Door Closer Systems and Methods

TECHNICAL FIELD

This document relates to door closer devices.

BACKGROUND

Screen doors, storm doors, and other doors are installed onto doorways of buildings to provide air flow, daylight, weather protection, and security. Such doors may include a mechanism for closing the door. For example, some door closer devices can include a piston coupled with a cylindrical tube. The inner surface of the cylindrical tube generally includes a spring that biases the piston, which is attached to a reciprocating connecting rod extending out of the tube. The free end of the connecting rod can be attached to a bracket for mounting to the door frame, and the cylindrical tube can be coupled to a different bracket for mounting to the door. When the door is opened, the connecting rod is pulled from the cylindrical tube, causing the piston to travel within the inner surface of the cylindrical tube and thereby compress a spring coiled inside the cylindrical tube. When the door is released, energy stored within the spring pushes against the surface of the piston, causing it to slide within the cylindrical tube and thereby return the connecting rod is back within the cylindrical tube. Such action can cause the door to return to a closed position.

SUMMARY

Some embodiments of a door closer device can be configured to provide a reliable closing action while reducing the likelihood of internal failure even after repeated uses. In particular, some embodiments of a pneumatic door closer device can include a dual spring system in which the springs can avoid contact with one another and with the internal portion of the piston rod. In alternative embodiments, a hydraulic door closer device can include a cap seal assembly that reduces the likelihood of fluid leakage while also compensating for any wear of the dynamic seal interface between the piston rod and a surrounding seal.

In some embodiments, a door closer device for mounting to a door may include a housing that at least partially defines a piston chamber. The device may also include a piston arranged in the piston chamber. The device may further include a piston rod coupled to said piston. Also, the device may include first and second springs arranged in the housing to bias the piston toward a first end of the housing. The first and second springs may be generally coaxial with the piston rod and may be spaced apart from the piston rod. The first and second springs may be spaced apart from one another during movement of the piston rod relative to the housing.

Particular embodiments include a method of operating a door closer device. The method may include adjusting a piston rod relative to a housing of a door closer device from a first position to a second position so that the piston rod extends further from the housing. The door closer device may include first and second springs arranged in the housing to selectively bias the piston rod toward the first position. The method may also include compressing the first spring in response to the adjustment of the piston rod while not compression the second spring. The method may include further extending the piston rod from the housing of the door closer device so that the piston rod adjusts from the second position to a third position. The method may further include compressing both the first spring and the second spring in response to the adjustment of the piston rod from the second position to the third position. The first and second springs may be spaced apart from the piston rod and avoid contact with one another during movement of the piston rod relative to the housing.

In other embodiments, a door closer system may include a door hingedly mounted in a door frame and a door closer device. The door closer device can include a piston rod extending from an elongate housing. The piston rod may be mounted to the door frame by a first mounting bracket, and the housing may be mounted to the door by a second mounting bracket. The door closer device may also include a first spring and a second spring arranged in the housing to bias the door to a closed position. The first and second springs may generally coaxial with the piston rod and may be spaced apart from the piston rod. Also, the first and second springs may be spaced apart from one another during movement of the piston rod relative to the housing.

Certain embodiments may include a door closer device for mounting to a door. The device may include a housing having an elongate body that at least partially defines a piston chamber. The device may also include a piston movably mounted in the piston chamber. The device may further include a piston rod coupled to said piston and movable relative to the housing. Also, the device may include a first spring arranged in the housing to bias the piston toward a first end of the housing. The device may include a cap seal assembly proximate to a second end of the housing to hinder leakage of fluid from the housing. The cap seal assembly can comprise a washer seal that defines an annular seal face to slidingly abut the piston rod. The washer seal may include a radial compression spring that urges the annular seal face radially inward toward the piston rod.

In some embodiments, a method of operating a door closer device includes adjusting a piston rod relative to a housing of a door closer device from a first position to a second position so that the piston rod extends further from the housing. The door closer device may have a compression spring arranged in the housing to bias the piston rod toward the first position. The method may also include dynamically sealing an interface between a cap seal assembly in the door closer device and the piston rod in response to the adjustment of the piston rod. The dynamic seal can hinder leakage of fluid from the housing of the door closer device. Also, the cap seal assembly may include no more than one metal-on-metal interface with the piston rod. The method may further include returning the piston rod from the second position to the first position in response to the bias from the compression spring.

In other embodiments, a door closer system may include a door hingedly mounted in a door frame, and a door closer device. The door closer device may include a piston rod extending from an end of an elongate housing. The piston rod may be mounted to the door frame by a first mounting bracket, and the housing may be mounted to the door by a second mounting bracket. The door closer device may also include a cap seal assembly proximate to the end of the housing to hinder leakage of fluid from the housing. The cap seal assembly may comprise a washer seal that defines an annular seal face to slidingly abut the piston rod. The washer seal may include a radial compression spring that urges the annular seal face radially inward toward the piston rod.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a top view of a door closer device mounted to a door frame and a door, in accordance with some embodiments.

FIG. 2 is a cross-sectional view of the door closer device of FIG. 1. FIG. 3 is another cross-sectional view of the door closer device of FIG. 1. FIG. 4 is another cross-sectional view of the door closer device of FIG. I .

FIG. 5 is a cross-sectional view of an alternative door closer device for mounting to a door frame and a door, in accordance with particular embodiments.

FIG. 6 is a magnified cross-sectional view of a portion of the door closer device of FIG. 5. Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1 , a door closer device 100 can be mounted to a door 40 and an associated door frame 50 so as to bias the door 40 toward a closed position within the frame 50. In such a system 10, the door 40 can be movably mounted to the door frame 50 via one or more hinges 45 such that a latch device 48 can be actuated and swung away from the door frame 50. The latch device 48 may include door handle hardware that permits a user to adjust the door between a locked condition and an unlocked condition. For example, the latch device 48 can retain the door 40 in the closed position when the latch device 48 engages a mating structure 58 on the door frame 50. The door closer device 100 includes a housing 1 10 and a piston rod 125 that at least partially extends from the housing 1 10. In this embodiment, the housing 1 10 is pivotably mounted to the door 40 via a mounting bracket 1 14. Also, an exposed end of the piston rod 125 may be pivotably mounted to the door frame via another mounting bracket 1 15. As such, when the door 40 is adjusted from a closed position to an opened

position, the piston rod 125 extends further out of the housing 110. As described in more detail below, the piston rod 125 may be coupled to a piston assembly (not shown in FIG. 1) that is reciprocally disposed within the housing 110. The piston assembly can be biased by one or more springs arranged in the housing 110 so as to compel the piston rod 125 further into the housing 110. As such, the door closer device 100 can operate to bias the door 40 toward a closed position within the frame 50.

Referring to FIG. 2, in some embodiments, the door closer device 100 can include a plurality of springs arranged in the housing 110 to provide a reliable closing action while generally avoiding interference with one another. For example, the door closer device can include a first spring 130 and a second spring 140 that are arranged generally coaxially with the portion of the piston rod 125 inside the housing 110. The first spring 130 may be a coil spring having a larger diameter than the second spring 140. As such, the first spring 130 can be axially aligned with the second spring 140 and can extend over the second spring 140 between the piston assembly 120 and a cap member 135. The second spring 140 can be axially aligned with the piston rod 125 and can extend between opposing spring seats 142 and 144 that retain the second spring 140 in a position around the piston rod 125 without directly contacting the piston rod 125. Accordingly, the first spring 130 and the second spring 140 can be coaxially arranged with the piston rod 125 while avoiding direct contact with the piston rod 125 and avoiding interference between the springs 130 and 140. In such circumstances, the door closer device 100 can be operated in a reliable manner that provides a general reduction is spring movement noise and that reduces the likelihood of failure of internal components.

In more detail, the housing 110 can optionally include a cylindrical body having an inner surface 112 that sliding engages the piston assembly 120. In this embodiment, the piston assembly 120 includes a piston head 122 that receives an o-ring seal 123 to seal in the interface between the inner surface 1 12 and the piston assembly 120. The piston head 122 can be secured to the piston rod 125 using a rivet 126 or other fastening instrument such that the piston rod 125 extends from the piston head 122 along a central axis of the housing 1 10. In such circumstances, the piston head 122 (and the o-ring seal 123) can be guided along the inner surface 112 of the housing 1 10 as the piston rod 125 moved relative to the housing 110.

Still referring to FIG. 2, the housing 110 may include an end plug 117 arranged at a first end 1 11 of the housing 110 opposite of the piston rod 125. The end plug 1 17 can include one or more mounting holes that are configured to mate with the mounting bracket 114 (FlG. 1) that attached to the door 40. As such, the housing 1 10 can be mounted to the door 40 when the end plug 1 18 engages the mounting bracket 114. The end plug 117 may receive a closure adjustment screw 118 that can be used to control the door speed during the closing action. For example, in this embodiment, the door closer device 100 may be configured as a pneumatic instrument that permits the passage of air through small ports in the end plug 117 as the piston assembly 120 is urged away from the end plug 117 toward a second end 1 19 (e.g., by the force of opening the door 40). When the piston assembly 120 is returned toward the first end 111 (e.g., toward the end plug 117 in this embodiment), the air can escape through the one or more ports. However, the air escape may be constricted by the closure adjustment screw 119 so that the movement of the piston assembly is dampened or otherwise slowed as it returns toward the first end 111 (e.g., toward the end plug 117 in this embodiment).

As previously described, the door closer device 100 can include a cap member 135 that is used to engage one end of the first spring 130 while the other end is engaged by the piston head 122. The cap member 135 can be arranged proximate the second end 119 of the housing 110. For example, in this embodiment, the cap member 135 abuts against the second end 119 of the housing 110 due to the compression of the first spring 135 inside the housing 110 between the piston head 122 and the cap member 135. The cap member 135 and the second end 119 of the housing 110 can include an opening through which the piston rod 125 extends. In some embodiments, the cap member 135 may comprise a resilient polymer material that permits a dynamic interface with the piston rod 125 (through the center bore) while providing protection against migration of external contaminants (e.g., dirt, rain, or the like). As such, that cap member 135 can maintain the piston rod 125 generally in axial alignment with the central axis of the housing 110 while the piston rod 125 is moved relative to the housing 110. Likewise, the cap member 135 can engage the first spring 130 so as to maintain the first spring 130 generally in axial alignment with the central axis of the housing 110 while the first spring 130 is compressed and relaxed inside the housing 110.

Still referring to FIG. 2, the second spring 140 may also be arranged inside the housing U O in a position that is generally in axial alignment with the central axis of the housing 1 10. As previously described, each end of the second spring 140 can mate with a spring seat 142 or 144 so that the second spring remains spaced apart from the piston rod 125 and coaxial with the piston rod 125. The spring seats 142 and 144 may comprise a resilient polymer material that frictionally engages the piston rod 125. As such, the second spring 140 does can remain generally stationary inside the housing until the second spring is compressed (refer to FIG. 4). For example, the spring seats 142 and 144 can hold the second spring 140 in place during compression and relaxation of only the first spring 130, thereby reducing or eliminating noises that would ordinarily occur if the second spring scraped along the piston rod 125 during movement of the piston rod 125 and the first spring 130. The frictional engagement between the piston rod 125 and the spring seats 142 and 144 permits relative sliding if a compression force is applied to the second spring 140. However, during compression of the second spring 140, the spring seats 142 and 144 maintain the second spring 140 in a coaxial position with the first spring 130 so as to avoid interference or other contact between he first and second springs 130 and 140. Such a configuration can reduce or eliminate noises that would ordinarily occur if the second spring pushes against the first spring during movement of the springs 130 and 140. Moreover, because the two springs 130 and 140 can operate within the housing 110 while avoiding direct contact with the piston rod 125 and while avoiding interference between the springs 130 and 140, the door closer device can reduce the likelihood of failure of internal components (e.g., damage from scraping along the piston rod 125, damage from scraping or bending of a spring when the springs interfere with one another, or the like). Referring now to FIGS. 3-4, the door closer device 100 may include a dual spring arrangement that provides multiple levels of biasing force to urge the door 40 toward the closed position (or to resist movement of the door 40 to an opened position). As previously described, this dual spring arrangement can be configured to urge the door 40 toward the closed position while reducing the device noise associated with the internal spring movements and while reducing the likelihood of failure of internal components.

As shown in FIG. 3, the piston rod 125 may be adjusted to an intermediate position (e.g., displace by a first distance 127) when a first force 137 is applied to the piston rod 125. For example, the first force 137 may be applied to the piston rod 125 when the door 40 is shifted to a partially opened position (as shown in FIG. 1) during normal use of the door 40. When the piston assembly 120 is displace by the first distance 127, the first spring 130 is compressed between the piston head 122 and the cap member 135. Such compression of the first spring 130 creates a biasing force that urges the piston rod 125 to return toward the first end 111 of the housing 1 10, thereby biasing the door 40 (FIG. 1) to return toward the closed position. Even during this compression, the first spring 130 can be maintained in a generally coaxial position with the piston rod 125.

Also, the second spring 140 is maintained in a generally coaxial position with the piston rod 125 due to the engagement between the spring seats 142 and 144. In this embodiment, when the piston assembly 120 is displaced by the first distance 127, the second spring 140 is not necessarily compressed because the second spring 140 has a shorter length than the first spring 130. As such, the first spring 130 can be compressed between the piston head 122 and the cap member 135 (without the compression of the second spring) to provide a first level of biasing force from the door closer device 100.

As shown in FIG. 4, continued movement of the door 40 may cause the piston rod 125 to further extend to a second position (e.g., displace by a second distance 128). This continued movement of the door can cause a second force 148 to be applied to the piston rod 125, thereby causing the displacement to the second distance 128. For example, the second force 148 may be applied when the door 40 is further shifted beyond the partially opened position (as shown in FIG. 1) toward a more fully opened position in response to a user's act, a wind gust, or other substantial force). When the piston assembly 120 is displace by the second distance 128, both the first spring 130 and the second spring 140 are compressed between the piston head 122 and the cap member 135. Such compression of the first and second springs 130 and 140 creates a greater biasing force that urges the piston rod 125 to return toward the first end 111 of the housing 110, thereby biasing the door 40 (FIG. 1) to return toward the closed position. The second spring 140 may provide a different spring constant from the first spring 130 such that the additional biasing force from compression of the second spring 140 is perceivable by a user of the

door. For example, the second spring 140 may include a greater spring constant value than the first spring 130 so that the compression of the second spring substantially adds to the biasing force. Such a configuration may be useful, for example, when the door 40 is rapidly urged toward a more fully opened position in response to a strong wind gust or another substantial force. In such circumstances, the compression of the second spring 140 can resist or slow the otherwise rapid opening motion that could harm the door 40, the frame 50, a nearby person, or the like.

Still referring to FIG. 4, even during this compression of the first and second springs 130 and 140, both springs 130 and 140 can be maintained in a generally coaxial position with the piston rod 125. As previously described, the first spring is maintained in axial alignment with the piston rod 125 due to the engagement with the piston head 122 and the cap member 135. Also as previously described, the second spring 140 is maintained in axial alignment with the piston rod 125 and with the first spring 130 due to the engagement between the spring seats 142 and 144. The spring seats 142 and 144 can frictionally slide along the piston rod 125 during compression and. relaxation of the second spring 140. Thus, when the second spring 140 undergoes compression, the spring seat 142 can abut against the cap member 135 and the opposing spring seat 144 can abut against the piston head 122. As such, both the first spring 130 and the second spring 140 can be compressed between the piston head 122 and the cap member 135 to provide a second level of biasing force from the door closer device 100.

Furthermore, as previously described, the door closer device 100 may be configured so that the first spring 130 and the second spring 140 are coaxial with the piston rod 125 while avoiding direct contact with the piston rod 125 and avoiding interference between the springs 130 and 140. In such circumstances, the door closer device 100 can be operated in a reliable manner that provides a general reduction is spring movement noise (e.g., reducing or eliminating noises that would ordinarily occur if the second spring scraped along the piston rod 125, reducing or eliminate noises that would ordinarily occur if the second spring 140 pushed against the first spring 130 during movement of the springs 130 and 140, or the like). Moreover, because the two springs 130 and 140 can avoid interference from other components inside the housing 1 10, the door closer device 100 can reduce the likelihood of failure of internal components (e.g.,

damage from a spring scraping along the piston rod 125, damage from scraping or bending of a spring when the springs 130 and 140 interfere with one another, or the like). Turning now to FIGS. 5-6, some alternative embodiments of a door closer device 200 can also be implemented into the system 10 (FIG. 1) having a door 40 hingedly mounted to a door frame 50. For example, the door closer device 200 depicted in FIG. 5 may be configured as a hydraulic instrument that can be mounted to the door 40 as an alternative to the door closer device 100 having the pneumatic instrument (described in connection with FIGS. 2-4). In such embodiments, the door closer device 200 can include a number of features that reduce the likelihood of fluid leakage or damage to the internal components.

As shown in FlG. 5, the door closer device 200 includes a housing 210 and a piston rod 225 that at least partially extends from the housing 210. Similar to previously described embodiments, the housing 210 comprises a cylindrical body that can be pivotably mounted to the door 40 via a mounting bracket (e.g., bracket 114 in FIG. 1). Also, the exposed end of the piston rod 225 can be pivotably mounted to the door frame via another mounting bracket (e.g., bracket 115 in FIG. 1). As such, when the door 40 is adjusted from a closed position to an opened position, the piston rod 225 extends further out of the housing 210. As described in more detail below, the door closer device 200 can operate to bias the piston rod 225 to return into the housing 210, and thereby urge the door 40 toward a closed position.

The housing 210 can define an inner surface 212 that sliding engages a piston assembly 220. In this embodiment, the piston assembly 220 includes a piston head 222 that receives a washer seal 223 to at least partially seal in the interface between the inner surface 212 and the piston assembly 220. The piston head 222 can be secured to the piston rod 225 so that the piston rod 225 extends from the piston head 222 along a central axis of the housing 210. In such circumstances, the piston head 222 (and the washer seal 223) can be guided along the inner surface 212 of the housing 110 as the piston rod 225 moved relative to the housing 210.

Still referring to FIG. 5, the housing 210 may include an end plug 217 arranged at a first end 211 of the housing 210 opposite of the piston rod 225. Similar to previously described embodiments, the end plug 217 can include one or more mounting holes (not

shown in FIG. 5) that mate with a mounting bracket. As such, the housing 210 can be mounted to the door 40 when the end plug 217 engages the mounting bracket. When the door 40 is adjusted from a closed position to an opened position, the piston rod 225 extends further out of the housing 210, thereby drawing the piston head 222 to move toward a second end 219 of the housing. In such circumstances, hydraulic fluid disposed in the housing 210 may pass by the piston head 222 (e.g., though one or more ports formed in the piston head 222, or the like) toward a cavity defined by a first end seal 226. When the piston head 222 moves in this manner, a spring 230 is compressed and thus biases the piston head 222 to return toward the first end 211 of the housing. During this return motion, the hydraulic fluid arranged in the cavity adjacent to the first end seal 226 can pass by the piston head 222 into a second cavity opposite of the first end seal 226 (e.g., the cavity containing the spring 230. The flow of the hydraulic fluid passing by the piston head 222 and toward the second cavity may be partially restricted by the piston head 222 so that the movement of the piston assembly 220 is dampened or otherwise slowed as it returns toward the first end 211.

In this embodiment, the first end seal 226 remains generally stationary in the housing 210. As such, the first end seal 226 provides a static seal interface along one or more o-ring seals 227. For example, the first end seal 226 can comprise a metallic material having one or more grooves to receive the one or more o-ring seals 227. In another example, the first end seal 226 can comprise a polymer material that is molded to define one or more grooves to receive the one or more o-ring seals 227. Alternative, the first end seal 226 can be integrally formed with the end plug 217 and thereafter assembled into the housing with one or more o-ring seals 227. Such configurations permit the first end seal 226 to retain the hydraulic fluid in the housing 210 and hinder fluid leakage toward the end plug 217.

Referring to FIGS. 5-6, the door closer device 200 can include a cap seal assembly 240 that is arranged proximate the second end 219 of the housing 210 (opposite the first end seal 226. The cap seal assembly 240 defines a central bore through which the piston rod 225 passes. Because the piston rod 225 reciprocates relative to the cap seal assembly 240 (during opening and closing of the door 40 (FIG. I)), the interface between the cap seal assembly 240 and the piston rod 225 includes a dynamic seal configuration.

The door closer device 200 can be equipped with the cap seal assembly 240 that is adapted to reduce the likelihood of fluid leakage even after a great number of actuations of the piston rod 225, thereby providing the door closer device 200 with a generally greater operational life. As shown in FIG. 6, the cap seal assembly 240 includes a cap member 242 that receives at least one o-ring seal 243 along an outer periphery. The cap member 242 may comprise a metallic material that is formed with a groove to receive the o-ring seal 243. For example, the cap member 242 may comprise a zinc alloy material that provides sufficient strength and that can be formed in a molding procedure for close manufacturing tolerances. As such, the o-ring seal 243 can engage the inner surface 212 of the housing 210 to form a peripheral seal while also operating to maintain the cap member 242 is a centered position (e.g., so that the cap member 242 and the piston rod 225 are maintained in a coaxial relation ship). This construction can provide the cap seal assembly 240 with significant rigidity (due to the metal cap member 242) and a close fit between the cap member 242 and the piston rod 225. Alternatively, the cap member 242 may comprise a rigid polymer material that is molded to define an inner bore that receives the piston rod 225.

The cap seal assembly 240 may also include a washer seal 245 and a spring seat 248. In some embodiments, the washer seal 245 and the spring seat 248 do not provide a metal-on-metal interface with the piston rod 225 that could scrape or corrode the piston rod during the reciprocating movements. As described in more detail below, the washer seal 245 and the spring seat 248 may comprise polymer materials that interface with the piston rod 225 so as to reduce the likelihood of damage or corrosion to the piston rod 225 during operation. Thus, in some embodiments, the cap seal assembly 240 may include no more than one metal component (e.g., the cap member 242) that interfaces with the piston rod, which is different from other door closer devices that include a cap seal with multiple metal components that slide along the piston rod during operation.

Still referring to FIG. 6, the washer seal 245 can be arranged to tightly seal against the piston rod 225 in a manner that reduces the likelihood of damage to the piston rod 225. Furthermore, the washer seal 245 can engage the piston rod 225 in a manner that reduces the likelihood of fluid leakage even if the dynamic seal surface of the washer seal

245 is worn due to reciprocation of the piston rod 225. In particular, the washer seal 245 may comprise a resilient elastomeric material (e.g., rubber or the like) that includes a radially extending portion that transitions to an annular seal face 246. The annular seal face 246 defines a seal surface that abuts against the piston rod 225 to hinder leakage of the hydraulic fluid. Thus, the washer seal 245 provides a nonmetal-to-metal interface with the piston rod 225, which can reduce the likelihood of scuffing the piston rod 225. In this embodiment, the washer seal 245 comprises a ring-shaped seal spring 247 that wraps around an outer periphery of the annular seal face 246 to squeeze the annular seal face 246 radially inward toward the piston rod 225. In such circumstances, the seal spring 247 maintains a tight seal around the piston rod 225 even if the dynamic seal surface of the washer seal 245 is worn due to reciprocation of the piston rod 225. If, for example, the annular seal face 246 becomes worn during the operational life of the door closer device 200, the radial compression force from the seal spring 247 compensates for this worn surface so as to maintain the seal interface during reciprocation of the piston rod 225.

The washer seal 245 can include one or more structures that facilitate assembly with the cap member 242 or the spring seat 248. In this embodiment, the washer seal includes a first annular ridge 241 that mates with a groove defined in the cap member 242. Such a configuration serves to maintain alignment between the washer seal 245 and the cap member 242 during assembly and during operation of the door closer device 200. In addition, the washer seal 245 may include a second annular ridge 249 arranged on an opposite face so as to engage a mating groove defined in the spring seat 248. Again, the connection between the washer seal 245 and the spring seat 248 can maintain alignment between the washer seal 245 and the spring seat 248 during assembly and during operation of the door closer device 200. Also, the washer seal 245 may include an outer peripheral seal surface that abuts against the inner surface 212 of the housing 210. Such a peripheral seal surface can be used to hinder leakage of the hydraulic fluid along the wall of the housing 210.

Still referring to FIG. 6, the cap seal assembly 240 includes the spring seat 248 so as to engage one end of the bias spring 230 that biases the piston assembly 220. For example, in this embodiment, the spring seat 248 used to engage one end of the bias

spring 230 while the other end is engaged by the piston head 222. The spring seat 248 can include an opening through which the piston rod 225 extends. The spring seat 248 may comprise a polymer material that is molded to define an inner bore that has close tolerances with the piston rod 225. As such, the spring seat 248 can be arranged generally coaxial with the piston rod 225, and can provide a nonmetal-to-metal interface with the piston rod 225 to thereby reduce the likelihood of scuffing the piston rod 225. The spring seat 248 can also engage the bias spring 230 so as to maintain the bias spring 130 generally in coaxial alignment with piston rod while the bias spring 130 is compressed and relaxed inside the housing 110. The bias spring 230 is compressed between the piston head 222 and the spring seat 248 when the piston assembly 220 is displaced inside the housing 210. For example, during operation the piston assembly 220 may be displaced relative to the housing 210 when a force is applied to the piston rod 225 (e.g., when the door 40 is shifted to an opened position as shown in FIG. 1). Such compression of the bias spring 230 creates a biasing force that urges the piston rod 225 to return toward the first end 211 of the housing 210, thereby biasing the door 40 (FIG. 1) to return toward the closed position. During this return motion, the hydraulic fluid arranged in the cavity adjacent to the first end seal 226 can pass by the piston head 222 (e.g., though one or more ports formed in the piston head 222, or the like) into the second cavity opposite of the first end seal 226 (e.g., the cavity containing the spring 230). The flow of the hydraulic fluid passing by the piston head 222 and toward the second cavity may be partially restricted by the piston head 222 so that the movement of the piston assembly 220 is dampened or otherwise slowed as it returns toward the first end 211. The bias spring 230 of the door closer device 200 may continue to urge the piston assembly 222 inside the housing 210 until the door 40 returns to the closed position relative to the door frame.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the scope of the invention. Accordingly, other embodiments are within the scope of the following claims.