separated tubes in succession, wherein the devices are disposed, in the direction of flow of the tube, in the aforementioned sequence, and wherein an automated transport device for the tube is provided between, respectively, the pilger rolling mill, the first buffer, the annealing furnace, the second buffer and the straightening machine.

Abstract: A method influences the geometry of a rolled item in a controlled manner. In the method, the rolled item is transformed from an initial condition into an intermediate or final condition by rolling with the aid of a rolling stand having at least one processing assembly. An improvement in the geometry of the rolled item, particularly during processing of asymmetric rolled items, is achieved in that the at least one processing assembly is operated in a force-controlled manner on the basis of a desired force.

Abstract: A billet (2) is rolled to a rod (3) in a rolling mill. The rod (3) exits the rolling mill with a finishing temperature (TE1). A rear laser measurement device (8) arranged downstream of the rolling mill detects the head end and the speed (v) of the rod (3). The detected speed (v) of the rod (3) is integrated to its length and an instantaneous length (L) of the rod (3) is determined. Dependent on the determined instantaneous length (L) of the rod (3), cutting commands (S) to a rear shears (5) arranged downstream of the rolling mill are provided for cutting the rod (3) in sections (6) of predetermined length (L0). The sections (6) of the rod (3) are cooled down in a cooling bed (7).

Abstract: A fiber optic component cleaning device includes a body, a feed spool mounted for rotation in the body, a take-up spool mounted for one-way rotation in the body and a central support assembly. A plunger is mounted for movement in the central support assembly and a drive is operably connected to the take-up spool and to the plunger. A cleaning material is wound onto and fed from the feed spool and to the take-up spool. A reservoir assembly is mountable to the body to apply a cleaning solution to the cleaning material.

Abstract: A system and method provide a material with uniform micro-structure. In an embodiment, an equal channel angular extrusion system includes an interior mandrel. The interior mandrel includes an expanding shear material section and a contracting shear material section. In addition, the system includes a material. The material is disposed about a portion of the interior mandrel. Moreover, the system includes a pressure application device. The pressure application device applies pressure to the material to force the material to contact the expanding shear material section to provide an expanded post-shear material section. Pressure from the pressure application device applies pressure to the material to force the expanded post-shear material section to contact the contracting shear material section to provide a contracted shear material section.

Abstract: A guide pin assembly for metal forming dies includes a cylindrical guide pin body with an external retainer groove adjacent one end thereof in which a retainer ring is received. An annular guide pin ring with an outside diameter greater than the pin body, has a counterbore adjacent the outside end thereof and a retainer groove in a medial portion thereof which receives the outer portion of the retainer ring to securely interconnect the pin body and the ring and thereby form an enlarged head at one end of the pin body which positively limits reciprocal motion between two associated die members. A circular guide pin head cap covers the outer end of the head ring, and includes a support collar that is closely received in the counterbore of the ring, and engages the retainer ring to securely hold the same in place.

Abstract: Flanging press for folding over a flange of a component, preferably of a vehicle part, the press being arranged in a stationary manner and including at least the following: (a) a basic structure with a flanging bed, against which the component can be pressed in a pressing direction in order for the flange to be folded over, (b) a flanging die unit with a flanging die for folding over the flange, (c) and a pressing drive for generating a pressing force which acts on the component in order for the flange to be folded over, (d) wherein the flanging die and the flanging bed can be moved relative to one another in the pressing direction by the pressing drive in order for the pressing force to be exerted, characterized in that (e) the pressing drive includes a bellows which can be subjected to the action of pressurized fluid, preferably compressed gas, and, under the action of pressure, acts on the flanging die unit or the flanging bed in the pressing direction and thus generates at least some of the pressing force

Abstract: A tab is provided for a can end. The can end includes an end panel and a scoreline defining a tear panel in the end panel for providing an opening in the can end. The tab includes a body having first and second opposing ends, a nose portion located at or about the first end, a lift portion located at or about the second end, and a rivet receiving portion disposed proximate the nose portion. The rivet receiving portion includes a rivet hole. A first rivet extends outwardly from the end panel and fastens the rivet receiving portion of the tab to the can end. A second rivet extends outwardly from the end panel to cooperate with a portion of the body proximate the lift portion.

Abstract: In a center hole forming method, an object to be processed is inserted in a die hole and a shaft is drawn from the object. A load toward a first axial end surface of the object is applied to a second axial end surface of the object without taking out the object from the die hole. A diameter of the first axial end surface is smaller than a diameter of the second axial end surface. A center hole is formed in the first axial end surface by pressing a counter punch against the first axial end surface in a state that the load is applied to the second axial end surface.

Abstract: An apparatus for mounting a blind rivet, configured to mount the blind rivet having a rivet body and a mandrel on a board, may include a rivet holder accommodating a mandrel therein and pressing a rivet head towards the board, a mandrel holder positioned inside the rivet holder and moving separately from the rivet holder to hold and pull the accommodated mandrel, and an impactor positioned inside the rivet holder to accommodate the mandrel holder therein and applying pressure to the mandrel holder holding the mandrel, thus lifting the mandrel holder together with the mandrel.

Abstract: The magnetic base assembly includes an electromagnet assembly with a top surface open magnetic pole. A shunt plate is magnetically held to the top of the electromagnet. A canting or tilting of the shunt plate results when accidental side or pulling away contact is made between a riveting processing tool and an extending portion of the aircraft part being riveted as the tool is moved from one riveting location to another. The canting or pull off of the tool prevents damage. The operator can observe the tool canting and stop the tool movement or a micro switch or proximity switch senses the canting or tilting automatically so that the tool can be stopped before damage occurs. The magnetic field can be dynamically controlled to provide adequate pulldown force for the riveting function but a breakaway force less than the amount which would cause damage.

Abstract: Fastener delivery apparatus for automatically selecting and delivering fasteners such as rivets to a setting tool. The fasteners are pre-loaded in a package and dispense via at least one fastener delivery tube that interconnects the setting tool to a fastener feeder device. The fastener feeder device releases selected fasteners from the package into the delivery tube. The fasteners are transportable individually or in groups in the tube from the feeder device to the tool.

Abstract: A hub die-casting mold comprises a lower mold, a side mold, and an upper mold that are combined to form a hub casting cavity, where the lower mold is disposed on a lower mold plate, and the side mold is formed by abutting four sections of arc portions which are slidably connected to the lower mold plate, where the four sections of arc portions are divided into two groups that are respectively located at the left and right sides of the lower mold, and included angles from 3° to 10° are set between sliding tracks of two sections of arc portions in each group and a left-right diameter of the lower mold.

Abstract: An automotive disk brake assembly installed in an automobile having a wheel. The assembly includes a floating caliper supporting an inner and outer brake pad and a brake rotor having a disk, and a hat, and wherein the hat is bolted to the wheel. A hydraulic cylinder is adapted to push the inner brake pads into the disk surface, causing the floating caliper to move bringing the outer brake pad into contact with the disk. Finally, the rotor is made such that a complete 100 kilometer per hour, 0.9 gross vehicle weight braking causes the disk to expand in thickness by at least 0.15 mm and to cool to shrink in thickness, relative to its expanded thickness, by at least 0.1 mm within 60 seconds of the cessation of braking, in an ambient temperature of less than 30° C.

Abstract: The present disclosure is directed to processes comprising irradiating an aggregate of chemically bonded or otherwise associated nanoparticles with a light source capable of providing multiphoton excitation, the light source directed at a focal point volume including the aggregate and having sufficient energy to disrupt or fuse the aggregate within the focal point volume to form nanoscale deposits of the nanoparticles.

Abstract: A selective laser sintering method reduces a warping deformation of a three-dimensional shaped object, the warping deformation being due to the scanning of a light beam. The manufacturing method is a method for manufacturing a three-dimensional shaped object by alternate repetition of a powder-layer forming and a solidified-layer forming, wherein a scanning of the light irradiation is divided into light beam-scannings “A” and “B”, the light beam-scanning “A” being for the light irradiation of a peripheral portion corresponding to a periphery of the three-dimensional shaped object, and the light beam-scanning “B” being for the light irradiation of an internal portion corresponding to a region of the three-dimensional shaped object, the region being located inside the periphery. In particular, the peripheral portion is subjected to a discontinuous light beam-irradiation in the light beam-scanning “A” such that an irradiation path of the light beam is divided into a plurality of sub-irradiation paths.

Abstract: A forming die assembly includes an upper die including a first backup member and a first press member that is attached to the first backup member, has an L shape in a vertical sectional view, and is heat-resistant; and a lower die including a second backup member and a second press member that is attached to the second backup member, has an L shape in the vertical sectional view, and is heat-resistant. The first press member and the second press member press upper and lower surfaces of a workpiece accommodated in a press space that is formed between the first press member and the second press member, so as to produce a forged product.

Abstract: A method of fabricating a material having a high concentration of a carbide constituent. The method may comprise adding a carbide source to a biocompatible material in which a weight of the carbide source is at least approximately 10% of the total weight, heating the carbide source and the biocompatible material to a predetermined temperature to melt the biocompatible material and allow the carbide source to go into solution to form a molten homogeneous solution, and impinging the molten homogeneous solution with a high pressure fluid to form spray atomized powder having carbide particles. The size of a particle of carbide in the atomized powder may be approximately 900 nanometers or less. The biocompatible material may be cobalt chrome, the carbide source may be graphite, and the fluid may be a gas or a liquid.

Abstract: The present application relates to hollow metal nano particles.

Abstract: A method for making a plurality of metallic nanowires includes combining a metallic precursor with a solvent to form a metallic precursor solution. A quantity of oxalic acid is added to the metallic precursor solution to form a reduction solution. A plurality of nanowires are precipitated out from the reduction solution.

Abstract: A process for manufacturing silver nanowires is provided, wherein the recovered silver nanowires have a high aspect ratio; and, wherein the total glycol concentration is <0.001 wt % at all times during the process.

Abstract: The present invention provides a silver nano-particle production method which is safe and simple also in terms of scaled-up industrial-level production, in a so-called thermal decomposition method in which a silver-amine complex compound is thermally decomposed to form silver nano-particles. A method for producing silver nano-particles comprising: mixing an aliphatic hydrocarbon amine and a silver compound in the presence of an alcohol solvent having 3 or more carbon atoms to form a complex compound comprising the silver compound and the amine; and thermally decomposing the complex compound by heating to form silver nano-particles.

Abstract: A cutting insert is configured to include: a first portion having a rake face, a flank face, a cutting edge, and a face facing an insert attachment portion at an end of a tool main body; and a second portion having a side surface including at least one flat plane that is parallel to a center line of a tool or inclined at a prescribed angle to the center line. The second portion extends continuously to a region surrounded by the face of the first portion. The second portion is fitted into the tool main body to position the cutting insert and to prevent the cutting insert from rotating.

Abstract: A rotatable chuck for clamping a shank portion of a rotatably operating machining tool includes a rotatable chuck body provided with a cylindrical bore concentric with a rotation axis of the chuck body. The circumferential surfaces of a clamping portion of the bore are arranged to apply a clamping force around the circumference of the shank portion of the tool when it is mounted in the chuck to fixate the tool in the chuck. The chuck is provided with auxiliary pull out preventing means for preventing inadvertent pull out of the tool in the axial direction of the bore during machining operation, as well as auxiliary rotary preventing means for preventing inadvertent rotation in at least one direction in relation to the chuck during machining operation.

Abstract: Provided is a tool holding structure capable of effectively preventing a cutting tool from coming off a chuck portion. An outer fitting portion A is formed in an outer face of a shank portion 2 of a cutting tool T and an inner fitting portion B is formed in an inner face of a chuck portion 12 of a tool holder. A fitting member 20 is provided to be fitted to the outer fitting portion A and the inner fitting portion B respectively. The fitting member 20 includes a protruding portion 22 which protrudes from an outer circumference of the shank portion 2 when fitted to the outer fitting portion A. A guide groove 18 is formed for guiding the protruding portion 22 of the fitting member 20 from an open side of an inner space 13 to the inner fitting portion B.

Abstract: A machining method for at least one shaping machining operation can include carrying out a machining operation over a first distance using a cutting tool which is subjected to axial oscillations as it moves forward, then reducing the amplitude of the axial oscillations while continuing to drive the cutting tool in terms of rotation.

Abstract: Systems and method relating to machining parts include a CNC system including CNC machining tools, and a computer including a processor and a computer-readable medium, wherein the computer-readable medium encodes instructions of a single NC program that, when run on the processor, causes the computer to control a selected CNC machining tool to perform operations including alternating between (i) moving the selected CNC machining tool along a semi-finishing toolpath segment using a first set of spindle speed and feed rate values to remove a next portion of rough stock material in a next region of a part being manufactured, and (ii) moving the selected CNC machining tool along a finishing toolpath segment to remove a semi-finishing thickness portion of the part in the next region, wherein the first set of spindle speed and feed rate values are different from the second set of spindle speed and feed rate values.

Abstract: Bell-shaped milling cutter for producing preferably profiled, arcuate grooves, has a main body in the form of a circular disk and a plurality of cutting edge carriers which extend substantially perpendicularly to the plane of the main body and which are arranged in succession in the peripheral direction along a circular path about the center of the main body and are mounted releasably to the main body. To provide a bell-shaped milling cutter having the features set out in the opening part of this specification, which permits simplified and less expensive production of arcuate grooves without having to forego the precise arrangement and orientation of the cutting bits of the known bell-shaped milling cutters, provided at the main body are positioning devices which permit mounting of the cutting edge carriers in a plurality of mutually different radial spacings on the main body.

Abstract: On the perimeter of a head (14) that is bonded on one end of the shank (12) of a T-shaped cutter, multiple end cutting edge sections (16) with a cutting edge (16a) on the tip side of the T-shaped cutter (10) and multiple upper edge sections (18) with a cutting edge (18a) on the base end side are disposed alternating in the circumferential direction of the T-shaped cutter. The cutting edges (16a, 18a) of the end cutting edge sections (16) and the upper edge sections (18) form an integral structure with the shank (12) and the head (14).

Abstract: A double-sided, trigon cutting insert has three three major cutting edges formed at an intersection between a first planar side surface portion and first and second surfaces, and three minor cutting edges formed at an intersection between a second planar side surface portion and first and second surfaces. A planar rake surface extends radially inward and downward from each major cutting edge, and a rounded rake surface extends radially inward and downward from each minor cutting edge. An insert-receiving pocket of a cutting tool includes a planar bottom support surface, a first planar side support surface, a second planar side support surface, and a third planar side support surface. Each rounded rake surface is formed with a radius, R, that causes only a high point of each minor cutting edge to contact a workpiece during a machining operation.

Abstract: A cutting insert includes: two opposite end surfaces; a peripheral side surface extending between the end surfaces; and plural cutting edge sections that are formed along an intersecting ridgeline portion between the peripheral side surface and each of the end surfaces. Each of the cutting edge sections includes a corner cutting edge, a major cutting edge, and a minor cutting edge. A non-cutting intersecting ridgeline area extending between adjacent cutting edge sections on one end surface is located adjacent, via the peripheral side surface, to at least a part of the corner cutting edge and the major cutting edge of an associating cutting edge section on the other end surface.

Abstract: A table saw has a base assembly, a table assembly supported by the base assembly, and a saw assembly supported by at least one of the table assembly and the base assembly. The saw assembly includes a saw blade extending through the table assembly. The base assembly has at least one tube connected to the table assembly.

Abstract: A table saw assembly in one embodiment includes a base portion, a saw blade opening, a saw assembly and a first extension. The base portion includes a base work piece support surface which defines a support plane. The saw blade opening is defined in the base work piece support surface. The saw assembly includes a saw blade which is positionable to extend upwardly through the saw blade opening. The first extension includes a first extension work piece support surface which is pivotable with respect to the base portion between a first position and a second position. In the first position, the first extension work piece support surface is coplanar with the base work piece support surface. In the second position, the first extension work piece support surface is located above the support plane.

Abstract: A table saw assembly includes a base portion with a base work piece support surface which defines a support plane and a saw blade opening. A saw blade is positionable to extend upwardly through the saw blade opening. A first extension includes a first extension work piece support surface which is pivotable with respect to the base portion between a first position coplanar with the base work piece support surface and a second position above the support plane. A second extension includes a second extension work piece support surface which is pivotable between a third position coplanar with the base work piece support surface and a fourth position above the support plane. The table saw assembly includes a handle located above the work piece support surface and accessible by a user when the first extension is in the second position and the second extension is in the fourth position.

Abstract: A power tool includes a housing, a motor, and a drive mechanism. The drive mechanism includes a driven gear that is rotated by the motor. The driven gear is vertically-oriented within the housing and has an upper portion and a lower portion. The drive mechanism also includes a connecting rod coupled to the driven gear to translate rotary motion of the driven gear into reciprocating motion, and an output shaft coupled to the connecting rod to reciprocate relative to the housing through a cutting stroke and a return stroke. The drive mechanism further includes a counterweight coupled to the driven gear for rotation with the driven gear. The counterweight moves through the upper portion of the driven gear during the cutting stroke of the output shaft, and moves through the lower portion of the driven gear during a return stroke of the output shaft.