# US 2010/0167231 A1 · Piston and handheld dispenser including a piston > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167231 A1 - Document ID: US20100167231A1 - Status: Published application - Kind: A1 - Application number: 12/514,105 - Filed: 2007-11-21 - Published: 2010-07-01 - Earliest claimed: 2006-11-24 - Inventors: John W. Dubbe; Gioacchino Raia; Hecht Reinhold; Manfred Ludsteck; Bruce R. Broyles; Henry C. Gydesen; Dirk Albrecht; Helmut Pauser - Web page: https://patentgrep.com/patent/US20100167231A1 ## CPC - B05C 17/00576: {characterised by the construction of a piston as pressure exerting means, or of the co-operating container} - A61C 5/62: Applicators, e.g. syringes or guns - A61C 5/66: Capsules for filling material - B05C 17/012: {Stepwise advancing mechanism, e.g. pawl and ratchets} - A61C 5/64: for multi-component compositions - A61M 5/19: having more than one chamber - A61M 5/31513: {Piston constructions to improve sealing or sliding} - A61M 5/31515: {Connection of piston with piston rod} - A61M 5/31581: {the component being manually operated or triggered by a rotating or pivoting actuator operated by user, e.g. an injection lever or handle} - A61M 5/31593: {Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir} - B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08) - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract The invention includes a piston having a piston body (1) and front seal for sealing the gap between the side wall of the piston body and the wall of a chamber within which the piston and a material are disposed in a conventional manner. The front seal (5) has a leading edge (6) included angle (A) as defined below, and a trailing edge (7) included angle (B) that is smaller than the leading edge included angle. By the appropriate selection of these two angles, the force required to move the piston (and thus the material) is optimized, the force required to move the piston (and thus the material) is optimized, which results in a more useful dispenser than conventional syringe-type dispensers. These and other features of the present invention are described in greater detail below. ## Claims ### Claim at position 1 -35. (canceled) ### Claim 36 A piston for use in expelling a material from a chamber, comprising: (a) a piston body having a side wall; and (b) a front seal for sealing a gap between the side wall of the piston body and a wall of the chamber, wherein the front seal comprises an annular ridge having a generally “V” shaped profile tapering off to the outer periphery of the seal, and has a leading edge included angle, and a trailing edge included angle that is smaller than the leading edge included angle, the leading and trailing edge included angles being measured relative to the side wall of the piston, wherein the leading edge corresponds to the flank of the “V” shaped part of the front seal profile that is adapted to face the material in the chamber, and the trailing edge is the edge opposite to the leading edge adapted to face away from the material in the chamber, and the leading edge included angle is approximately 60 degrees, and the trailing edge included angle is approximately 55 degrees. ### Claim 37 (depends on 36) The piston of claim 36 wherein the piston further comprises a rear seal for sealing a gap between the side wall of the piston body and a wall of the chamber, wherein the rear seal has a leading edge included angle and a trailing edge included angle, and the trailing edge included angle is between about 70 degrees and 90 degrees. ### Claim 38 (depends on 37) The piston of claim 37, wherein the trailing edge included angle of the rear seal is approximately 90 degrees. ### Claim 39 The piston of any of the preceding claims, wherein the piston is made of low-density polyethylene (LDPE), and has a Shore D hardness of between 85 and 95. ### Claim 40 The piston of any of the preceding claims, wherein the front seal projects from the side wall of the piston body by between 0.8 mm and 1.4 mm. ### Claim 41 The piston of any of the preceding claims, wherein the piston comprises a coaxial pin protruding from the piston front. ### Claim 42 The piston of any of the preceding claims, in combination with a dispenser cartridge that includes the chamber. ### Claim 43 (depends on 42) The combination of claim 42, wherein the chamber includes a material with a viscosity of between 30 and 1500 Pa s. ### Claim 44 (depends on 43) The combination of claim 43, wherein the material is a dental material. ### Claim 45 (depends on 36, 37, 38, 39, 40, 41) A device for expelling a material, comprising: (a) a cartridge having a chamber for containing the material, and an opening through which the material may be expelled; and (b) a piston according any of the claims 36 to 41 adapted for insertion into and reciprocal movement within the chamber. ### Claim 46 (depends on 45) The device of claim 45, further comprising a plunger adapted for advancing the piston, and wherein the plunger comprises a ratchet, and the device comprising an actuator system for advancing the plunger, and wherein the actuator system comprises an advancing mechanism and a stop, and wherein the actuator system further comprises a lever for manual actuation of the advancing mechanism, and wherein the advancing mechanism is adapted to alternately move a pawl in forward and return strokes for stepwise moving the plunger forward during the forward strokes. ### Claim 47 (depends on 46) The device of claim 46, wherein the advancing mechanism provides for: (i) the pawl being in engagement with the ratchet of the plunger during the forward strokes, and for (ii) the pawl being in disengagement from the ratchet of the plunger during the return strokes. ### Claim 48 (depends on 46, 47) The device of claim 46 or 47, wherein the actuator system provides for: (i) the stop being in engagement with the ratchet of the plunger at the end of a return stroke, and for (ii) the stop being in disengagement from the ratchet during the major part of the forward and the return strokes.