WO2002000386A1

WO2002000386A1 - Connecting rod fracturing fixture

Info

Publication number: WO2002000386A1
Application number: PCT/US2001/041078
Authority: WO
Inventors: Daniel D. Lamire; Joel W. Jones
Original assignee: Federal-Mogul Corporation
Priority date: 2000-06-23
Filing date: 2001-06-21
Publication date: 2002-01-03
Also published as: AU2001273612A1

Abstract

The rod cap fracturing machine (10) is for cracking a rod cap (68) along a rod cap cracking plane (P) that is intersected by connecting rod center line (110) at an acute angle. The machine includes a first mandrel portion (58) fixed to a frame (12) and a second mandrel portion (60) on a carriage (40). A rod cap clamp assembly (74) on the carriage clamps the rod cap to the second mandrel portion. First and second wrist pin clamps (116, 118) clamp the wrist pin end (106) of the rod body along a line (124) perpendicular to the rod center line and prevent pivotal movement of the rod body relative to the crankshaft bore axis (114). A crankshaft end clamp (128) clamps the rod body to the first mandrel half and prevents bending of the long arm (134) of the rod.

Description

CONNECTING ROD FRACTURING FIXTURE

BACKGROUND OF THE INVENTION 1.Technical Field

This invention is in a connecting rod fracturing machine for separating rod caps from connecting rod bodies of non symmetrical connecting rods. 2. elated Prior Art

Connecting rods for internal combustion engines have a wrist pin or gudgeon that pivotally connects a piston to a connecting rod. A crankshaft end of a connecting rod is rotably journaled on a crankshaft throw. A wrist pin is inserted through a bore through the piston and through a bore passage through the wrist pin end of the connecting rod prior to inserting the piston into a cylinder block. The crankshaft of multi cylinder internal combustion engines have webs on both ends of each throw. To connect a connecting rod to one of the throws, the connecting rod must have a rod cap that is clamped to the rod body by mechanical fasteners.

Connecting rods are generally formed by forging or by casting. The rod cap is formed initially as an integral part of the rod body. The rod cap is then separated from the rod body. Following separation, the rod cap is clamped to the rod body and the crankshaft bore is machined to receive rod bearings. Rod caps have been separated from rod bodies by sawing, grinding or other machining procedures. Caps have also been separated by fracturing. Fracturing, which is also referred to as cracking, has been used to separate rod caps from rod bodies of symmetrical connecting rods. Symmetrical connecting rods have a center line that passes through the axis of the wrist pin bore and the axis of the crankshaft journal bore and a rod cap separation plane that is perpendicular to the center line.

The primary forces applied to a symmetrical connecting rod by a rod cap cracking machine are parallel to the connecting rod center line. A two piece mandrel assembly is received in the crankshaft journal bore. A force is applied to the wrist pin end of the connecting rod to clamp the rod body to one of the mandrels of the mandrel assembly. Another force is applied to the rod cap to clamp the rod cap to the other mandrel of the mandrel assembly. The two mandrels of the mandrel assembly are then forced apart to separate the rod cap. All of these forces are applied in directions parallel to the connecting rod center line and are generally balanced about the center line. There are no intentional bending moments on the connecting rod web. The mandrel assembly absorbs any force exerted on the crank shaft end of a connecting rod that is transverse to the connecting rod center line. The assembly that applies force to the wrist pin end of a connecting rod absorbs any forces on the wrist pin end of the connecting rod that are transverse to the connecting rod center line and hold the wrist pin end in a substantially fixed position.

There are also rod cap cracking machines that employ four or more clamping surfaces to fix the connecting rod crankshaft end. With these machines the wrist pin end of the connecting rod is free to float parallel to the connecting rod axis. The wrist pin end is also free to flow transverse to the connecting rod center line in some of the rod cracking machines that have four or more surfaces controlling movement of the crankshaft end. SUMMARY OF THE INVENTION

The connecting rod fracturing machine has a frame. A mandrel assembly includes a first mandrel portion fixed to the frame and a second mandrel portion carried by a carriage. The carriage is slidably mounted on the frame for movement toward and away from the first mandrel portion along a carriage axis that is perpendicular to a rod cap cracking plane. A hydraulic cracking actuator, supported by the frame, moves the second mandrel portion along the carriage axis and away from the first mandrel portion. A first clamp assembly mounted on the carriage of the mandrel assembly, has a clamp member with at least two spaced apart rod cap contact surfaces. A first clamp assembly actuator moves the clamp member toward the second mandrel portion. A pair of wrist pin end clamp members are mounted on the frame. These end clamps include at least one wrist pin end clamp actuator that acts along a wrist pin clamp axis that is perpendicular to a connecting rod center line that intersects the rod cap cracking plane at an acute angle. A crankshaft end clamp has an actuator that contacts a connecting rod crankshaft end and exerts force on a connecting rod along a crankshaft end clamp axis. The crankshaft end clamp axis passes through the mandrel axis and intersects the rod cap cracking plane at an acute angle. The connecting rod fracturing machine permits the separation of a rod cap from a rod body along a rod cracking plane that is intersected by a connecting rod center line at an acute angle.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein: Figure 1 is a front elevational view of a rod cracking machine with part of the mandrel assembly broken away; and Figure 2 is a side elevational view of the rod cracking machine with parts broken away.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The connecting rod fracturing or cracking machine

10 has a frame 12 with a base 14 (partially shown) , a horizontal plate 16, a lower vertical plate 18 and an upper vertical plate 20. The terms vertical, horizontal, upper and lower describe the rod cracking machine 10 as shown in the drawing. During use of the rod cracking machine 10, the connecting rod 22 can be vertical as shown, horizontal, switched end for end, or held at any other orientation. The lower vertical plate 18 is secured to the base 14 and the horizontal plate 16. The upper vertical plate 20 is secured to the horizontal plate 16 and is reinforced by gussets 24. A pair of spaced apart L-shaped guide rails 26 and 28 are secured to the upper vertical plate 20 by bolts 30. A lower block 32 has vertical grooves 34 and 36 that receive portions of the rails 26 and 28 to horizontally fix the lower block 32. The lower block 32 is also secured to the horizontal plate 16 by bolts 38.

An upper carriage 40 has vertical grooves 42 and 44 that receive portions of the rails 26 and 28. The rails 26 and 28 confine the carriage 40 to vertical movement along a carriage axis 52 toward and away from the lower block 32. An air cylinder 46 is mounted on a support plate 48 of a bracket 50. The bracket 50 is clamped to the upper vertical plate 20. A rod 54 of the air cylinder 46 is connected to the carriage 40. A mandrel assembly 56 includes a first mandrel half 58 and a second mandrel half 60. The first mandrel half 58 is clamped to the lower block 32. Bolts 62 also clamp the first mandrel half 58 to the horizontal plate 16. The second mandrel half 60 is clamped to the carriage 40.

The first mandrel half 58 includes a wedge passage 64. The second mandrel half 60 includes a wedge passage 66. A wedge 65 is slidably mounted in the cooperating wedge passages 64 and 66. A piston rod 67 of a hydraulic cylinder 69 is connected to the wedge 65. The hydraulic cylinder 69 is pivotally attached to gussets 24 of the frame 12 by a shaft 70. Supplying hydraulic fluid under pressure to the hydraulic cylinder 69 through hydraulic lines (not shown) to extend the piston rod 67 moves the wedge member 65 to the left as shown in Figure 1. Moving the wedge member 65 to the left forces the second mandrel half 60 upward and away from the first mandrel half 58. The upper carriage 40 is raised with the second mandrel half 60. Separation of the mandrel halves 58 and 60 of the mandrel assembly 56 fractures the crank shaft end 104 of the connecting rod 22 and separates the rod cap 68 from the connecting rod body 126. The wedge 65 and the hydraulic cylinder 69, as described above, function as a fracturing actuator. The wedge 65 for separating the mandrel halves 58 and 60 is employed on some production connecting rod fracturing machines. There are however other known devices for separating two mandrel halves 58 and 60. Many of the other known devices for separating two mandrel halves 58 and 60 can be used in place of the wedge 65 if desired.

A wedge clamp assembly 74 includes an inner plate 76 and an outer plate 78 that are clamped to the second mandrel half 60 and a carriage 40 by bolts 80. A vertical passage 82 between the inner plate 76 and the outer plate 78 slidably receive a wedge clamp member 84. The lower end of the wedge clamp 84 has spaced apart rod cap contact surfaces 86 and 88. An inclined groove 90 in the wedge clamp 84 receives an inclined bar 92 on a wedge lock 94. The wedge lock 94 is slidably mounted in a horizontal slot 96 in the inner plate 76. A hydraulic cylinder 98 is attached to a bracket 100 on one side of the inner plate 76 and the outer plate 78. The piston rod 102 of the hydraulic cylinder 98 is attached to the wedge lock 94.

Extending the piston rod 102 moves the wedge lock 94 to the right, as shown in Figure 1, and moves the wedge cla p 84 toward the second mandrel half 60. Retracting the piston rod 102 moves the wedge lock 94 to the left and moves the wedge clamp 84 away from the second mandrel half 60. The connecting rod 22 for an internal combustion engine has a crankshaft end 104 and a wrist pin end 106. The wrist pin end 106 and the crankshaft end 104 are joined to each other by a web 108. A connecting rod center line 110 passes through the wrist pin bore axis 112 and the crankshaft throw bore axis 114. The crankshaft bore axis 114 and the mandrel assembly axis are coaxial as shown in Figures 1 and 2. The connecting rod center line 110 intersects the rod cap cracking plane P at an acute angle of about 50° as shown in the drawing. This angle may vary between the connecting rods for one engine and the connecting rods for another engine.

A first wrist pin end clamp 116 and a second wrist pin end clamp 118 are clamped to the lower vertical plate 18 on opposite sides of the connecting rod 22 and the connecting rod center line 110. The first and second wrist pin clamps 116 and 118 include hydraulic cylinders and piston rods 120 and 122 that have a common center line 124. The common center line 124 is perpendicular to the connecting rod center line 110. The common center line 124 is also tangent to a circle with a center at the crankshaft throw bore axis 114. As shown in Figure l, the common center line 124 of the piston rods 120 and 122 also passes through the wrist pin bore axis 112. However, the piston rods 120 and 122 can be moved to other locations along the connecting rod center line 110 where there is a suitable connecting rod surface to which force can be applied. The purpose of the first wrist pin clamp 116 and the second wrist pin clamp 118 is to prevent rotation of the connecting rod body 126 about the crankshaft bore axis 114.

A crankshaft end clamp 128 is attached to the lower vertical plate 18 as shown in Figure 1. This clamp 128 is also a hydraulic cylinder with a piston rod 130. The piston rod 130 exerts force on the crankshaft end 104 of the connecting rod 22 that clamps the connecting rod body 126 against the first mandrel half 58. Force is applied along a line that passes through the crankshaft bore axis 114 and intersects the cracking plane P at an acute angle. After the rod cap 68 is separated from the connecting rod body 126 at the rod cap cracking plane P, the crankshaft end 104 of the connecting rod body 126 has a short arm 132 and a long arm 134. The purpose of the crankshaft end clamp 128 is to prevent bending of the long arm 134.

During operation of the connecting rod fracturing machine 10, the crankshaft end 104 of the connecting rod 22 is inserted over the first mandrel half 58 and the second mandrel half 60 of the mandrel assembly 56. The wrist pin end 106 of the connecting rod 22 is simultaneously positioned between the first and second wrist pin clamps 116 and 118. The rod 54 of the cylinder 46 is retracted to lift the second mandrel half 60 and preload the mandrel assembly 56. The first wrist pin clamp 116 and the second wrist pin clamp 118 are pressurized to fix the wrist pin end 106 of the connecting rod body 126. The crankshaft end clamp 128 is pressurized to clamp the long arm 134 to the first mandrel half 58. High pressure hydraulic fluid is then supplied to the hydraulic cylinder 64 to separate the second mandrel half 60 from the first mandrel half 58 and fracture the rod cap 68 from the connecting rod body 126.

A fixed stop member 140 secured to the support plate 48 is connected by a movable stop 142 carried by the carriage 40 to limit movement of the second mandrel half 60 away from the fixed first mandrel half 58.

Claims

What is claimed is: 1. A connecting rod fracturing machine comprising: a frame; a mandrel assembly including a first mandrel portion fixed to the frame and a second mandrel portion carried by a carriage that is slidably mounted on the frame for movement toward and away from the first mandrel portion along a carriage axis that is perpendicular to a rod cap fracturing plane; a fracturing actuator supported by the frame for moving the second mandrel portion along the carriage axis and away from the first mandrel portion; a first clamp assembly mounted on the carriage of the mandrel assembly and having a clamp member with at least two spaced apart rod cap contact surfaces and a first clamp assembly actuator that moves the clamp member toward the second mandrel portion; a pair of wrist pin end clamp members mounted on the frame and including at least one wrist pin end clamp actuator that acts along a wrist pin clamp axis which is perpendicular to a connecting rod center line that intersects the rod cap fracturing plane at an acute angle; and a crankshaft end clamp having an actuator that contacts a connecting rod crankshaft end and exerts force on a connecting rod along a crankshaft end clamp axis that passes through a mandrel axis and intersects the rod cap fracturing plane at an acute angle.

2. A connecting rod fracturing machine as set forth in claim 1 wherein the clamp member of the first clamp assembly is moved toward the second mandrel portion by a wedge.

3. A connecting rod fracturing machine as set forth in claim 2 wherein the clamp member of the first clamp assembly is moved away from the second mandrel portion by the wedge.

4. A connecting rod fracturing machine as set forth in claim 1 wherein the pair of wrist pin end clamp members include a second wrist pin end clamp actuator that acts along the wrist pin clamp axis in the opposite direction from the at least one wrist pin end clamp actuator.

5. A connecting rod fracturing machine as set forth in claim 1 wherein the first clamp assembly actuator includes a wedge lock with an inclined bar and a hydraulic cylinder that advances the wedge lock to move the two spaced apart rod cap contact surfaces toward the second mandrel portion.

6. A connecting rod fracturing machine as set forth in claim 1 wherein the pair of wrist pin end clamp members includes another wrist pin end clamp actuator that acts along the wrist pin clamp axis in the opposite direction from the at least one wrist pin clamp actuator.

7. A connecting rod fracturing machine as set forth in claim 1 wherein the crankshaft end clamp includes a hydraulic cylinder.

8. A connecting rod racturing machine comprising: a frame; a mandrel assembly including a first mandrel portion fixed to the frame and a second mandrel portion carried by a carriage that is slidably mounted on the frame for movement toward and away from the first mandrel portion along a carriage axis that is perpendicular to a rod cap fracturing plane; a hydraulic fracturing actuator supported by the frame for moving the second mandrel portion along the carriage axis and away from the first mandrel portion; a wedge clamp assembly mounted on the carriage of the mandrel assembly and having a wedge clamp member slidably mounted for movement perpendicular to the fracturing plane, a wedge lock slidably mounted for movement relative to the wedge clamp member, and an actuator that moves the wedge lock and moves the wedge clamp into engagement with a rod cap and clamps the. rod cap to the second mandrel portion; a first wrist pin end clamp mounted on the frame and including a first hydraulic actuator with a first clamp piston rod that acts along a wrist pin clamp axis which is perpendicular to a connecting rod center line that intersects the rod cap plane at an acute angle; a second wrist pin end clamp mounted on the frame and including a second hydraulic actuator spaced from the first hydraulic actuator, with a second clamp piston rod that is coaxially with the first clamp piston rod and acts in the opposite direction from the first clamp piston rod; and a crankshaft end clamp having a crankshaft end hydraulic actuator with a crankshaft piston rod having a crankshaft piston rod axis that intersects a crankshaft bore axis and wherein the crankshaft end hydraulic actuator, when pressurized, clamps a connecting rod body to the first mandrel portion.

9. A method of fracturing a connecting rod having a crankshaft end bore and a wrist pin end bore, a crankshaft bore axis, a wrist pin bore axis, a connecting rod center line that passes through the crankshaft bore axis and the wrist pin bore axis, a rod cap, a rod body, and a rod fracture plane that intersects the center line at an acute angle comprising: inserting a mandrel assembly having a first mandrel portion and a second mandrel portion into the crankshaft end bore; clamping the rod cap to the second mandrel portion; blocking pivotal movement of the rod cap about the crankshaft bore axis; applying a first force to the wrist pin end of the rod body along a first line that is perpendicular to the connecting rod center line and that intersects the rod fracture plane, to prevent pivotal movement of the rod body about the crankshaft bore axis in a first direction; applying a second force to the wrist pin end of the rod body along a second line that is perpendicular to the connecting rod center line and that intersects the rod fracture plane to prevent pivotal movement of the rod body about the crankshaft bore axis in a second direction; and applying a third force to the crankshaft end of the rod body along a third line that passes through the crankshaft bore axis and clamps the rod body to the first mandrel portion; and applying sufficient force to separate the second mandrel portion from the first mandrel portion thereby fracturing the rod cap along the rod fracture plane.

10. A method of fracturing a connecting rod as set forth in claim 9 wherein the first line and the second line, along which the first force and the second force are applied, are coaxial.