Door closer

Abstract

 An apparatus (10) is described for controlling angular movement of a door (11), the apparatus (10) including a housing (17) and a piston (20), having a longitudinal axis (22), slidable in a cylinder (18) in the housing (17). The piston (20) has a transverse opening (24) therethrough, with an inwardly facing wall (26) of the opening (24) provided with a rack gear (28) having a plurality of teeth (29) which are substantially transverse to the longitudinal axis (22) of the piston (20). The apparatus (10) also includes a pinion gear (30) supported for rotation about its longitudinal axis (34) by the housing (17) and extending through the transverse opening (24) in the piston (20), the pinion gear (30) having a plurality of teeth (32) which engage with the teeth (29) of the rack gear(28), such that rotation of the pinion gear (30) about its longitudinal axis (34) effects sliding movement of the piston (20) through the cylinder (18). A top land of each tooth (32) of the pinion gear (30) has two portions (53, 54) each of which extends towards the longitudinal axis (34) of the pinion gear (30) at a homogenous gradient as it extends away from the other side portion (53, 54). Alternatively, the top land of each tooth (32) of the pinion gear (30) has a substantially central portion (52), which is substantially parallel to the longitudinal axis (34) of the pinion gear (30), and is provided between the two side portions (53, 54).

Description

[0001] This invention relates to an apparatus for controlling angular movement of a door.

[0002] Such apparatuses are well known in the art and are commonly known as "door closers". They typically include a piston slidably mounted in a cylinder in a housing, which housing is connectable to an upper part of a door. The piston has a transverse opening therethrough and an inwardly facing wall of the transverse opening is provided with a rack gear. The housing also supports a pinion gear, for rotation about its longitudinal axis, which extends through the transverse opening in the piston and has a plurality of teeth which engage with teeth of the rack gear. Rotation of the pinion effects sliding movement of the piston through the cylinder. The piston is biased towards one end of the housing by a spring and a hydraulic damper is also provided adjacent the spring. One end of the pinion gear is fixed to one end of a two-part arm. The two arm parts are pivotally connected to each other at corresponding ends with the free end of the second arm being pivotally connected to a frame supporting the door. The spring is positioned such that it effects closing of the door by effecting sliding movement of the piston through the cylinder which in turn rotates the pinion gear and the two-part arm. The hydraulic damper serves to provide smooth closing of the door. The force of the spring on the piston can be adjusted by compressing or decompressing the spring to increase or decrease the opening/closing force of the apparatus on the door.

[0003] Such rack and pinion door closers have been in existence since at least 1966 and the main components thereof have not been substantially modified. One example of an early door closer is disclosed in UK Patent No. 1,160,000.

[0004] Recently, criteria have been introduced to ensure that disabled persons can easily open a door which is fitted with such an apparatus as above described. One such criterion has been introduced as a result of the UK Disabled Discrimination Act 1995 and requires that the force required to open a door (the force being measured at an edge of the door remote from its hinged connection to the door frame), during the first 30° of angular movement should not exceed 30N and that the force required to open a door during the second 30° (i.e. 30° to 60°) of angular movement should not exceed 22.5N. However, these opening forces cannot be achieved by adjusting the compression of the spring, as this would compromise the closing force of the door, thus possibly breaching fire safety regulations.

[0005] It is documented that rack and pinion door closers are unlikely to be able to satisfy the requirements of the UK Disabled Discrimination Act 1995. Other types of door closers have therefore been developed, one of which is commonly known as a cam-action door closer. However, such door closers are more complicated in their component design than rack and pinion door closers and as such are more expensive to manufacture.

[0006] Therefore, according to a first aspect of the invention there is provided an apparatus for controlling angular movement of a door, the apparatus including:-

a housing;

a piston, having a longitudinal axis, slidable in a cylinder in the housing, the piston having a transverse opening therethrough, with an inwardly facing wall of the opening being provided with a rack gear having a plurality of teeth which are substantially transverse to the longitudinal axis of the piston; and

a pinion gear supported for rotation about its longitudinal axis by the housing and extending through the transverse opening in the piston, the pinion gear having a plurality of teeth which engage with the teeth of the rack gear, such that rotation of the pinion gear about its longitudinal axis effects sliding movement of the piston through the cylinder,

wherein a top land of each tooth of the pinion gear has two side portions each of which extends towards the longitudinal axis of the pinion gear at a homogenous gradient as it extends away from the other side portion.

[0007] By providing an apparatus in accordance with the present invention, the maximum force necessary to effect opening of the door compared to prior art apparatuses is reduced. Advantageously, the apparatus in accordance with the present invention can also be modified to ensure that the maximum force required to open the door does not exceed a predetermined value. For example, a maximum opening force may be stipulated by a national safety standard to ensure that disabled persons can easily open the door, whilst also taking into consideration the fact that the door must close behind that person quickly enough not to compromise fire safety standards. Of course, by reducing the force required to open the door, e.g. for a disabled person, one automatically reduces the closing force of the apparatus on the door, thus the door closing speed will be decreased.

[0008] The top land of each tooth of the pinion gear may have a substantially central portion, provided between the two side portions, which is substantially parallel to the longitudinal axis of the pinion gear. The central portion is beneficial in that it ensures positive meshing with the teeth of the rack gear. The length of the central portion can, of course, be reduced or increased to ensure that the maximum force required to open the door does not exceed a predetermined value.

[0009] According to a second aspect of the invention there is provided an apparatus for controlling angular movement of a door, the apparatus including:-

a housing;

a piston, having a longitudinal axis, slidable in a cylinder in the housing, the piston having a transverse opening therethrough, with an inwardly facing wall of the opening being provided with a rack gear having a plurality of teeth which are substantially transverse to the longitudinal axis of the piston; and

a pinion gear supported for rotation about its longitudinal axis by the housing and extending through the transverse opening in the piston, the pinion gear having a plurality of teeth which engage with the teeth of the rack gear, such that rotation of the pinion gear about its longitudinal axis effects sliding movement of the piston through the cylinder,

wherein a top land of each tooth of the pinion gear has a substantially central portion which is substantially parallel to the longitudinal axis of the pinion gear, and two side portions, each of which extends towards the longitudinal axis of the pinion gear as it extends away from the central portion.

[0010] Each side portion of the top land of the pinion gear in accordance with the second aspect of the invention may extend away from the substantially central portion at a homogenous gradient to the longitudinal axis of the pinion gear.

[0011] A bottom land between adjacent teeth of the pinion gear in accordance with the first and second aspects of the invention may be substantially parallel to the longitudinal axis of the pinion gear. This ensures that the teeth of the pinion gear mesh effectively with the teeth of the rack gear on the piston, and reduces the chance of the teeth slipping relative to each other if an excessively high external force is effected on the apparatus, e.g. by a person opening/closing the door too fast.

[0012] The width of the top land of each side portion of each tooth of the pinion gear may widen as it extends away from the substantially central portion of the pinion gear.

[0013] The angle of the homogenous gradient of each side portion to the longitudinal axis of the pinion gear may be in the range of 2° to 5°, preferably in the range of 3° to 5° and more preferably in the range of 3° to 4°. A steeper homogenous gradient to the longitudinal axis of the pinion gear ensures that the force required to effect opening of the door is reduced. Thus, beneficially, the homogenous gradient of each side portion of the top land of each tooth of the pinion gear can be calculated appropriate to the desired maximum opening force required.

[0014] The homogenous gradient of the side portions of each tooth of the pinion gear may be provided by machining the top land. This has the advantage of ensuring to a degree that the top land of all of the teeth of the pinion gear are substantially identical.

[0015] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, of which:-

Figure 1 is a side view of an apparatus in accordance with the present invention mounted on a door;

Figure 2 is a front view of one tooth of a pinion gear of the apparatus of figure 1;

Figure 3 is a plan view of the top land of the tooth shown in figure 2;

Figure 4 is a perspective view from one side an above of working components of the apparatus shown in figure 1; and

Figure 5 is perspective view from one side and above of a piston and a pinion gear of the apparatus shown in figure 4.

[0016] Referring to figure 1 there is shown an apparatus in accordance with the present invention, generally at 10. The apparatus 10 is connected to a door 11 which is hingedly connected (not shown) to a door frame 12. The internal workings of the apparatus 10, which will be discussed in greater detail below, are connected to the door frame 12 via a pair of arms 13, 14 which are pivotally connected to each other at corresponding ends by means indicated at 15. The free end of the arm 13 is connected at one end to the internal workings (pinion 30, discussed later) of the apparatus 10 and the free end of the arm 14 is connected to a bracket 16 which is connected to the door frame 12.
Referring to figure 4, this shows a perspective view from one side and above of working components of the apparatus 10. The apparatus 10 includes an aluminium housing 17 which is rectangular in cross-section, although it must be appreciated that the housing 17 could be made of any other suitable material and could have an alternative cross-section. The housing 17 has a cylinder 18 therethrough to receive a piston 20, which is shown in greater detail in figure 5. The piston 20 has a transverse opening 24 therethrough and an inwardly facing wall 26 of the opening 24 is provided with a rack gear 28 including a plurality of teeth 29 which are substantially transverse to a longitudinal axis 22 of the piston 20.

[0017] The apparatus 10 also includes a pinion gear 30 which is supported for rotation about its longitudinal axis 34 by supports 50 threadedly engaged with the housing 17 and including suitable bearings. The pinion gear 30 extends through the transverse opening 24 in the piston 20 and has a plurality of teeth 32 which engage with the teeth 29 of the rack gear 28. The axes 22 and 34 are substantially perpendicular to each other.

[0018] The piston 20 is biased towards one end A of the housing 17 by a spring (not shown), and hydraulic damper (also not shown) is also provided adjacent the spring.

[0019] Figures 2 and 3 show detailed front and top views, respectively, of a tooth 32 of the pinion gear 30. As can be seen from figure 2, the top land of the tooth 32 has a substantially central portion 52 which is substantially parallel to the axis 34 of the pinion gear 30, and two side portions 53, 54. Each side portion 53, 54 slopes towards the longitudinal axis 34 of the pinion gear 30 as it extends away from the central portion 52. The gradient of each side portion 53, 54 is homogenous, and in this particular example is at an angle of about 4° to the longitudinal axis 34 of the pinion gear 30. The tooth 32 also has end walls 55, 56 which extend toward each other as they extend away from the longitudinal axis 34 of the pinion gear 30.

[0020] Operation of the working components of the apparatus 10 is well known in the art. As the door 11 is opened, the pinion gear 30 is caused to rotate about its longitudinal axis 34 by the arm 13. Rotation of the pinion gear 30 causes the piston 20 to move away from the end A of the housing 17 which in turn compresses the spring (not shown) and the hydraulic damper (also not shown).

[0021] When the person opening the door 11 has passed through the door frame 12, the door 11 is then released and it is the apparatus 10 which effects closing of the door 11. This is achieved by the spring which, having been compressed by the piston 20, forces the piston 20 towards the end A of the housing 17, which in turn, rotates the pinion gear 30 in an opposite direction. The arm 13 is also rotated and, together with the arm 14, which is connected to the door frame 12, they move the door 11 towards the door frame 12.

[0022] The benefit of the apparatus 10 in accordance with the invention is that, whilst maintaining the operation of the apparatus, the force required to open the door 11 during the first 30° of angular movement is substantially reduced, and also the force required to open the door during the second 30° of angular movement is reduced. This is beneficial in that disabled persons wishing to pass through the door frame 12 can more easily open the door 11. Furthermore, the apparatus 10 can be calibrated to ensure that the force required to open the door 11 does not exceed a predetermined value.

[0023] Various modifications may be made to the apparatus without departing from the scope of the invention. For example, the top land of each tooth 32 of the pinion gear 30 may not include a central portion 52. Instead the side portions 53, 54 may abut each other. Furthermore, the gradient of each side portion 53, 54 need not be constant along its entire length. For example, there may be two or more stages of, e.g. increasing, gradient along its length as it extends away from the central portion 52, or the other side portion, as the case may be.

[0024] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. An apparatus (10) for controlling angular movement of a door (11), the apparatus(10) including:-

a housing (17);

a piston (20), having a longitudinal axis (22), slidable in a cylinder (18) in the housing (17), the piston (20) having a transverse opening (26) therethrough, with an inwardly facing wall (26) of the opening (24) being provided with a rack gear (28) having a plurality of teeth (29) which are substantially transverse to the longitudinal axis (22) of the piston (20); and

a pinion gear (30) supported for rotation about its longitudinal axis (34) by the housing (17) and extending through the transverse opening (24) in the piston (20), the pinion gear (30) having a plurality of teeth (32) which engage with the teeth (29) of the rack gear (28), such that rotation of the pinion gear (30) about its longitudinal axis (34) effects sliding movement of the piston (20) through the cylinder (18),

wherein a top land of each tooth (32) of the pinion gear (30) has two side portions (53,54) each of which extends towards the longitudinal axis (34) of the pinion gear (30) at a homogenous gradient as it extends away from the other side portion (53,54).

2. An apparatus (10) according to claim 1 wherein the top land of each tooth (32) of the pinion gear (30) has a substantially central portion (52), provided between the two side portions (53,54), which is substantially parallel to the longitudinal axis (34) of the pinion gear (30).

3. An apparatus (10) for controlling angular movement of a door (11), the apparatus (10) including:-

a housing (18);

a piston (20), having a longitudinal axis (22), slidable in a cylinder (18) in the housing (17), the piston (20) having a transverse opening (24) therethrough, with an inwardly facing wall (26) of the opening (24) being provided with a rack gear (28) having a plurality of teeth (29) which are substantially transverse to the longitudinal axis (22) of the piston (20); and

a pinion gear (30) supported for rotation about its longitudinal axis (34) by the housing (17) and extending through the transverse opening (24) in the piston (20), the pinion gear (30) having a plurality of teeth (32) which engage with the teeth (29) of the rack gear (28), such that rotation of the pinion gear (30) about its longitudinal axis (34) effects sliding movement of the piston (20) through the cylinder (17),

wherein a top land of each tooth (32) of the pinion gear (30) has a substantially central portion (52) which is substantially parallel to the longitudinal axis (34) of the pinion gear (30), and two side portions (53,54), each of which extends towards the longitudinal axis (34) of the pinion gear (30) as it extends away from the central portion (52).

4. An apparatus (10) according to claim 3 wherein each side portion (53,54) of the top land of the pinion gear (30) extends away from the substantially central portion (52) at a homogenous gradient to the longitudinal axis (34) of the pinion gear (30).

5. An apparatus (10) according to any preceding claim wherein a bottom land between adjacent teeth (32) of the pinion gear (30) is substantially parallel to the longitudinal axis (34) of the pinion gear (30).

6. An apparatus (10) according to any preceding claim wherein the width of the top land of each side portion (53,54) of each tooth (32) of the pinion gear (30) widens as it extends away from the substantiaiiy central portion (52) of the pinion gear (30).

7. An apparatus (10) according to any one of claims 1, 2 or 4, or claim 5 or 6 as appendant to claim 1, 2 or 4, wherein the angle of the homogenous gradient of each side portion (53,54) to the longitudinal axis (34) of the pinion gear (30) is in the range of 2° to 5°.

8. An apparatus (10) according to any one of claims 1, 2 or 4, or claim 5 or 6 as appendant to claim 1, 2 or 4, wherein the angle of the homogenous gradient of each side portion (53,54) to the longitudinal axis (34) of the pinion gear (30)is in the range of 3° to 5°.

9. An apparatus (10) according to any one of claims 1, 2 or 4, or claim 5 or 6 as appendant to claim 1, 2 or 4, wherein the homogenous gradient of each side portion (53,54) to the longitudinal axis (34) of the pinion gear (30) is in the range of 3° to 4°.

10. An apparatus (10) according to any preceding claim wherein the profile of each tooth (32) of the pinion gear (30) is achieved by machining the top land thereof.

Drawing