High impedance, high frequency nanoscale device electronics configured to interface with low impedance loads include an impedance transforming stage constructed of multiple nanoscale devices, such as carbon nanotube field-effect transistors. In an embodiment of the present invention, an impedance transforming output stage of a multistage amplifier is configured to drive a 50 ohm transmission line with unity voltage gain using multiple carbon nanotube field-effect transistors in parallel. In a further embodiment, a receiver provided for an electronically steered receive array is a monolithic, lumped-element system formed from nanoscale devices and configured to interface with the external electrical systems via a single transmission line.

A light emitting apparatus including: a plurality of light emitting elements; a drive circuit including a transistor and a capacitor having one end connected to a gate of the transistor; and a signal supply circuit for receiving a digital gradation signal and outputting an analog voltage signal to the drive circuit, including a computation circuit configured to correct the input digital gradation signal to generate a corrected digital gradation signal, in which the drive circuit is configured to conduct an auto-zero operation which reduce the gate-source voltage of the transistor to a threshold voltage by flowing the drain current to the capacitor, and the computation circuit is configured to generate the corrected digital gradation signal by multiplying a correction coefficient to the input digital gradation signal subtracted by a particular signal common to the plurality of light emitting elements.

An apparatus is described that includes an audio power amplifier having an input and an output. An alternating-current to direct-current power converter is coupled to the audio power amplifier in a single package to supply power to the audio power amplifier.

Aspects of the disclosure provide a circuit that includes a first circuit, a second circuit, and an adder. The first circuit is configured to generate a first signal by outputting and holding, at a first timing, a first stream in response to an input stream of data. The second circuit is configured to generate a second signal by outputting and holding, at a second timing, a second stream in response to the input stream of data. The adder is configured to add the first signal with the second signal to generate an up-sampled stream for the input stream of data and reduce a frequency component in the up-sampled stream generated by the up-sampling.

A pop-free single-ended output class-D amplifier includes: an input signal generator for generating an input signal; a power supply for supplying input power; a reference voltage generator for generating a reference voltage; a gain-adjustable stage for generating an amplified signal according to the reference voltage and adjusting a gain of the single-ended output class-D amplifier; a pulse width modulation module for outputting a pulse width modulation signal according to the reference voltage, the amplified signal, and the input power; a low-pass filter for low-pass filtering the pulse width modulation signal to generate an output voltage; and a logic controller for generating at least one control signal to control the reference voltage generator, the gain-adjustable stage, and the pulse width modulation module according to the input power, the reference voltage, and the pulse width modulation signal.

An electronic circuit, including, a power amplifier adapted to amplify an RF signal and provide it as output from the integrated circuit; a power source that is adapted to provide an unregulated voltage to the power amplifier; a regulator adapted to provide a regulated bias voltage; a subtracter that is adapted to accept a voltage proportional to the unregulated voltage and subtract it from the bias voltage to provide a reference voltage to the power amplifier; wherein the power amplifier is adapted to use the reference voltage to adjust the output from the power amplifier so that it will provide a stable power output.

Circuitry for reducing power consumption is described. The circuitry includes a power amplifier. The circuitry also includes a predistorter coupled to the power amplifier. The circuitry further includes a power supply coupled to the power amplifier. The circuitry additionally includes a controller coupled to the power amplifier, to the predistorter and to the power supply. The controller captures a transmit signal and a feedback signal concurrently and determines a minimum bias voltage from a set of voltages and a predistortion that enable the power amplifier to produce an amplified transmit signal in accordance with a requirement.

Differential power amplifier circuitry includes a differential transistor pair, an input transformer, and biasing circuitry. The base contact of each transistor in the differential transistor pair may be coupled to the input transformer through a coupling capacitor. The coupling capacitors may be designed to resonate with the input transformer about a desired frequency range, thereby passing desirable signals to the differential transistor pair while blocking undesirable signals. The biasing circuitry may include a pair of emitter follower transistors, each coupled at the emitter to the base contact of each one of the transistors in the differential transistor pair and adapted to bias the differential transistor pair to maximize efficiency and stability.

An amplifier circuit amplifies a signal for wireless transmission. A feedback circuit, including a capacitor, is coupled to the amplifier circuit. Components of the feedback circuit are selected based on a feedback factor such that an input impedance to the amplifier circuit has a same impedance characteristic as a feedback circuit impedance of the feedback circuit.

A method of operating a switched-mode power supply (SMPS) for supplying power to a load circuit, which draws a supply current that varies with an input signal to the load circuit is disclosed. The method comprises monitoring the input signal and controlling the amount of accumulated energy transferred for consumption by the load circuit, in use, in accordance with the input signal.

One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

A semiconductor package device comprises a radio frequency power transistor having an output port operably coupled to a single de-coupling capacitance located within the semiconductor package device. The single de-coupling capacitance is arranged to provide both high frequency decoupling and low frequency decoupling of signals output from the radio frequency power transistor.

A radio frequency system includes a power amplifier that outputs a radio frequency signal to a matching network via a transmission line between the power amplifier and the matching network. A sensor monitors the radio frequency signal and generates first sensor signals based on the radio frequency signal. A distortion module determines a first distortion value according to at least one of (i) a sinusoidal function of the first sensor signals and (ii) a cross-correlation function of the first sensor signals. A first correction circuit (i) generates a first impedance tuning value based on the first distortion value and a first predetermined value, and (ii) provides feedforward control of impedance matching performed within the matching network including outputting the first impedance tuning value to one of the power amplifier and the matching network.

A power amplifier module includes a power amplifier including a GaAs bipolar transistor having a collector, a base abutting the collector, and an emitter, the collector having a doping concentration of at least about 3×1016 cm−3 at a junction with the base, the collector also having at least a first grading in which doping concentration increases away from the base; and an RF transmission line driven by the power amplifier, the RF transmission line including a conductive layer and finish plating on the conductive layer, the finish plating including a gold layer, a palladium layer proximate the gold layer, and a diffusion barrier layer proximate the palladium layer, the diffusion barrier layer including nickel and having a thickness that is less than about the skin depth of nickel at 0.9 GHz. Other embodiments of the module are provided along with related methods and components thereof.

A power amplifier includes: first and second bias terminals to which bias voltages are respectively supplied; a first transistor having a first control terminal connected to the first bias terminal, a first terminal that is grounded, and a second terminal; a second transistor having a second control terminal connected to the second bias terminal, a third terminal connected to the second terminal, and a fourth terminal; a capacitor connected between the second control terminal and a grounding point; and a variable resistor connected in series with the capacitor, between the second control terminal and the grounding point.

Systems and methods are provided for generating an amplitude modulation signal to a switchmode power amplifier. A DC to DC switch is configured to receive a DC input voltage and to provide a DC output voltage. A low dropout regulator is configured to provide the amplitude modulation signal according to a modulation control signal received by the low dropout regulator. A control circuit is configured to establish a nominal operating power level for the power amplifier via the amplitude modulation signal and to maintain a minimum voltage difference between the DC output voltage and the low dropout regulator output. A modulator control circuit is configured to provide the modulation control signal to the low dropout regulator. The modulator control circuit provides the transition from a high amplitude to a low amplitude and a transition from the low amplitude to the high amplitude at configurable first and second slopes, respectively.

An automatic antenna impedance matching method for a radiofrequency transmission circuit. An impedance matching network is inserted between an amplifier and an antenna. The output current and voltage of the amplifier and their phase difference are measured by a variable measurement impedance, and the complex load impedance of the amplifier is deduced from this; the impedance of the antenna is calculated as a function of this complex impedance and as a function of the known current values of the impedances of the matching network. Starting from the value found for the impedance of the antenna, new values of the matching network are calculated that allow the load to be matched to the nominal impedance of the amplifier. The measurement impedance has a value controllable by the calculation processor according to the application and notably as a function of the operating frequency and of the nominal impedance of the amplifier.

Apparatus and methods disclosed herein perform gain, clipping, and phase compensation in the presence of I/Q mismatch in quadrature RF receivers. Gain and phase mismatch are exacerbated by differences in clipping between I & Q signals in low resolution ADCs. Signals in the stronger channel arm are clipped differentially more than weaker signals in the other channel arm. Embodiments herein perform clipping operations during iterations of gain mismatch calculations in order to balance clipping between the I and Q channel arms. Gain compensation coefficients are iteratively converged, clipping levels are established, and data flowing through the network is gain and clipping compensated. A compensation phase angle and phase compensation coefficients are then determined from gain and clipping compensated sample data. The resulting phase compensation coefficients are applied to the gain and clipping corrected receiver data to yield a gain, clipping, and phase compensated data stream.

A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Systems and methods are provided for amplifying multiple input signals to generate multiple output signals. An example system includes a first channel, a second channel, and a third channel. The first channel is configured to receive one or more first input signals, process information associated with the one or more first input signals and a first ramp signal, and generate one or more first output signals. The second channel is configured to receive one or more second input signals, process information associated with the one or more second input signals and a second ramp signal, and generate one or more second output signals. The first ramp signal corresponds to a first phase. The second ramp signal corresponds to a second phase. The first phase and the second phase are different.

An apparatus for amplifying power is provided. The apparatus includes a supply modulator for generating a supply voltage based on an amplitude component of a transmission signal, and a power amplify module for amplifying power of the transmission signal using the supply voltage, wherein the power amplify module includes a first power amplifier and a second power amplifier, and when an output power of the transmission signal is greater than a reference power, the first power amplifier amplifies the power of the transmission signal using the supply voltage, and when the output power of the transmission signal is equal to or less than the reference power, the second power amplifier amplifies the power of the transmission signal using the supply voltage.

A voltage converter can be switched among two or more modes to produce an output voltage tracking a reference voltage that can be of an intermediate level between discrete levels corresponding to the modes. One or more voltages generated from a power supply voltage, such as a battery voltage, can be compared with the reference voltage to determine whether to adjust the mode. The reference voltage can be independent of the power supply voltage.

An automatic gain control device includes: a variable gain adjusting unit, for adjusting an input signal by a variable gain and outputting an adjustment result; an analog-digital converting unit, for performing analog-digital conversion on the adjustment result to obtain an analog-digital conversion result; and a gain determining unit, for determining a distribution status over a predetermined period of time of a maximum or a minimum of the analog-digital conversion result, comparing the distribution status with a first distribution condition, and if the distribution status meets the first distribution condition, then keeping the variable gain unchanged, otherwise changing the variable gain and determining newly a distribution status until the newly determined distribution status meets a second distribution condition which is at least as strict as the first distribution condition.

A chuck device includes front and rear collets, a driving ring, and a driving sleeve. The driving ring and the driving sleeve can be driven hydraulically to move toward or away from each other. When the driving ring and the driving sleeve are moved hydraulically away from each other, each of the front and rear collets is moved to a release position, when the driving ring and the driving sleeve are moved hydraulically toward each other, each of the front and rear collets is moved to a clamping position.

A jaw for use in a drill chuck having a longitudinal center axis, comprising a chuck body which includes a jaw face formed on an inner surface of the chuck body and a plurality of teeth formed on an outer surface of the chuck body, the jaw face being substantially parallel to the longitudinal center axis. A ridge depends inwardly from the jaw face toward the longitudinal center axis. The ridge includes a tool engaging surface that is substantially parallel to the longitudinal center axis and has a width of between 0.020 to 0.060 inches.

A damping tool holder, such as a boring head, a chuck, or a milling cutting arbor, integrates a damping device (2), in the form of an elongated body. The damping device (2) is housed in a mounting body (3), connected by one end to the tool-holder body (1) and having at its other end an end fitting (4) for mounting a tool, whereby the mounting body (3) is equipped with at least one lubricant feed pipe (32), emptying at its front end into the end fitting (4) for mounting a tool and connected at its other end to a circular groove (102) for distributing lubricant that is provided on the front surface of the tool holder (1).

A machining system that includes an ultrasonic machining assembly, wherein the ultrasonic machining assembly further includes a machining tool; a collet adapted to receive the machining tool; and an ultrasonic transducer, wherein the ultrasonic transducer is operative to transmit acoustical vibrations to the machining tool; and a machining apparatus, wherein the machining apparatus is adapted to receive and secure the ultrasonic machining assembly, and wherein the machining apparatus is operative to transmit torque to the machining tool by applying rotary motion to the ultrasonic machining assembly.

An accessory for coupling to an attachment mechanism of an oscillating power tool includes a working end, an opposite rear end, and a fitment portion adjacent the rear end portion. The fitment portion includes a generally U-shaped opening having a central portion and a rearward portion open to the rear end, and configured to receive a post of a tool clamping mechanism. The fitment portion further includes a first plurality of openings in communication with and extending radially outward from the central portion, a second plurality of openings not in communication with and positioned radially outward from the central portion. The central portion, the first plurality of openings, and the second plurality of openings are configured to couple the fitment portion to a plurality of different configurations of attachment mechanisms for oscillating power tools.

Embodiments of the present invention generally provide chamber components with enhanced thermal properties and methods of enhancing thermal properties of chamber components including bonding materials. One embodiment of the present invention provides a method for fabricating a composite structure. The method includes applying a bonding material to a first component, and converting the bonding material applied to the first component to an enhanced bonding layer by heating the bonding material to outgas volatile species from the bonding material. The outgassed volatile species accumulates to at least 0.05% in mass of the bonding material. The method further includes contacting a second component and the enhanced bonding layer to join the first and second components.

An internal adapter for use in torque-limiting handles for interchangeable orthopedic tools contains a slidable collar component, house component, retaining ring, spring, driver component, cover and cam which engages a torque-limiting mechanism. A plurality of securing ball mechanisms releasably secure an orthopedic tool in the adapter, while a configuration of chamfered surfaces centrally stabilize the tool. A plurality of guiding chamfers located in a driver component rotationally secures the orthopedic tool.

An attachment apparatus for a reciprocating tool provides a tool holder having an angled bracket and a guide rod extending from the angled bracket. The guide rod can engage a travel slot on the reciprocating tool. An instrument such as a saw blade can be attached to the angled bracket or guide rod. The guide rod stabilizes the instrument during use. The travel slot can be defined integrally on the reciprocating tool or on an attachment to the tool. In some embodiments, a neck mount assembly is attached to the neck on the reciprocating tool. The neck mount assembly can include a frame and a guide plate. The guide plate can include a travel slot shaped for receiving the guide rod.

An interface between a receptacle body and an insert designed, in particular, as a tool or workpiece insert, comprises a receptacle body (2) having a cylindrical receiving bore (4), which is circumscribed by a first plane surface (6) extending at a right angle to the bore axis and in which a first cone surface (9) is arranged, said first cone surface being coaxial with the bore axis and being arranged so that its tapered end faces toward the plane surface. The insert (3) has a pin (15) that is disposed to be plugged into the receiving bore (4) and is circumscribed by a second plane surface (22). At an axial distance from the second plane surface (22), said pin has a second cone surface (22), the tapered end of said second cone surface being arranged so as to face toward the second plane surface. With the pin (15) inserted in the receiving bore (4), the two plane surfaces are in superimposed contact while the two cone surfaces (9, 22) can be biased relative to each other by limited twisting of the insert relative to the receptacle body.

A clamp arrangement for releasably securing an accessory to an oscillating power tool can include a tool body including a motor that drives an output member. A clamp assembly can include a first clamp member that moves relative to the accessory between a closed position wherein the clamp assembly retains the accessory and an open position wherein the first clamp member of the clamp assembly is offset from the accessory permitting removal of the accessory from the clamp assembly. A lever can have a user engagement portion and a pivot portion including a pivot axle. The lever can be pivotally coupled to the tool body about the pivot axle between a first position, wherein the clamp assembly is in the closed position and a second position wherein movement of the user engagement portion of the lever causes the clamp assembly to be moved to the open position.

A thermally zoned substrate holder including a substantially cylindrical base having top and bottom surfaces configured to support a substrate. A plurality of temperature control elements are disposed within the base. An insulator thermally separates the temperature control elements. The insulator is made from an insulting material having a lower coefficient of thermal conductivity than the base (e.g., a gas- or vacuum-filled chamber).

An adhesive layer that bonds the back surface of a plate capable of attracting a wafer and the front surface of a cooling plate together that includes a main adhesive portion, which is made of a hardened matter of a fluid adhesive, and an outer peripheral adhesive portion, gas-supply-hole adhesive portions, lift-pin-hole adhesive portions, and terminal-hole adhesive portions made of a double-faced tape. The tape portions bond the outer peripheral edge on the back surface of the plate and the outer peripheral edge on the front surface of the cooling plate together, and the outer peripheral edges of the holes on the back surface of the plate and the outer peripheral edges of these holes on the front surface of the cooling plate together.

A fastener holder includes a driving tool stem having a number of orifices, a driving tool shank engaged in the stem for engaging with a tool element and having a number of depressions formed in the shank, a number of bearing members engaged in the orifices of the stem for engaging with the depressions of the shank and for selectively anchoring the shank to the stem, and a barrel includes a relatively smaller segment for selectively engaging with the bearing members and for forcing the bearing members to engage into the depressions of the shank and to anchor and lock the driving shank to the stem and for allowing the driving shank and the tool element to be selectively rotated and driven by the stem.

A workholder to hold a workpiece, including a main body partially defining a fluid chamber, and a bladder carried by the main body with an interference fit, further defining the fluid chamber, and composed of an 80 to 100 durometer Shore A scale hardness polymer of a 12:1 to 18:1 diameter-to-wall-thickness ratio. Annular seals may further define the fluid chamber, and are disposed radially between the bladder and main body and axially adjacent the fluid chamber, and are composed of a 60 to 80 durometer Shore A scale hardness polymer. A collet is carried and driven by the bladder for gripping engagement with the workpiece.

The test fixture includes a housing, a first grip, and a second grip. The first grip and the second grip are each configured to clamp onto an upper surface and lower surface of a material coupon. The test fixture also includes an upper input jaw and a lower input jaw each configured to clamp onto the material coupon near a center of the upper surface and the lower surface of the material coupon. The test fixture is configured to load the material coupon in a first direction and a second direction. The first grip and the second grip are each configured to clamp onto the material coupon at a location which accordingly results in a desired testing ratio regardless of a variation in thickness of the material coupon.

The present invention discloses a kind of universal mounting hole means for different tool heads of electric tools, which are disposed on a mounting portion of the tool head, comprising a central hole and a plurality of long and narrow limiting holes which orient radially surrounding the central hole and disposed in distance with each other. Compared with the prior art, the present invention is applicable to various kinds of structures of the mounting seat on electrical tool and is more universal. It takes much convenience to people when changing different tool heads of electric tools, and it is benefit for storing.

An apparatus, particularly a chuck for retaining a thin part for micro-machining processing, is disclosed. The chuck is formed of a plate-shaped body having a first surface and a second surface opposite the first surface. The plate-shaped body includes a light-transmissive material, and at least one of the first surface or the second surface is a roughened surface. The chuck can be incorporated into a micro-machining system using a chuck support that allows light through to backlight a processed part for inspection.

The invention relates to a workholder (10) for holding a workpiece to be processed in a machine tool, which workholder (10) is in the form of a annular body (12) having a central through hole (14), said annular body (12) having at least one weakened area (18, 20; 34, 36, 38, 40; 50, 52, 54, 56) obtained by material removal, as well as at least one pressure chamber (22; 42, 44; 58, 60) assigned to said at least one weakened area (18, 20; 34, 36, 38, 40; 50, 52, 54, 56) that can be charged with a pressurized fluid. Said at least one weakened area (18, 20; 34, 36, 38, 40; 50, 52, 54, 56) is dimensioned and arranged so as to cause said annular body (12) to be elastically deformable in an axial and/or a radial direction (a, r). As a result, with pressure acting on said pressure chamber (22; 42, 44; 58, 60), said annular body (12) can then be deformed elastically in a well-defined manner in an axial and/or a radial direction (a, r).

A power tool has a driving shaft driving a working element, a fastening piece fastening the working element to the driving shaft having a projecting shaft insertable into the driving shaft, a locking assembly locking the projecting shaft in the driving shaft having a locking member wherein the locking member has a locking position for locking the projecting shaft with the driving shaft and a loosening position for loosening the projecting shaft with the driving shaft. At the locking position, the fastening piece is pressed towards an end portion of the driving shaft by an elastic component. The locking assembly further includes a movable member arranged outside of the driving shaft, the movable member having a first portion and a second portion which can be directly or indirectly mated with the locking member wherein a radial distance of the first portion relative to a shaft center of the driving shaft is unequal to that of the second portion relative to the shaft center of the driving shaft.

A holding jig (1, 2, 3) for a thin cylindrical work (W) includes a holding member (10, 10A, 10B) which holds the work (W) from an inner peripheral side and a diameter changing unit (25, 27) which changes a diameter of the holding member (10, 10A, 10B). The holding member (10, 10A, 10B) is made of metal and has a cylindrical shape and an elastically expandable or contractible diameter. The holding member (10, 10A, 10B) is configured with an outside diameter of the holding member (10, 10A, 10B) being held smaller than an inside diameter of the work (W) at the time of insertion into an inner periphery of the work (W) and being expanded after inserted into the inner periphery of the work (W) to hold the work (W) from an inner peripheral side of the work (W) with an outer peripheral surface in close contact with an entire inner peripheral surface of the work (W). The diameter changing unit (25, 27) applies at least one of an axial external force in a compressing direction or an axial external force in a tensile direction to both ends of the holding member (10. 10A, 10B) to change the diameter of the holding member (10, 10A, 10B).

A multi-spindle machining machine with a tool changing mechanism contains a base; a carrier including a seat to move in Z axis, a rotary shaft fixed on the seat laterally to drive the seat to rotate in A axis, and a fixing holder coupled to an end portion of the rotary shaft to fix a work piece; a tool changing mechanism including a mount mounted to the rotary shaft to rotate with the rotary shaft and a monitor fixed on the seat to measure a length of the tool clamped on a driving spindle, and including a plurality of slots to receive the tools respectively; a working head moving above the carrier and the tool changing mechanism in X and Y axes and including the driving spindle mounted on a lower end thereof to rotate axially, and the lower end of the driving spindle allowing to engage and disengage the tool.

A pin-and-collet assembly, a longwall shearer comprising a ranging arm attached to a lifting bracket with such assembly, a method for the secure fastening of one piece to another, such as securely fastening the ranging arm to the lifting bracket of a longwall shearer using such assembly as a bushing, and a method for longwall mining of ore, such as trona, using such longwall shearer. This assembly is easy to install, does not have to be tightened during longwall operation of an ore panel, and is also demountable when it is time to stop the longwall mining operation and time to remove/replace the ranging arm for maintenance and/or when the end of the ore panel is reached.

A product dispensing system includes an overcap that has a locking element extending therefrom. A container has a product disposed therein. A bracket is attached to the container. The bracket includes at least one flange and at least one slot. The at least one flange extends toward the at least one slot. A resilient member is disposed within the locking element.

The present invention is a self-locking internal adapter for D-shaped orthopedic tools. A locking ball mechanism prevents movement of the adapter components relative to each other, while a plurality of securing ball mechanisms releasably secure a D-shaped orthopedic tool in the adapter. A chamfered surface of the adapter engages a chamfer of the tool to centrally stabilize the tool in the adapter. The internal adapter may be used with driver handles, ratcheting handles and torque-limiting handles.

The invention relates to an adapter for driven tools such as drilling or milling tools, for adapting an externally fed driven tool for use in a thru coolant system comprising: a) a cylindrical inner sleeve, b) an outer sleeve adapted to rotate relative to the inner sleeve, c) a delivery pipe to deliver coolant to the outer sleeve, and d) at least one coolant flow channel through the outer sleeve and through the inner sleeve to allow flow of coolant from the delivery pipe to the collet, and e) a seal at one end of the inner sleeve having an aperture to receive the cutting tool whereby to allow the blunt end of the tool to engage the collet, in use coolant can pass through the outer sleeve, through the inner sleeve into the collet, and to the cutting tool whilst said inner sleeve rotates with said machine output spindle and the outer sleeve remains static.

A holder for a cutting tool includes a body having a first channel for receiving a stem portion of the cutting tool. The body has a second channel intersecting with the first channel. The holder further includes a plunger to be inserted in the second channel, the plunger having a third channel the cross section of which at least partly overlaps with the cross section of the first channel when the plunger is inserted into the body so as to enable the stem of the cutting tool to extend into the third channel when the stem is inserted in the first channel. The holder further includes a mechanism for locking the stem against movement relative to the body by means of the plunger. A cutting tool for use in such a holder and a cutting insert are also provided.

The present invention relates to a hole-saw assembly (10) including a hole saw (26) having at one end a plurality of cutting teeth and at the other end two shafts. The assembly includes a mandrel (16) coaxially aligned with said hole-saw and including a body having two bores there through coaxially aligned with said shafts. An annulus (20) located on top of the body is coaxially aligned with said mandrel and hole saw and includes two holes, the annulus rotatable around its longitudinal axis from a first to a second position. In the first position the annulus holes are aligned with the bores and shafts allowing the shafts to be freely insertable and removable and in the second position the holes are misaligned to lock the shafts to the annulus. The mandrel further includes a pair of driving pins (22) adapted to engage driving apertures (24) found in hole saws especially larger ones. Typically the driving pins may biased to enable the assembly to be used even with those hole saws that do not include driving apertures and that also enables easier assembly of the device. A compressible O-ring (42) may further facilitate the operation of the assembly. This device avoids the problem of thread stripping.