Improvements in or relating to valves

Abstract: A valve (10) for use with a door closer comprises a body part (11) and a stem part (12), the body part having a threaded portion (13) and the stem part being coupled to the body part and having a valve seat at one of its ends. In one form, the stem part (12) is formed of a material having a thermal coefficient of expansion greater than the thermal coefficient of expansion of the door closer and is in snap-fitting engagement with the body part (11). In another form, the stem part (12) includes a yieldable portion (24) in the form of a reduced diameter rod co-axially connecting a pair of frusto-conical sections (22, 23) at its respective opposite ends.

Description: This invention relates to an improved hydraulic door closer comprising a valve in a fluid flow passage thereof for controlling fluid flow past an associated valve seat therein. U. S. Patent specification No. 4,148,111 discloses a hydraulic door closer in which in a flow return passage thereof is disposed a valve member which co-operates with a valve seat to control the damping effect of the hydraulic fluid as the door closes under the influence of the closer return spring. The valve is adjustable towards and away from its associated valve seat to vary the rate of fluid flow past said seat. Moreover to compensate for changes in the temperature of the hydraulic fluid, which can result in its 'thickening' or 'thinning', i.e. an increase or decrease in its viscosity, the valve is formed as a first portion of relatively dimensionally stable material, and a second portion of material of greater coefficient of thermal expansion. The first portion is typically of metallic material, such as steel, as it is exteriorally screw-threaded for engagement with a complementary interior screw-thread of the flow return passage, whilst the second portion is typically of plastics material such as nylon. The two portions are an interference fit together to provide, in effect, a one-piece composite valve. With similar types of thermo-compensating valves, the two portions are insert moulded together, to form the one-piece composite valve. U.S. Patent specification No. 4 573 238 discloses a door closer device incorporating a temperature compensating valve in which a first part is adjustably screw-threadedly engaged in a bore of the door closer body and is snap-fittingly engaged with a valve member part which is movable between two extreme positions relative to the first part, according to claim 1, first part. One disadvantage of these known one-piece composite valves is that they are each specifically for use with a particular form of flow passage and valve seat, so that little, if any, inter-changeability of elements is possible. A further more general disadvantage of this type of restrictor/regulator valve, whether of integral or of composite one-piece form, is the possibility that when it is screw-threadedly engaged in the flow passage, vibration/temperature/pressure can cause it to move angularly in its associated interior screw-thread formed in the passage, and thus self-adjust. This changes the closing time characteristic of the closer and thus necessitates more frequent maintenance of the door closer than would otherwise be necessary. An object of the invention is to provide an improved door closer. According to the present invention there is provided a door closer containing a temperature compensating valve, the valve comprising a body part having a threaded portion thereon, and a stem part in snap-fitting engagement with the body part, the stem part having a valve seat at an end thereof, and an elongated extension portion having a means thereon for retaining the stem part in snap-fitting engagement with the body part, the stem part being formed of a material having a thermal coefficient of expansion greater than the thermal coefficient of expansion of the door closer, characterised in that the threaded portion of the body part includes a non-threaded groove portion in which the elongated extension portion engages. The invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a side view of a valve of a door closer of one embodiment of the invention, and Figure 2 is a similar view to Figure 1, but at 90° thereto. The door closer of the present invention has a valve which is part of a restrictor/regulator arrangement in a flow passage in a body of the hydraulic door closer device. As is well known with such a device, hydraulic fluid is forced from one side of the spring loaded piston within the body to the other side thereof upon opening of the door, with the spring being compressed, the hydraulic fluid flowing in the opposite direction as the door closes and the spring returns the piston to its rest position. To ensure that the door closes at an acceptable rate, a flow passage between the chambers at respective opposite sides of the piston is normally provided with an adjustable valve which is operatively associated with a valve seat, so that the rate of closing of the door can be increased or decreased as required by angularly adjusting the valve so that fluid flow between said valve and said valve seat is increased or reduced as required. Accordingly as such a form of closer is well known, this will not be described or illustrated, it being therefore understood that the valve shown in Figures 1 and 2 is intended to perform the usual function of such a valve in said closer. The Figures show a valve 10 of elongated form, the valve being made up of two main parts, namely a relatively short externally screw-threaded body part 11 and an elongated stem part 12. As will be described hereinafter, the two parts are snap-fitted together and extend generally along a common axis. The body part 11, which is made of a relatively dimensionally stable structural material, normally a metallic material, such as steel, has a cylindrical centre portion 13 which is externally screw threaded as indicated by the numeral 14. Extending co-axially from one end of the portion 13 is an elongated stem portion or spigot 15 which is generally cylindrical, but has a frusto-conical free end section 16. Extending from the other end of the portion 13 is a head 17 which defines an annular groove 18 in which is fitted an O-ring seal 19 to seal the valve 10, in use, in its associated fluid flow passage. The free extremity of the head is slotted, as shown at 20, for engagement, in use, by a blade or the like in order to move the valve 10 angularly in its flow passage so as to adjust the position of the inner extremity of the valve 10 relative to its associated valve seat, as will be described hereinafter. The screw-thread 14 is interrupted through the whole of its longitudinal extent by a rectangular groove portion or channel 21 which extends longitudinally, and generally in the axial direction of the body part 11 as shown best in Figure 2. The depth of the channel is such that its base substantially forms a continuation of the adjacent part of the exterior surface of the spigot 15. A circular recess 32 is formed in the channel 21 at the end of the screw thread where it is adjacent the head 17. In one example, the channel 21 extends for approximately 45° of arc, but this is not critical. The part 11 alone is utilisible as a valve, with its spigot 15 being equivalent to stem part 12 of the two-part element. The stem part 12 is made of a material having a substantially greater coefficient of linear expansion than the material of the body of the door closer in which the valve 10 is to be used. Normally this will also be a greater coefficient of linear expansion than the material from which the body part 11 is made. Normally the stem part 12 would be made of plastics material, such a nylon. The stem part 12 is formed with a pair of coaxial, spaced frusto-conical sections 22, 23 respectively, between which is a reduced diameter circular-section co-axial yieldable rod portion 24, each of the sections 22, 23 increasing in diameter in a direction away from the rod portion 24. The section 23 extends to a mirror-image frusto-conical valve seat section 25 which thus correspondingly decreases in cross-section to its extremity which constitutes the free end of the part 12 and thus of the valve 10, the section 25 being that which co-operates, in use, with the associated valve seat of the passage in which the valve 10 is received. As shown in the drawings, the junction of the sections 23 and 25 can be provided with a plurality of equi-angularly spaced projecting feet 26 therearound. The section 22 terminates at a matching diameter hollow cylindrical portion which is in fact cut away around approximately 180° to leave a semi-cylindrical portion 27 extending from the larger diameter end of the section 22, the portion 27 extending in the general longitudinal axial direction of the stem part 12. The length of the portion 27 is just slightly greater than the length of the spigot 15, with the internal diameter of the portion 27 being dimensioned relative to the external diameter of the spigot so that, as will be described, in use, the spigot can be snap-fitted into engagement within the portion 27, as shown best in Figure 1, the material of the stem part 12 being resilient, as previously described. At the end of the portion 27 remote from the section 22, there projects an arm 28, this being disposed at the centre of the outer periphery of the portion 27, i.e. at approximately 90° around its outer surface from either free edge thereof. The arm 28 is rectangular in plan, as shown best in Figure 2 and is of a width, depth and length to enable it to engage snugly in the channel 21 which interrupts the screw-thread 14, the arm being disposed, as shown in Figure 1, in a plane slightly beyond that containing the surface of the portion 27 from which it extends. As shown in Figure 1, the arm is disposed in the channel 21 so that its outer surface is substantially flush with the outer surface of the screw threads at opposite sides of the channel 21. At the free end of the arm 28 an inwardly directed projecting circular spigot 29 is received within the circular recess 32 so as to enhance the fitting together of the body part 11 and the stem part 12, and resist any longitudinal separation between parts 11 and 12. A plurality of equi-angularly spaced feet 30, identical to feet 26, are provided at the junction of the section 22 and portion 27. In use, the valve 10 is fitted in a fluid flow passage machined into the body of a conventional hydraulic door closer device. At one end of the passage there is a conventional valve seat, whilst at its outer end, the passage is stepped to accommodate the head as a sealing fit, with part of the passage inwards of the step being internally screw threaded to complement the screw-thread 14 on the body part 11, so that insertion of the valve 10 involves screwing it into the passage formed in the body of the door closer by engagement of the threads 14 with the internal thread in the passage. As will be appreciated, the extent to which the valve 10 is screwed into the passage will determine the separation of the valve seat section 25 from the aforementioned valve seat, and thus the degree of restriction/regulation to flow which the valve 10 provides. As mentioned, the valve is adjustable axially by rotating it, this being effected by a blade or the like being engaged in the slot 20. Suitable indication means can be provided at the exterior of the flow passage to show which way the valve should be turned to decrease or increase flow and thus similarly to speed up or slow down the rate of closure of the door respectively. The feet 26 and 30 help to guide the valve, particularly to guide the part-conical section 25 onto its seat and assist concentricity in section 22 and portion 27, by providing location in the machined drilling in the body in which the valve is received. As described, two main parts of the valve are made of respective materials having different co-efficients of linear expansion, with the stem part 12 being of material having a greater coefficient of linear expansion than the body of the door closer. This is advantageous, in that the described difference in co-efficients of linear expansion will compensate for changes in the ambient temperature, so that a consequent change in the viscosity of the oil or other hydraulic fluid flowing in the flow passage will be compensated for, in the normal well known manner, so that there is automatic, self-adjustment rather than it being necessary manually to adjust the valve to compensate for temperatures changes. As is thus well known, a rise in the ambient temperature which will 'thin' or increase the viscosity of the oil is compensated for by expansion of the material of the stem part 12 so as to decrease the spacing between the stem part 12 and the valve seat. Similarly for decreasing temperatures, the 'thickening' or decrease in viscosity of the oil will be compensated for by corresponding contraction of the material of the stem part 12 so that the spacing between the stem part 12 and the valve seat will increase in order to maintain the oil flow constant as set by the previous manual adjustment of the valve 10. The snap-fit connection between the two main parts is not only more commercially viable than insert moulding as is the current practice in the door closer industry, but it also enables the valve 10 to be adapted as required for different thermal-compensation arrangements merely by changing the snap-on stem part in respect of material and/or size in order to suit differing thermal valve requirements. Thus this arrangement provides the interchangeability which, as mentioned in the introduction, is missing where the valve is formed of two parts which are permanently secured together or which are, in any event, not normally intended for separation. An advantage of the invention is provided by the interruption of the screw thread by the arm 28 of the stem part 12. This arm acts as a lock when the body part 11 threadingly engages with the interior threads in the flow passage of the door closer, with the result that transmission of vibration, movement or the like from the body of the closer to the body part 11 is reduced or eliminated. Accordingly the possibility of such vibration or movement causing self-adjustment of the body part 11, and thus the valve 10, during operational conditions is thus correspondingly reduced or eliminated, thus resulting in low maintenance. Finally the provision of the mid-section of the stem part 12 in the form of a yieldable reduced diameter rod provides a degree of vandal-proofing. With known valves in door closers, which valves are of rigid plastics, a slow taper will be forced to lock into its seat if the valve is forced home, i.e. over-adjusted, by keeping it concentric, usually resulting in the valve being sheared off in the closed position as more force is channelled into the end taper area. With the embodiment described, the mid-section, namely the yieldable portion 24, cripples if the valve is overtightened onto its valve seat so that the valve is not 'locked' in its closed position. This is because when the portion cripples, i.e. distorts, it mis-aligns the section 25, such axial displacement helping to prevent said section locking into its seat. Accordingly the door closer incorporates a valve which is advantageous both by way of its interrupted screw-thread construction, in providing an antivibration transmission, and also by a part of the valve stem automatically being engaged correctly in position when a snap-fit takes place between the two valve components.

Claims: A door closer containing a temperature compensating valve (10), the valve (10) comprising a body part (11) having a threaded portion (13) thereon, and a stem part (12) in snap-fitting engagement with the body part, the stem part (12) having a valve seat at an end thereof, and an elongated extension portion (27) having a means (28) thereon for retaining the stem part (12) in snap-fitting engagement with the body part (11), the stem part (12) being formed of a material having a thermal coefficient of expansion greater than the thermal coefficient of expansion of the door closer, characterised in that the threaded portion (13) of the body part (11) includes a non-threaded groove portion (21) in which the elongated extension portion (27) engages. A door closer as claimed in Claim 1, wherein said means (28) on the elongated extension portion (27) is an arm having a projection (29) received in a recess (32) in the groove portion (21).

Inventors: LUCKETT NICHOLAS GEORGE, LUCKETT, NICHOLAS GEORGE
Applicants: IR SECURITY & SAFETY LTD, IR SECURITY & SAFETY LIMITED
Application year: 1998
Main classification: E05F3
IPC codes: E05F3