Abstract: A mechanical pencil with automatic lead advance in which a slider is temporarily locked at the time when a rearward thrust applied to the pencil tip is released. The slider is locked by an arrangement in which a movable locking tube is disposed around the slider. The locking tube can be inclined relative to the longitudinal axis of the pencil by a spring device so that the slider, when retracted, can be temporarily locked by the inclination of the locking tube.

Abstract: A mechanical pencil with automatic lead feed has a clamping mechanism for clamping a lead in such a manner that it holds the lead steadily against rearward movement but easily permits the lead to move forwardly. A lead tube is fixed at its rear end to the front end of a housing to guide and protect the lead. A sensor is slidably held in the front end of the housing and extends along the lead tube to sense the wear of the lead during writing. A lead advancing mechanism is actuated by the sensor and has a holder for frictionally holding the lead and an elastic member for urging the holder forwardly.

Abstract: A knock type sharp pencil provided in its outer cylinder with a core holding mechanism composed of an inner cylinder coaxially arranged in the outer cylinder, a lead chuck inserted in the inner cylinder and including a chuck portion projecting out of the front end of the inner cylinder, a chuck ring inserted between a flange portion of the inner cylinder and the chuck portion of the lead chuck, a core case provided at its rear end with a knock portion and connected to the rear end of the lead chuck, and a spring means arranged in the inner cylinder and inserted between the flange portion of the inner cylinder and the front end portion of the core case, the spring means urging the core case backwardly.

Abstract: A mechanical pencil including a main body divided into first and second members which are rotatable relative to one another. An inner mechanism is provided, primarily in the first member of the body, including a chuck for gripping leads, a chuck tightening member for tightening the chuck disposed around the chuck, a chuck tightening member receiver, and a lead case coupled at a front end portion to the chuck. In a preferred embodiment, a push member is coupled at a front end to the lead case while a spring biases the inner mechanism rearwardly. A mechanism is provided for converting the relative rotation of the first and second members to axial movement of the inner mechanism between retracted and writing positions.

Abstract: A rotational slide type mechanical pencil having front and rear relatively rotatable bodies with a lead case disposed therein. A chuck which is rigidly coupled to the case firmly grips the lead in writing positions of the pencil. A chuck tightening member is provided having a chuck receiving portion which engages and tightens the chuck. A slider which is movable back and forth through a predetermined distance and is disposed forwardly of the chuck frictionally grips the lead. A conversion mechanism is provided for converting rotational movement of the rear axial body to linear movement of the chuck tightening member whereby the rotational movement of the second body moves the slider forwardly extending a portion of the slider through the front opening of an axial hollow body and extending the lead therethrough.

Abstract: A mechanical pencil in which the lead is advanced by squeezing a cylindrical depression member provided at the position of the writer's fingers during normal writing operations. The pencil includes a hollow body with front and rear axial sleeves. A chuck is disposed within the pencil body which has a resiliency which urges the chuck to open outwardly at the front end thereof. A slider including a lead holding member for lightly holding the lead is slidably positioned at the tip of the front axial sleeve. Means is provided for transmitting movement from the depression member, which is formed of a resilient material flush with the cylindrical surface of the pencil body, for transmitting movement from the depression member to the chuck. A lead casing means is disposed in the rear axial sleeve which in some embodiments has the dual function of transmitting movement from a push button provided at the rear of the pencil to the chuck for advancing the lead in a conventional manner.

Abstract: A plotting head for use in a drawing machine comprising a housing attached to said drawing machine; a lead holding means installed for vertical movement within said housing and having a vertical through hole; a bias means disposed above said lead holding means and imparting it a continuous descending tendency; a long cover means covering said bias means; a chuck means disposed for vertical movement in the through hole of said lead holding means, provided with a vertical lead inserting hole and having at the lower part a collet portion arranged to shut for clamping the lead and open for releasing the lead depending upon the vertical movement of said chuck means; a gripping means disposed for vertical movement on the bottom wall of said housing and operating to grip the top of the lead; and an actuating means operating to allow said lead holding means to ascend against the force of said bias means.

Abstract: A mechanical pencil including a buffer spring is disclosed. The mechanical pencil has a chuck whose chucking point is elongated in the direction towards the front of the pencil so that if the lead is broken at the chucking point, the length of broken lead within the pencil is minimized, thereby reducing the amount of wasted lead. The buffer spring is located either adjacent the fastening ring or within the lead case. In either embodiment, the buffer spring buffers the impact of the chucking point against the fastening ring. In the embodiment where the buffer spring is located within the lead case, the lead case and an intermediate connecting member, together with the distance therebetween, form a buffer spring operating mechanism.

Abstract: A mechanical pencil having a main hollow body including a first body member and a second body member with a mouth opening at an end and the first body member being rotatable with respect to the second body member and the first and second body members engaged with each other. A slider is retractable from the opening of the main hollow body and has a lead retainer for frictionally gripping lead and a lead case containing extra leads therein is disposed to the rear and is so biased. A lead gripping chuck is connected at the rear end thereof to said lead case and chuck tightening mechanism receives and tightens the chuck and advancing the chuck relative to the mechanism to supply a new lead having a predetermined length from the opening of the slider. The rotational movement of the first body member is transferred to reciprocating movement of the chuck tightening mechanism so that a new lead is supplied from the opening of the main hollow body by the rotation of the first body member.

Abstract: A press-out type writing tool having a holder body and a mechanism disposed in the holder body for pressing out pencil lead. The mechanism includes a depressing tube, a chuck for clamping the lead and a lead clamp. The lead clamp is formed separately from the chuck and is adapted to come in and out of an end opening of the holder body, while clamping the lead. The lead clamp projects out of the lower opening of the holder body, when the tool is used for the writing purpose, and is adapted to make up the required projection length of the lead as the latter wears. When the tool is not used, the lead clamp is retracted to disappear into the holder body, along with the lead which is clamped by the lead clamp, so as to protect the lead against any external force which may incur the breakage of the lead. The upper end of the lead clamp in the retracted state is received by an enlarged hole formed in the lower end of the chuck, so as to make the chuck release the lead.

Abstract: A mechanical pencil includes a casing, a chuck for holding a lead, a lead passage connected with the chuck, a lead cartridge and a push button for advancing the lead. A cylindrical body is connected to the lead passage. The cylindrical body and the lead cartridge have guides so that the both may be snuggly and accurately engaged with each other in accordance with the diameter of leads which are used in the pencil.

Abstract: A mechanical pencil of the type in which a lead is gripped in a collet clamped about the lead by engagement between cooperating conical faces of a clamping ring and respective movable ends of two elongated collet members which form the collet and pass through the ring. The collet members are connected together at their other ends. The pencil is readily disassembled and assembled because the movable ends, when in the clamping position, are shaped to interfit with the bore of the ring, so as to permit passage of the collet through the ring in one angular position of the collet relative to the ring while preventing such passage except for limited axial movement in another angular position. Cooperating guide elements on the collet and ring hold the collet in the another angular position. A tubular closure member is releasably fastened to the barrel, and in the another position the collet can be axially displaced relative to the ring when the closure member is released.

Abstract: A mechanical pencil having first and second rotatable body members and a slider mounted for retractable movement in one of the members. The slider has an axial retainer for frictionally gripping the lead. A lead case is disposed within one body member having a lead gripping chuck connected to one end. A chuck tightening mechanism advances and tightens the chuck to supply lead to the slider having a predetermined length. Rotation of the two body members relative to each other is translated into a corresponding movement to the chuck tightening mechanism. A resilient or magnetic member may be placed in the slider to maintain contact with the tightening mechanism.

Abstract: A lead-feeding mechanism comprising a lead reservoir, a connector, and a chuck in a mechanical pencil is held by a front spring in a normal rear position, at which the chuck is clamping a lead piece, but when a forward shake is imparted to the pencil, a weight collides forwardly with the lead-feeding mechanism and pushes the same forward, counter to the force of the spring, whereupon the chuck feeds the lead piece through a specific distance then releases the same, the lead-feeding mechanism being subsequently returned by the spring to the normal position, where the chuck again clamps the lead piece at a new position thereof.

Abstract: A mechanical pencil with a lead feed, automatically produced by pressure during use of the pencil, comprises a tubular lead magazine closed at an outer end by a removable actuating button and being movably guided in a tubular housing, clamping elements in the housing actuatable by pressure on the actuating button and a lead guide tube projecting from a conical end of the housing and being movable against the pressure of a spring into the latter and carrying at the inner end thereof an entrainment element exerting friction on the lead passing therethrough, in which the clamping elements are movable by means of the actuating button against the force of a second weaker spring and guided by rolling elements along a conical guide face of a clamping cone, which in turn is axially movable between two end positions in the housing.

Abstract: A writing instrument for thin lead refills comprising a housing and a lead feed mechanism located within the housing and wherein the feed of the lead refills is effected by a lead collet slidable axially against a spring force. The housing is sub-divided into front and rear housing sections which are axially adjacent one another and are relatively rotatable about a longitudinal axis of the instrument. To each housing section there is secured in rotation a component of a cam assembly comprising a thrust cam component and a thruster component. Upon relative rotation of the housing sections, the components interact with one another to slide the lead collet into projected open position for receiving a lead refill. One of the cam components is axially secured with the associated housing section and the other cam component is axially secured with the part of the lead feed mechanism carrying the lead collet and is axially displaceble with respect to the associated housing section.

Abstract: A writing instrument includes a holding outer tube to be held by the user and a lead rod holding means, said lead rod holding means being provided in said holding outer tube and movable relative to said outer tube. The writing instrument has a lead rod feeding means; an engaging member for holding said lead rod holding mechanism at a position where a lead rod guiding pipe engages with an engaging surface formed on said holding outer tube when said lead rod guiding pipe advances to a position projected from said holding outer tube by pressing said lead rod holding means; and a push button provided for pushing said engaging member to release the engagement with said surface.

Abstract: A mechanical pencil has an axially elongated hollow pencil body in which is slidable a tubular seat member. A lead-protecting sleeve is axially displaceable in the pencil body between a front position and a rear position and is urged into the front position with a relatively strong spring force. At least two jaws are axially displaceable on the seat and are moved radially closer as they move backwardly from the tip so as to grip a lead that projects backwardly from the lead-projecting sleeve. A relatively weak spring urges these jaws backwardly in the seat. An O-ring is provided in the lead-projecting sleeve so that each time the pencil tip is lifted from the writing surface the lead is automatically pulled forwardly by the strong spring force through the jaws. Similarly forward displacement of the seat in which the jaws rest allows for manual advance of a lead gripped by the jaws and passing through the lead-protecting sleeve.

Abstract: A mechanical pencil having a mouth piece 5 extendable and retractable in and out of the end portion 3 of a main body 1, and a tip sleeve 14 extendable and retractable in and out of the end portion of the mouth piece 5. The mouth piece is extendable or retractable by fully depressing a push cap 2, while the lead may be inched forward by partially depressing the push cap. The tip sleeve protects the lead, and is designed to automatically move inwardly in response to writing pressure, to thereby always expose the end of the lead for writing.

Abstract: A mechanical pencil, especially for thin leads, in which a tubular guide projects from and is guided for movement in axial direction in one end of a tubular casing. Lead is automatically advanced through the casing as a function of pressure exerted on the tubular guide during writing or drawing by successively compressing and expanding a tubular, resilient element having a conically-shaped end. During writing or drawing, the resilient element is compressed and its conically shaped end is wedged in tight engagement into a cooperating conically shaped end of an abutment member so as to clamp lead passing through the casing, thereby preventing the lead from moving inwardly during writing. When pressure is terminated, the resilient element is restored to its expanded condition, thereby freeing the lead to advance.