GB2180294A - Adjustable door closer - Google Patents

Abstract

A door closer has a piston (13, Fig. 1) slidably disposed in a cylinder (11) containing hydraulic fluid, the piston being moved in one direction against restoring means (28) upon opening of the door, and being moved in the opposite direction by the restoring means to close the door. Means are provided for altering the force of the restoring means, including a nut (24) screwthreadedly engaged on a screw (21) for movement therealong as the screw is rotated, such movement either increasing or decreasing the power of the restoring means, which are springs (28). The screw (21) non-rotatably carries a gear (35, Fig. 2) which has a gear tooth (35a) which can intermittently engage gear teeth (37) of a gear wheel (36) disposed in a recess in an end plug (32) of the closer. The gear wheel carries numerals and an end cover on the plug has a window (39) through which a different numeral is visible to correspond to different adjusted spring forces. <IMAGE>

Description

SPECIFICATION Improved door closer This invention relates to a door closer for fitting to a door or associatedframe and in which a piston is slidablydisposed in a cylinder containing hydraulic fluid, angular movement of the doorin one direction, in use, forcing the piston to move in one direction in the cylinder, such movementtaking place in oppositin to restoring means acting directly or indirectly on the piston, the restoring means directly or indirectly moving the piston in the opposite direction in the cylinder to effect angular movement ofthe door in the apposite direction. Such a doorcloserwill hereinafter be referred to as being of the kind specified.

The restoring means can be any form of means which stores energy as the-piston moves in said one direction, and releases such energyto cause the piston to move in the opposite direction. For example the restoring means could be ain which is compressed by hydraulicfluid as the piston moves in said one direction.

Usually, however, the restoring means is a spring.

The power ofthe spring is normally set during assembly and is not intended to be altered thereafter.

However for some applications the door closer can be provided with meanswh ich allowthe power of the spring to be adjusted on siteto suit local conditions.

Accordingly some means of indicating the relative power settings ofthe spring mustthen be provided.

The object ofthe invention isto provide an improved door closer ofthe kind specified, in which there are provided in a simple yet effective manner means for adjusting the power of the restoring means and indicator meansfor providing an indication of the relative powersettings.

According to the present invention a door closer of the kind specified comprises means for altering the force of the restoring means, actuation ofthe force altering means causing movement of indicator means to provide a visual indication ofthe force adjustment, the indicator means being integral with, or directly or indirectly connected to, the force altering means.

Preferably the force of the compression spring, which forms said restoring means, is adjusted by rotation of a screw, which carries a gearwheel engaged with a matchingly toothed indicator wheel.

The adjustment indication is provided by differing indicia on the indicator wheel becoming visible ata window as the indicator wheel is rotated ortraversed by rotation of the screw.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa longitudinal cross-sectional view of a door closer of the invention, Figure 2 is an enlarged cross-sectional viewof part of the door closer, Figure 3 is a cross-section on the line 3-3 of Figure 1, and Figure 4 is a view ozone end ofthe doorcloser.

The door closershown in Figure 1 is of conventional form comprising a casing 10, defining an internal cylindrical chamber 11,closed atone end byan end plug 12. Slidably disposed in the chamber 11 is a piston 13, which in the example illustrated is in the form of a rack with cylindrical ends 14, 15, respective ly, each being a close sliding fit in the cylinder. The rack is engaged by an associated pinion 16, which projects out ofthe casing 10 and is connected to lever arms, not shown, which are connected to a door or frame in the usual manner. Opening and closing ofthe door thus causes rotation ofthe pinion, and consequent linear movement of the piston in the cylinder.

The piston end 15 has a central circular hole 17 therethrough, in which is secured the end of a hollow, cylindrical tube 1 8. The tube is externally stepped with its narrower part engaged in the hole 17. A generally cylindrical rod 19 has one of its ends engaged in the tube 18 as a sliding fit. Its opposite end is stepped and threaded forengagementwith corresponding threads in a bore 20 in the end of a screw 21.A shank portion 22 ofthe screw 21 is externally threaded at 23 and receives thereon a nut 24 which has a circular external surface and is prevented from rotating upon rotation ofthe screw 21 by the provision of a rivet 25 punched into its periphery (Fig. 3), the rivet having a domed head 26 which is retained in a longitudinal groove 27 in the interior su rface of the cylinder. Rotation of the screw 21 thus causes movement of the nut 24 along the screw shank.

A bankofcompression springs 28 are disposed aroundthe rod 19 between the piston end 15 and the nut 24, which therefore act as respective stops against which the spring ends bear. Thus movement ofthe nut along the screw shank will result in compression or expansion ofthe springs 28 depending on the direction in which the screw isturned.

Rotation ofthe adjustment screw 21 to allow spring expansion is limited by engagement of the nut 24 against a collar 29 on an unthreaded part of the shank adjacent cylindrical head 30 ofthe screw. Rotation in the opposite direction is limited by the nut 24 engaging a stop in the form of a split spring ring and washer (not shown) secured onto the screw shank at the end ofthe screw 21 in which the bore 20 is provided.

The head 30 ofthe screw is received in a central bore 31 in a generally cylindrical end plug 32 which closes the end ofthe cylinder opposite to that closed bythe plug 12.A pair of annular seals 33 is carried on the screw 21 between the collar 29 and an inner face of the plug 32, and two O-ring seals 34 are provided in an annual recess in said innerface ofthe plug 32 to seal against the surface of the head 30. A peripheral groove in the external surface of each end plug receives a yet further seal which contacts the inner casing surface.

The cylindrical chamber 11 isthusfluidtightand contains hydraulic fluid in the usual manner. Passages are provided in the conventional mannerto allow the hydrauliefluid to flow from one side of the piston to the otherasthe doorisopened or closed and the piston reciprocates with the rod 19 sliding in the tube 18. The passages and valve arrangements for allowing full or restricted flow of hydraulic fluid are convention- alandastheyform nopartoftheinventiontheywill not be described.

The outer surface ofthe end plug 32 informed with an annular groove having its centre coincident with the centre ofthe bore 31 and communicating there with. In the outer surface ofthe end plug 32 there is also provided a circular recess of the same depth as the annulargroove,sothat it is aligned therewith, but off-centre with respect thereto, and a smaller diameter bore which breaks centrally into the recess. The position and radius ofthe circular recess is such that the recess just breaks intothe annular recess. The head 30 ofthe screw 21 extends just out ofthe bore 31 at the outerface ofthe plug 32 and interference fitted thereon for rotation therewith its a moulded gear 35 of plastics material.The gear is in the form of a ring having a single, radially directed geartooth 35a on its outer periphery, the tooth extending sufficiently from the ring to reach into the region of overiap ofthe groove and the recess.

In the recess, there is fitted a gearwheel 36 of metal or plastics with a rearspigotofthe gearfitting in the smaller diameter bore. The gearwheel has gearteeth 37 around its whole periphery, the gearteeth 37 matching the tooth 35a. Sincethe gearwheel 36 has the same centre as the recess and is of substantially identical diameter, some of the gearteeth 37 thus project into said overlap region and the tooth 35a engages intermittently between a pair ofthe teeth 37 upon rotation ofthe gear 35. Thus rotation ofthe screw 21, and thus the gear 35, causes rotation of the gearwheel 36.

The gearwheel 36 has numerals on its outer surface aranged radiallytherearound, and as the outer surface ofthe end plug 32 is disposed a little way inward ofthe end ofthe casing 10, a cover plate 38 can be glued to the outer surface of the end plug 32 so that its outer surface is flush with or slightly inward ofthe end ofthe casing 1 O.The cover plate thus securesthe gearwheel 36 in position in its recess. Awindow39 is provided in the cover plate, through which the numerals on the gearwheel 36 are visible as the gearwheel rotates, only one numeral being fully visible in any position of rotation. Thus a relative indication ofthe adjusted spring power is given by reference to the numeral visiblethrough the window.The relative diameters of the gear and gearwheel, and the arrangement of gear teeth are such that, for example, two rotations of the screw21 result in a change from one numeral appearing through the window to an adjacent numeral appearing. However more than one gear tooth could be provided on the gearwheel, in that the relative rotations between the members 35 and 36 can be differentfrom the described example.

On assemblythe indicating mechanism can beset so thatthe limits of spring power adjustment mentioned above correspond to the highest and lowest numerals appearing at the window 39. Once assem bled the screw rotation can be effected by the use of an Allen keyengaged in a corresponding hexagonal recess 40 in the end ofthe screw. To ensure smooth rotation ofthe gearwheel 36, it can be damped by providing frictional grease behind it.

Thus a simple yet effective power setting indicator is provided in the door closer. The positive mechanical connections between the nut power adjusting means, i.e. the nut which receivesspring pressure, and the indicating means, i.e. the gearwheel 36, ensures a sensitive, yet accurate and reliable visual indication.

Claims (13)

1. A door closer of the kind specified, comprising means for altering the force ofthe restoring means, actuation oftheforce altering means causing move ment of indicator means to piovide a visual indication ofthe force adjustment, the indicator means being integral with, or directly or indirectly connected to, the force altering means.

2. A door closer as claimed in claim 1, wherein the indicator means is a rotatable member sepa rate from the force altering means.

3. A door closer as claimed in claim 1 orclaim 2, wherein the indicator means is a gearwheel having gearteeth on its periphery

4. A door closer as claimed in claim 3, wherein the force altering means includes a rotatable adjustment memberwith a gear thereon, the gear having at least one geartooth which can engage with the gear teeth ofthegearwheel,sothatrotation oftheadjustment member causes rotation of the indicator means.

5. Adoorcloseras claimed in claim 4, wherein the adjustment member is a screw, one end of which projects through the centre of a plug which closes one end ofthe door closer, said end of the screw having said gear non-rotatablythereon, the gear being received in an annular groove in an outwardly facing surface of said plug,the gearwheel being rotatably disposed in a circular recess in said outwardly facing plug surface, the recess and groove having a common region of overlap where the gear teeth engage

6. Adoor closer as claimed in claim 5, wherein said outwardlyfacing plug surface has a cover plate thereon, a window being provided in the cover plate, the gearwheel having markings thereon which are successively visible through said window as the gear wheel is rotated upon actuation ofthe force altering means, so thatthe marking visible at anytime provides an indication ofthe relative adjustment ofthe force ofthe restoring means.

7. A door closer as claimed in claim 6, wherein the gear has a single geartooth and the gear and rear wheel are so arranged that two rotations of the adjustment member and thus ofthe gear, result in a change from one marking to the next being visible through said window.

8. A door closer as claimed in any one of the preceding claims, wherein the force altering means includes a rotatable adjustment member which carries a force transmitting member, rotation ofthe adjustment member causing the force transmitting memberto move relative thereto to cause compression or allow expansion ofthe restoring means, thereby altering the force thereof.

9. A door closer as claimed in claim 8, wherein the rotatable adjustement member is a screw and the force transmitting member is screwthreadedly en- gaged thereon and prevented from rotating, so that rotation ofthe screw causes linear movement of the force transmitting movement along the screw.

10. Adoorcloseras claimed in claim 9,wherein the force transmitting member has a projection extending from its periphery into a longitudinal groove in the interior ofthe cylinderto prevent it rotating upon rotation of the screw and to effect movement along the screw.

11. Adoorcloser as claimed in claim 8 or 9, wherein the restoring means acts between the force transmitting member and the piston, and comprises one or more springs.

12. Adoorcloseras claimed in claim 6,wherein thecoverplate has its outerflushwith or slightly inward ofthe end of the door closer, said one end of the screw projection into a central hole in the cover plate and having a recess therein for engagement by an adjustment tool for rotating the screw to adjust the forceofthe restoring means.

13. A closer substantially as hereinhefore de scribedwith referencetoand as shown inthe accompanying drawings.