[go: up one dir, main page]

CH387569A - Vorrichtung zur Betätigung eines Arbeitsorganes durch ein unter Druck stehendes Strömungsmittel und Verwendung der Vorrichtung - Google Patents

Vorrichtung zur Betätigung eines Arbeitsorganes durch ein unter Druck stehendes Strömungsmittel und Verwendung der Vorrichtung

Info

Publication number
CH387569A
CH387569A CH7831759A CH7831759A CH387569A CH 387569 A CH387569 A CH 387569A CH 7831759 A CH7831759 A CH 7831759A CH 7831759 A CH7831759 A CH 7831759A CH 387569 A CH387569 A CH 387569A
Authority
CH
Switzerland
Prior art keywords
actuating
under pressure
fluid under
working organ
organ
Prior art date
Application number
CH7831759A
Other languages
English (en)
Inventor
George Juilfs Albert
Original Assignee
Senco Products
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Senco Products filed Critical Senco Products
Publication of CH387569A publication Critical patent/CH387569A/de

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25C—HAND-HELD NAILING OR STAPLING TOOLS; MANUALLY OPERATED PORTABLE STAPLING TOOLS
    • B25C1/00—Hand-held nailing tools; Nail feeding devices
    • B25C1/04—Hand-held nailing tools; Nail feeding devices operated by fluid pressure, e.g. by air pressure
    • B25C1/041—Hand-held nailing tools; Nail feeding devices operated by fluid pressure, e.g. by air pressure with fixed main cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/421—Flow control characterised by the type of actuation mechanically
    • F15B2211/424—Flow control characterised by the type of actuation mechanically actuated by an output member of the circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/625—Accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/72—Output members, e.g. hydraulic motors or cylinders or control therefor having locking means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/77—Control of direction of movement of the output member
    • F15B2211/7716—Control of direction of movement of the output member with automatic return
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S91/00—Motors: expansible chamber type
    • Y10S91/04—Magnets

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Portable Nailing Machines And Staplers (AREA)
CH7831759A 1959-04-27 1959-09-17 Vorrichtung zur Betätigung eines Arbeitsorganes durch ein unter Druck stehendes Strömungsmittel und Verwendung der Vorrichtung CH387569A (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US809129A US2983922A (en) 1959-04-27 1959-04-27 Portable stapler with pneumatic drive and return

Publications (1)

Publication Number Publication Date
CH387569A true CH387569A (de) 1965-01-31

Family

ID=25200606

Family Applications (1)

Application Number Title Priority Date Filing Date
CH7831759A CH387569A (de) 1959-04-27 1959-09-17 Vorrichtung zur Betätigung eines Arbeitsorganes durch ein unter Druck stehendes Strömungsmittel und Verwendung der Vorrichtung

Country Status (3)

Country Link
US (1) US2983922A (de)
BE (1) BE582426A (de)
CH (1) CH387569A (de)

Families Citing this family (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3087160A (en) * 1960-07-25 1963-04-30 Alvin Doppelt Stapling machine
DE1204599B (de) * 1961-01-13 1965-11-04 Behrens Friedrich Joh Stoesselfuehrung fuer Geraete zum Eintreiben von Heftklammern od. dgl.
DE1225120B (de) * 1961-03-15 1966-09-15 Behrens Friedrich Joh Mit Druckluft betriebenes Geraet zum Eintreiben von Befestigungsmitteln, z. B. Naegeln oder U-foermigen Klammern
US3147670A (en) * 1961-05-10 1964-09-08 Herman J Spencer Valve and other apparatus
DE1253196B (de) * 1961-06-29 1967-10-26 Behrens Friedrich Joh Mit Druckluft betriebenes Geraet zum Eintreiben von Befestigungsmitteln wie Klammern, Naegeln u. dgl.
US3101476A (en) * 1961-09-11 1963-08-27 Fastener Corp Fastener driving apparatus
DE1274524B (de) * 1962-02-17 1968-08-01 Haubold Dieter Mit Pressluft betriebenes Geraet zum Eintreiben von Befestigungsmitteln, insbesondere Klammern
US3181428A (en) * 1962-03-06 1965-05-04 Bukama G M B H Pneumatic fastener device
US3251276A (en) * 1962-05-25 1966-05-17 Volkmann Dieter Stapling machine
US3160075A (en) * 1962-06-22 1964-12-08 Powers Wire Products Company I Cylinder and self return piston with lubrication means
DE1246622B (de) * 1962-07-06 1967-08-03 Haubold Dieter Mit Pressluft betriebenes Geraet zum Eintreiben von Klammern, Naegeln und aehnlichenBefestigungsmitteln
US3216327A (en) * 1962-09-28 1965-11-09 John R Johansson Device for hydraulically or pneumatically controlling reciprocating movements of an operative means
US3193167A (en) * 1963-06-13 1965-07-06 United Shoe Machinery Corp Hand tools for installing tacks and the like
NL6415071A (de) * 1964-12-24 1966-06-27
DE1285959B (de) * 1964-12-28 1968-12-19 Behrens Friedrich Joh Druckluftbetaetigtes Geraet zum Eintreiben von Naegeln, Heftklammern od. dgl.
DE1478928A1 (de) * 1965-02-04 1969-06-04 Dieter Haubold Ind Nagelgeraet Steuerventileinrichtung fuer ein mit Druckluft betriebenes Geraet zum Eintreiben von Befestigungsmitteln
US3313213A (en) * 1965-05-20 1967-04-11 Fastener Corp Fastener driving tool
US3363517A (en) * 1965-09-16 1968-01-16 Powers Wire Products Co Inc Air return percussive tool
DE1478933A1 (de) * 1965-10-27 1969-06-04 Dieter Haubold Ind Nagelgeraet Mit Pressluft betriebenes Geraet zum Eintreiben von Befestigungsmitteln
GB1172224A (en) * 1965-12-29 1969-11-26 Gaston E Marbaix Ltd Improvements relating to Pneumatic Devices for Driving Fasteners or like purposes
US3362602A (en) * 1966-02-28 1968-01-09 Powernails Inc Nailing machine
US3329068A (en) * 1966-04-15 1967-07-04 Signode Corp Pneumatic piston return system for impact tools
US3400637A (en) * 1966-08-08 1968-09-10 Trico Products Corp Fluid pressure power unit with magnetic latching means
US3477629A (en) * 1966-11-23 1969-11-11 Senco Products Pneumatic fastener applying device
US3567098A (en) * 1966-12-23 1971-03-02 Bostitch Div Of Textron Fastener driving apparatus operable under pressure conditions greater than line pressure
DE1301767B (de) * 1967-01-28 1969-08-21 Behrens Friedrich Joh Entlueftungseinrichtung fuer den fussseitigen Zylinderraum eines druckluftbetaetigten Schubkolbenantriebes fuer Heft- oder Nagelgeraete
DE1301766B (de) * 1967-02-01 1969-08-21 Behrens Friedrich Joh Dauermagnetische, den Arbeitskolben eines druckluftbetaetigten Geraetes zum Eintreiben von Klammern, Naegeln od. dgl. in der oberen Totpunktlage haltende Haltevorrichtung
US3580435A (en) * 1968-04-15 1971-05-25 Atlas Copco Ab Spray gun with pressure operated valve
DE1801162A1 (de) * 1968-10-04 1970-04-16 Dieter Haubold Ind Nagelgeraet Mit Druckluft betriebenes Schlaggeraet,insbesondere Heft- oder Nagelgeraet
US3645170A (en) * 1969-08-01 1972-02-29 Theodore A Varouxis Air cylinder with self-contained pneumatic piston return
US3760695A (en) * 1972-03-01 1973-09-25 Senco Products Resilient piston stop construction
DE2339163C2 (de) * 1973-08-02 1975-01-30 Karl M. Reich, Maschinenfabrik Gmbh, 7440 Nuertingen Schlagpuffer für Einschlaggeräte
US3999465A (en) * 1974-11-01 1976-12-28 Clark Equipment Company Magnet piston retention for free wheeling
DE3603992A1 (de) * 1986-02-08 1987-08-20 Bosch Gmbh Robert Arbeitszylinder mit einem elektrischen kolbenendstellungsgeber
JPH01257578A (ja) * 1988-04-01 1989-10-13 Hitachi Koki Co Ltd 打込機
US5181450A (en) * 1991-05-16 1993-01-26 Umberto Monacelli Pneumatic fastener driving apparatus with piston holding detent
EP0684108A1 (de) * 1994-05-20 1995-11-29 Umberto Monacelli Eintreibgerät für Befestigungselemente mit pneumatischem Antrieb
US5860580A (en) * 1996-05-03 1999-01-19 Illinois Tool Works Inc. Piston retention device for combustion-powered tools
US6779698B2 (en) * 2001-10-15 2004-08-24 Hwai-Tay Lin Abrasion-resistant bumper for a nail-driving tool
DE10253670B4 (de) * 2002-11-19 2021-05-06 Hilti Aktiengesellschaft Brennkraftbetriebenes Setzgerät
US7708178B2 (en) * 2005-03-07 2010-05-04 Carroll Bassett Handheld pneumatic tool for breaking up rock
US9662777B2 (en) * 2013-08-22 2017-05-30 Techtronic Power Tools Technology Limited Pneumatic fastener driver
US11110577B2 (en) 2017-11-16 2021-09-07 Milwaukee Electric Tool Corporation Pneumatic fastener driver
AU2021216036B2 (en) * 2020-02-05 2023-12-07 Kyocera Senco Industrial Tools, Inc. Gas spring fastener driving tool with fill valve located in an end cap

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1014639A (en) * 1910-11-26 1912-01-16 William Evans Colwell Pneumatic hammer for driving nails.
US2682052A (en) * 1953-04-03 1954-06-29 Albert G Juilfs Plunger and staple driving structure for pneumatic stapling machines
DE1025349B (de) * 1954-09-18 1958-02-27 Reich Maschf Gmbh Karl Mit Druckluft betriebene Vorrichtung zum Einschlagen von Naegeln od. dgl.
US2807021A (en) * 1955-02-10 1957-09-24 United Shoe Machinery Corp Fluid motors of the percussive type
DE1043974B (de) * 1955-07-12 1958-11-13 Reich Maschf Gmbh Karl Mit Druckluft betriebene Vorrichtung zum Einschlagen von Naegeln od. dgl.

Also Published As

Publication number Publication date
BE582426A (fr) 1960-12-31
US2983922A (en) 1961-05-16

Similar Documents

Publication Publication Date Title
CH387569A (de) Vorrichtung zur Betätigung eines Arbeitsorganes durch ein unter Druck stehendes Strömungsmittel und Verwendung der Vorrichtung
CH390490A (de) Vorrichtung zum Möblieren eines Raumes
CH364224A (de) Vorrichtung zum Belüften von unter Druck fliessendem Wasser
CH404701A (de) Verfahren zur Kühlung eines Fluidums und Vorrichtung zur Durchführung des Verfahrens
CH363676A (de) Vorrichtung zur Durchführung eines Verfahrens zur Herstellung von Schlüsselfolgen sehr grosser Periode
CH326271A (de) Steuerverfahren für einen Kolbenschieber einer Schlammzentrifuge und Einrichtung zur Durchführung des Verfahrens
CH402115A (de) Steuerschalter zur Überwachung eines Gasdruckes
CH380441A (de) Vorrichtung zum Einspritzen eines flüssigen oder gasförmigen Mittels unter Druck in ein Medium
CH366069A (de) Vorrichtung zur Umwandlung eines Impulssignales in ein hasenmoduliertes Signal
CH335881A (de) Vorrichtung zur Regelung des Drucks eines flüssigen oder gasförmigen Mediums
CH381771A (de) Halbleiterbauelement mit einer gasdichten Kammer sowie Verfahren zur Herstellung eines solchen Halbleiterelementes und Vorrichtung zur Durchführung des Verfahrens
CH364464A (de) Vorrichtung zum Abgeben eines fliessfähigen Materials durch Dampfdruck
CH350814A (de) Vorrichtung zur Herstellung eines reproduzierbaren symmetrischen Spaltes, insbesondere bei Spektrographen
CH399102A (de) Ventilanordnung zur Durchflusskontrolle von unter Druck stehendem Druckmittel
AT220191B (de) Vorrichtung zum Versprühen von Flüssigkeit mittels Druckluft
CH335244A (de) Verfahren zum Eintreiben von Verankerungsbolzen in Bauteile durch den Druck hochgespannter Gase
CH381171A (de) Vorrichtung zur Erzeugung eines Flüssigkeitsnebels
CH391948A (de) Vorrichtung zur Erzeugung statischen Druckes mittels einer Querstrompumpe für Flüssigkeiten oder Gase
CH393205A (de) Vorrichtung zum Belüften von unter Druck fliessendem Wasser, insbesondere für Haushaltszwecke
CH345358A (de) Vorrichtung zur geregelten Entnahme eines verflüssigten Gases aus einem Druckbehälter
CH376081A (de) Vorrichtung zur Regelung der Beschwerungsaufnahme eines Faserstoffes
CH349623A (de) Verfahren und Vorrichtung zur Steuerung eines Anfahr-Schnellschlussventils
CH388662A (de) Verfahren und Vorrichtung zur Kontrolle von Prüfeinrichtungen, die zur Ermittlung der mittleren Abweichung des variablen Querschnittes eines Prüflings von seinem Mittelwert dienen
CH385911A (de) Durch ein unter Druck stehendes Strömungsmittel betätigte Bremsvorrichtung
AT246014B (de) Verfahren zur Herstellung eines Ventilsackes