A service tool and method of use is provided for the extraction and installation of bushings into vehicular suspension.
The suspension for heavy vehicles, including trucks and trailers, is typically supported with leaf springs and beam suspensions. Beam suspension and leaf springs are positioned between an axle, or axle assembly, and the load carrying frame. Beams and leaf springs are normally terminated at each of two ends with a circular eyelet. A bushing passes though the eyelet and connects at bushing pin ends to a hanger or other structure secured to the vehicle frame. The bushing includes an annular elastomeric element (rubber or polyurethane) about the pin to provide some vibration isolation and permit some limited rotation at the eyelet.
As an example, leaf springs are manufactured of spring steel and, over time, rust can form between the eyelet and the bushing, causing difficulty during eventual replacement. In highway trailer axle assemblies, which operate in severe conditions, bushings can require replacement at frequent intervals.
Applicant's experience has been that bushing replacement, such as that for suspensions including a variety of Henrickson suspension (Hendrickson Truck Systems Group, Woodridge, Ill., USA), can require removal of the suspension and use of a hydraulic press, typically found in a service shop environment, to force the bushing from the eyelet.
For example, refurbishing of bushings for a tri-axle trailer entails: removal of the six leaf springs, press removal of the bushings, installation of a new bushings and reinstallation of the six leaf springs on the trailer. This operation can take as much as 6 to 8 hours and require access to a shop press.
In embodiments described herein, a service tool is provided for facilitating bushing replacement without removal of suspension from a vehicle, including trucks and trailers. The tool is lightweight and usable by one person for reducing the time needed for bushing replacement to about one-half of that currently required. For example, re-bushing a tri-axle trailer can now take as little as 3 hours. The tool can be used in the field or in a shop environment.
In one aspect, a service tool for extracting and installing a bushing in an eyelet of a vehicular suspension comprises a frame having an actuator end and a tool end, the actuator end and tool end aligned along a longitudinal tool axis. The tool end forms a housing port, open laterally to a side of the frame, and is aligned along the tool axis between an anchor plate and the actuator end. The anchor plate is connected to the actuator end and has an extraction port therethrough along the tool axis. The housing port is sized to accept the suspension from the side of the frame with the housing adjacent the anchor plate. A bushing is aligned along the tool axis, and the actuator is operable between the actuator end and the bushing. When actuated, the actuator, supported at the actuator end, urges the suspension to bear against the anchor plate for support. For installation, the bushing is urged into the supported suspension. For extraction, the bushing is urged out of the supported suspension and at least partially through the through port.
The actuator can be a portable hydraulic jack, the actuator end having an open side for removably receiving the jack therein.
In another aspect, a method for insitu extraction and installation of bushings from and into an eyelet of a vehicular suspension using a service tool is provided comprising disconnecting the suspension bushing from the vehicular frame, the bushing supported in a suspension eyelet and orienting the service tool's tool end over the eyelet and bushing. Then one commences jacking against an actuator end of the service tool to drive against the bushing. The eyelet is supported at the tool end and, for installation, one drives the bushing into the eyelet suspension, and, for extraction, one drives the bushing out of the eyelet.
Replacement of a vehicular suspension bushing without the need to remove the suspension from the vehicle saves significant time and is convenient. A service tool is described herein in the context of a leaf spring suspension, however the tool is equally applicable to other eyelet and bushing arrangements such as that in beam-type and other forms of suspension S.
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The first tool end 24 has an open, C-shape housing port 28 for straddling the suspension S and bushing 10. The bushing 10 has a bushing axis BA which is concentric with the eyelet 12. The bushing axis BA is alignable with the tool axis A.
The second actuator end 26 provides a support from which to exert a bushing-extraction force. The service tool 20 is used in combination with an actuator 30 such as a jack for imparting the bushing-extraction force. The jack may be incorporated into the actuator end 26 or be removably positioned therein. A suitable jack is a portable hydraulic ram or power pack. The tool end 24 has an anchor plate 40 spaced apart from an interface plate 42 forming first and second straddle plates for forming the housing port 28 therebetween. The anchor plate 40 and interface plate 42 are connected by a wall or spacer 41 extending between the plates 40,42. The spacer 41 is circumferentially discontinuous for forming the housing port 28, yet structurally connects the anchor plate 40 and interface plate 42 together to transfer sufficient jacking forces to extract or install a bushing 10 from or into the suspension S.
The housing port 28 is open laterally to a side of the frame 22, the housing port sized to accept the suspension from a side of the frame 22 with the suspension arranged generally adjacent the anchor plate 40 and the bushing 10 aligned along the tool axis A.
As shown in
The frame's actuator end 26 comprises a tubular structure fit with a base plate 44 connected to, and spaced from, the tool end 24 for receiving the actuator 30 in bore 27 therebetween. The actuator end 26 is formed with an open side 46 for access to the bore 27 and receiving the jack 30 therein. The interface plate 42, connected to the actuator end 26 opposing the base end 44, is formed with a passage 48 therethrough sized to freely pass the bushing 10 and access to the suspension S. The anchor plate 40 is similarly formed with an extraction port 50 sized to freely pass the bushing 10 during extraction.
One form of actuator 30 is a linear actuator such as a hydraulic ram having a ram base or supported end 36, and a ram working end 32 movable relative to the supported end 36
When imparting force to the bushing, the actuator 30 is supported at an actuator's supported end 36 against the frame's base plate 44 for enabling a driving movement of the working end 32 away from the baseplate 44. Initially, the working end 32 urges the bushing 10, eyelet 12 and suspension S to bear against the anchor plate 40, and once the suspension is braced, the bushing can be driven relative thereto. The actuator 30 has an actuator diameter D. The hydraulic ram form of actuator comprises a hydraulic cylinder having laterally extending hydraulic line 38. The open side 46 is available for receiving and accommodating the line 38.
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The actuator 30 provides the jacking force necessary to move the bushing 10 out of or into supported suspension S. The actuator can be a pushing device such as a portable power hydraulic unit (such as that represented in
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Extraction
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One end of the bushing, such as the first end 61, may have a washer portion 66 extending radially beyond the pin and over the rubber portion 64. The adapter 34 is generally cylindrical and has a recess 70 at a first bushing end 72 and a pushing surface 74 at the opposing working end 76. The bushing end 72 has an annular shoulder 80 about the recess 70. The adapter recess 70 is aligned to receive the pin's second end 62 and the annular shoulder 80 engages the rubber portion 64. During extraction, the adapter's annular shoulder 80 pushes on the rubber to avoid merely extracting the pin 60 from the rubber and instead ensures both pin 60 and rubber 64 are extracted from the eyelet 12.
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Installation
Typically a new bushing 10 is installed from the same side of the suspension S that the old bushing was extracted, particularly where the bushing incorporates the washer 66 at the pin's first end 61. Accordingly, and having reference to
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The pins 60 of the new bushing 10 can be reconnected and reinstalled to the vehicle's frame hangers and the service personnel can move to the next bushing.
Example dimensions for a service tool 20 suitable for servicing Hendrickson suspensions include a frame having an actuator end connecting spacer 52 formed of 16 inch length of four inch Sch. 40 pipe. The diameter and structural spacer portion 41 of the tool end 24 is formed by a six inch length of eight inch Sch. 80 pipe, the circumference of the pipe being discontinuous and forming an arc, being about 270 degree or sufficient to form about a seven inch opening to admit a leaf spring eyelet 12. In this embodiment, the pipe axes are parallel, yet offset by about ¾ inches. The tool end 24 pipe arc spaces the straddle plates of the anchor and interface plates 40, 42. The anchor plate can be an eight inch diameter, ¾ inch plate and the interface plate can be an eight inch diameter, ½ inch plate situate between the tool end 24 and the actuator end 26. The actuator end 26 is fit with a ¾ inch base plate 44, the base plate being spaced from the interface plate by the connecting spacer 52 formed of the four inch pipe. The interface plate 42 is fit with a 3⅜ inch diameter passage 48, aligned with the tool axis A, suitable to pass a bushing 10 therethrough. The anchor plate 40 is fit with the extraction port 50, again sized to pass a bushing 10, the extraction port 50 being aligned with the tool axis A. The open side 26 of the actuator end pipe is sized to accept a hydraulic ram, for example, the first slot 46a extending longitudinally away from the interface plate 42 having a slot width Wa of about 3¼ inches and a length of 6½ inches. The remaining open side or second slot 46b extends longitudinally towards the base plate 44 and can be sized smaller than the cylinder diameter of the hydraulic ram actuator 30, but sufficient to pass the hydraulic hose 38 without interference. A slot width Wb of 2½ inches is suitable. The four inch pipe 52 to interface plate 42 connection is strengthened with a pair of ¼ thick gusset plates 54,54 straddling the open side 46 of the jack housing. The entire tool 20 can be formed of steel for ease of manufacture using welding techniques although other suitably strong materials of construction and machined components and assembly are contemplated.
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Number | Date | Country | |
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20130074306 A1 | Mar 2013 | US |
Number | Date | Country | |
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61538695 | Sep 2011 | US |