WO1990004471A1 - Nose assembly for pulling fasteners through interference fit holes - Google Patents
Nose assembly for pulling fasteners through interference fit holes Download PDFInfo
- Publication number
- WO1990004471A1 WO1990004471A1 PCT/US1989/003948 US8903948W WO9004471A1 WO 1990004471 A1 WO1990004471 A1 WO 1990004471A1 US 8903948 W US8903948 W US 8903948W WO 9004471 A1 WO9004471 A1 WO 9004471A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- jaw
- collet
- nose assembly
- jaws
- anvil
- Prior art date
Links
- 230000000694 effects Effects 0.000 claims 1
- 241001136800 Anas acuta Species 0.000 description 18
- 230000004323 axial length Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- 238000005452 bending Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J15/00—Riveting
- B21J15/02—Riveting procedures
- B21J15/022—Setting rivets by means of swaged-on locking collars, e.g. lockbolts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B4/00—Shrinkage connections, e.g. assembled with the parts at different temperature; Force fits; Non-releasable friction-grip fastenings
- F16B4/004—Press fits, force fits, interference fits, i.e. fits without heat or chemical treatment
Definitions
- This invention relates generally to an apparatus for pulling fastener pins through a workpiece and particularly relates to a nose assembly having a set of internally-supported spring-biased jaws for engaging a series of pull grooves formed on the fastener pins.
- Pin and collar fasteners of the lock bolt variety are commonly used to fabricate various frames and structures including aircraft wings and aircraft cabins. It is often desirable to produce an interference fit between the body of the pin and the members being fastened in order to produce a fatigue resistant joint by cold working the material surrounding the pin. This is particularly advantageous in the case of a fabrication requiring a leak-tight assembly such as an aircraft wing which also serves as a fuel tank, or an aircraft cabin which is subject to pressurization. While an interference fit can be clearly desirable in numerous applications, there has been a most undesirable problem associated with the use of an interference fit between a fastener pin and its surrounding structure.
- J stringers structural channel members
- the present invention has been developed to meet the needs noted above and therefore has as a primary object the provision of a nose assembly adapted for use with a pneumatic or hydraulic tool for pulling fasteners through an interference fit while generating negligible levels of noise.
- the nose assembly of the present invention is provided with a set of gripping jaws which are adapted project axially outwardly from a collet member as an axial pulling force is applied to the pin.
- the jaws are adapted to project from the collet and thereby lose the support they would otherwise receive if completely nested within the collet, they must be provided with extra radial support. This extra support prevents the jaws from being damaged or pulled completely out of the collet as they pull a fastener pin through an interference fit within a bore or hole. Extra radial support is obtained by providing a recess in the rear of the jaws and fitting a support member or jaw follower within the recess to prevent the rear portion of the jaws from radially collapsing under the applied loads.
- the jaws, anvil and j.aw follower are provided with complimentary conical surfaces to create a radially directed wedge-like camming action.
- a biasing member such as a compression spring maintains a constant axial force on the jaw follower which in turn transfers this force to the jaws to ensure that the jaws are advanced axially forwardly within the collet prior to gripping the fastener.
- This design guarantees the greatest' axial engagement possible between the jaws and the fastener prior to tool actuation and maintains axially biased contact between the jaw follower and jaws. This contact is required to provide radial support to the rear portions of the jaws to counter the bending moments created at the front of the jaws thereby improving the reliability of the nosepiece.
- the present invention eliminates a release or ejector assembly commonly used in prior nosepiece designs in order to axially advance the jaws as far forward as possible to provide the maximum amount of axial engagement between the jaws and the fastener.
- the jaws can receive the maximum radial support available from the fastener and promote full engagement between the jaw teeth and fastener.
- the jaws project forwardly from the collet to allow them to engage as much of the fastener as possible, the jaws are provided additional support from a jaw follower to prevent their radial collapse about their rear skirted portions.
- Figure 1 is an axial cross section view through a prior art nose assembly used to swage collar members over fastener pins;
- Figure 2 is an exploded perspective view of a nose assembly according to the present invention
- Figure 3 is an axial cross section view through a nose assembly according to the present invention as mounted to a tool;
- Figures 4-6 are axial cross section views of the nose assembly of Figure 3 shown in various sequential stages of operation.
- Figure 7 is a fragmental sectional view showing partial engagement of the chuck jaws with a fastener member.
- Nose assembly 1 is adapted for use with pin and collar type fasteners of the lock bolt variety wherein a cylindrical collar is swaged into axially spaced annular grooves formed along the shank of a fastener pin. Swaging is carried out by engaging a pintail 3 of a fastener pin 5 within chuck jaws 7 and applying an axial reward force through spindle 9 and collet 11. Axial pulling and ejecting forces may be provided with a conventional reciprocating pneumatic tool 12 such as shown in fragment in Figure 3.
- the anvil 17 In order to perform the swaging, the anvil 17 must be formed with an axially extending contoured swaging surface 23 which radially squeezes and deforms the collar 19 into the grooves 21 in the pin 5. Because of the high forces generated during this swaging operation, swaging surface 23 must be reinforced with relatively thick and massive anvil material sections 25. Anvil sections 25 extend over a significant axial distance A thereby requiring the pintail 3 to axially extend within the nose assembly over this distance before engaging the chuck jaws 7.
- a release ejector assembly 27 is located between and partially within the collet 11 and anvil 17.
- a press-fit tubular spacer 31 forming a portion of the release ejector 27 displaces the jaws axially rearwardly within the collet 11. Release is achieved by driving the collet 11 forwardly causing the annular leading edge 29 of ejector 27 to contact the axial end face 30 of swaged collar 19 and push the nose assembly 1 away from the collar thereby freeing surface 23 from tight frictional engagement with the collar.
- the chuck jaws 7 are axially spaced or recessed within the nose assembly a considerable distance from the end face 33 of the anvil. This spacing is equal to the sum of the axial length A of the anvil 17 and the axial length B of the release ejector 27 which includes the full axial length of the spacer 31.
- nose assembly 35 includes an anvil housing 37 adapted to be mounted on the end of pneumatic assembly tool 12 via threaded retaining nut 39.
- An internally threaded spindle 43 is adapted to be threaded to the end of tool piston 44 for powered linear reciprocating movement.
- a split ring 46 accurately positions and spaces the anvil housing 37 on the tool.
- a collet 45 is threaded to the forward end of the spindle 43 to receive the axially directed actuating force from the tool piston.
- a jaw follower member 47 includes a rearwardly projecting locating boss 49 which coaxially nests within a central longitudinal bore 51 formed through the spindle 43.
- the jaw follower 47 further includes a radially projecting flange 53 having a front face 55 and a rear face 57.
- a biasing element such as compression spring 59 is coaxially mounted over the cylindrical body portion of the jaw follower 47 and is bounded between the rear face 57 of flange 53 and the front end face 61 of the spindle.
- Spring 59 applies an axial force to the jaw follower 47 which in turn transfers this force to the three-piece circumferentially-segmented chuck jaws 63 via the front face 55 of flange 53.
- Complimentary conical surfaces are formed on the rear face 65 of each chuck jaw segment and the front face 55 of flange 53.
- Conical front face 55 projects within a conical recess defined by the rear faces 65 of each chuck jaw segment.
- Most essential are the complimentary conical surfaces formed on the interior face 67 of anvil 69 and the front face 71 of each jaw segment 63. These complimentary surfaces 67, 71 are required for effecting a consistent release of the jaws from the fastener.
- Surfaces 55 and 65 further aid in the camming action.
- the cone angle X between faces 55 and 65 and the cone angle Y between faces 67 and 71 are each fixed at approximately 10 degrees. However, angle X is directed axially rearwardly from a pure radial direction while angle Y is directed axially forwardly from a pure radial direction.
- This arrangement provides for a radially outwardly camming action upon each chuck jaw segment 63. The camming action is generated between faces 55 and 65 as well as faces 67 and 71 when an axial "squeezing" force is applied via flange 53 of jaw follower 47.
- each chuck jaw segment 63 is nested virtually completely within the interior conical portion 73 of collet 45.
- each chuck jaw segment 63 In this position, the front face 71 of each chuck jaw segment 63 is maintained in abutment with interior face 67 of anvil 37 by mounting the nose assembly to the tool.
- This mounting compresses spring 59 as discussed above and a radially outwardly wedging action is thus applied to each chuck jaw segment thereby maintaining the chuck jaws in the "open” or radially expanded or spread apart state shown in Figure 3.
- a cavity 91 ( Figure 4) is formed in the front of follower 47 to allow full penetration of the pintail 3 within the chuck jaws 63.
- the cavity 91 is deep enough to allow the full length of the pintail to be received therein, yet is shallow enough to prevent any engagement of the jaws with the locking grooves 90.
- the chuck jaws 63 begin to axially pull the fastener pin 5 through the interference fit hole 4.
- the chuck jaws 63 experience a bending moment applied around the inner front edge 99 of the collet 45 ( Figure 5) .
- This bending moment is accompanied by a force which tends to pull the chuck jaw segments out of the front of collet 45, as represented by arrows 101.
- This moment arid force are countered by the radial support provided between boss 89 and jaw skirt 77.
- the tool piston may be powered in reverse to produce a very small reaction force against the pintail 3 which results in the anvil 45 retracting from the workpieces 106, 108 as shown in Figure 6.
- the front face 105 of the collet 45 directly confronts the inside face 67 of the anvil so as to allow the chuck jaws 63 to expand radially outwardly under the radially camming or wedging action discussed above.
- the nose assembly 35 may be freely removed from the pintail 3 and freely positioned over another fastener to repeat the pulling operation.
- a collar 19 may be placed over the pin and swaged in place with a nose assembly such as shown in Figure 1.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Insertion Pins And Rivets (AREA)
Abstract
A nose assembly (1) for pulling fasteners (5, 19) through a workpiece (106, 108) includes an anvil (17) having a conical surface (67) for engaging a complimentary conical surface (71) defined by a set of chuck jaws (63). The chuck jaws (63) include a rear skirted portion (77) defining a recess for receiving a biased support member (89) which prevents the radial collapse of the chuck jaws (63) during actuation of the nose assembly (1). The nose assembly (1) is particularly adapted for gripping a relatively short axially projecting portion (3) of a fastener (5) while ensuring complete engagement of all jaw teeth with the fastener (5).
Description
NOSE ASSEMBLY FOR PULLING FASTENERS THROUGH INTERFERENCE FIT HOLES
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates generally to an apparatus for pulling fastener pins through a workpiece and particularly relates to a nose assembly having a set of internally-supported spring-biased jaws for engaging a series of pull grooves formed on the fastener pins.
Description of Prior Developments
Pin and collar fasteners of the lock bolt variety are commonly used to fabricate various frames and structures including aircraft wings and aircraft cabins. It is often desirable to produce an interference fit between the body of the pin and the members being fastened in order to produce a fatigue resistant joint by cold working the material surrounding the pin. This is particularly advantageous in the case of a fabrication requiring a leak-tight assembly such as an aircraft wing which also serves as a fuel tank, or an aircraft cabin which is subject to pressurization. While an interference fit can be clearly desirable in numerous applications, there has been a most undesirable problem associated with the use of an interference fit between a fastener pin and its surrounding structure.
In order to produce such an interference fit, it has been necessary to use a hammer or an air impact tool to force the fastener pin through a hole formed through each member being fastened. This hammering has resulted in excessive noise levels reaching up to 120 decibels. Hammering poses a threat to hearing and requires the use of ear protection. Another drawback associated with such hammering is that it often
damages the head of the fastener pin and/or the members being fastened.
Setting fasteners by conventional techniques requires one assembler to initially position the pin through one exposed side of the workpiece and subsequently hammer the pin therethrough while a second assembly worker applies reinforcing support to the opposite side of the workpiece via a bucking bar. Thus, two workers are needed to carry out this labor intensive task using conventional methods.
Prior to the present invention, no tool was available which could adequately grip the relatively short axial length of the fastener pin which projected through the members or workpieces being fastened. That is, a portion of the end of the fastener pin opposite its head is typically of reduced radial section to allow that section of the pin to be freely inserted through the members being fastened. This exposes a short axial portion of the fastener prior to reaching the point of interference between a radially enlarged portion of the pin shank and the opposite or back face of the structure being fastened.
Of course, it is possible to make the non-interference fit portion of the fastener pin longer to provide a longer gripping surface. However, this results in considerable expense and material waste since this portion, which is commonly known as a pintail, is broken off and discarded when a collar or nut is subsequently swaged or fastened over the pin. This poses a particular problem in aircraft applications since the material used for the fastener pins in such applications is frequently titanium which is quite expensive.
Moreover, it is often not possible to use long fastener pins due to space limitations which prevent a fastener tool from accessing the elongated fastener pins. This is particularly true in the case of aircraft applications where
structural channel members known as "J stringers" prevent the fastener tool from reaching and engaging those fastener pins located within the J-stringer channels.
Accordingly, a need exists for a reliable nose assembly for use with a low noise level tool capable of gripping a short axial length of a fastener pin and quietly and smoothly pulling the fastener pin through an interference fit hole without damaging the fastener pin or the workpieces being fastened.
SUMMARY OF THE INVENTION
The present invention has been developed to meet the needs noted above and therefore has as a primary object the provision of a nose assembly adapted for use with a pneumatic or hydraulic tool for pulling fasteners through an interference fit while generating negligible levels of noise. In order to securely grip the typically short axial length of the fastener which projects through an interference hole, the nose assembly of the present invention is provided with a set of gripping jaws which are adapted project axially outwardly from a collet member as an axial pulling force is applied to the pin.
Because the jaws are adapted to project from the collet and thereby lose the support they would otherwise receive if completely nested within the collet, they must be provided with extra radial support. This extra support prevents the jaws from being damaged or pulled completely out of the collet as they pull a fastener pin through an interference fit within a bore or hole. Extra radial support is obtained by providing a recess in the rear of the jaws and fitting a support member or jaw follower within the recess to prevent the rear portion of the jaws from radially collapsing under the applied loads.
In order to radially expand and contract the jaws to respectively release and grip the fastener, the jaws, anvil and j.aw follower are provided with complimentary conical surfaces
to create a radially directed wedge-like camming action. A biasing member such as a compression spring maintains a constant axial force on the jaw follower which in turn transfers this force to the jaws to ensure that the jaws are advanced axially forwardly within the collet prior to gripping the fastener. This design guarantees the greatest' axial engagement possible between the jaws and the fastener prior to tool actuation and maintains axially biased contact between the jaw follower and jaws. This contact is required to provide radial support to the rear portions of the jaws to counter the bending moments created at the front of the jaws thereby improving the reliability of the nosepiece.
The presence of a fastener within the jaws prevents the jaws from radially collapsing. Should the jaws radially collapse, they could be pulled completely out of the collet or otherwise damaged. This is a particularly common occurrence with prior nosepieces when only a short length of fastener is accessible. Moreover, the greater the axial length of engagement between the fastener and the jaws, the less will be the extent of non-engaged and unsupported jaw teeth.
The present invention eliminates a release or ejector assembly commonly used in prior nosepiece designs in order to axially advance the jaws as far forward as possible to provide the maximum amount of axial engagement between the jaws and the fastener. In this manner, the jaws can receive the maximum radial support available from the fastener and promote full engagement between the jaw teeth and fastener. However, since the jaws project forwardly from the collet to allow them to engage as much of the fastener as possible, the jaws are provided additional support from a jaw follower to prevent their radial collapse about their rear skirted portions.
By axially biasing the jaws within the collet, the probability of complete engagement of all jaw teeth with the fastener is increased under normal assembly conditions. If
less than all jaw teeth engage the fastener, those teeth which are engaged are required to carry the entire pulling load thereby increasing the actual load on each engaged jaw tooth. Engagement of only one or two jaw teeth generates a radial twisting action or bending moment about the tip of the jaws and tends to pull the jaws radially outwardly from the collet. This condition, which is avoided by the present invention, can result in bent or deformed jaw teeth and jaws.
Brief Description of the Drawings
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings wherein:
Figure 1 is an axial cross section view through a prior art nose assembly used to swage collar members over fastener pins;
Figure 2 is an exploded perspective view of a nose assembly according to the present invention;
Figure 3 is an axial cross section view through a nose assembly according to the present invention as mounted to a tool;
Figures 4-6 are axial cross section views of the nose assembly of Figure 3 shown in various sequential stages of operation; and
Figure 7 is a fragmental sectional view showing partial engagement of the chuck jaws with a fastener member.
Detailed Description of the Preferred Embodiments
In order to better appreciate the merits of the present invention, a brief review of a prior art nose assembly such as shown in Figure 1 may be useful. Nose assembly 1 is adapted for use with pin and collar type fasteners of the lock bolt variety wherein a cylindrical collar is swaged into axially spaced annular grooves formed along the shank of a fastener pin. Swaging is carried out by engaging a pintail 3 of a fastener pin 5 within chuck jaws 7 and applying an axial reward force through spindle 9 and collet 11. Axial pulling and ejecting forces may be provided with a conventional reciprocating pneumatic tool 12 such as shown in fragment in Figure 3.
As collet 11 is pulled rearwardly, its conical camming surface 13 engages the conical outer contour 15 of the chuck jaws 7 thereby causing the chuck jaws to radially contract and engage the grooves and ridges of the pintail 3. As the collet 11 continues rearwardly, the chuck jaws 7 axially pull the pintail 3 rearwardly causing the anvil 17 to engage the collar 19 with a reactionary force and swage the collar into the grooves 21 on the pin 5.
In order to perform the swaging, the anvil 17 must be formed with an axially extending contoured swaging surface 23 which radially squeezes and deforms the collar 19 into the grooves 21 in the pin 5. Because of the high forces generated during this swaging operation, swaging surface 23 must be reinforced with relatively thick and massive anvil material sections 25. Anvil sections 25 extend over a significant axial distance A thereby requiring the pintail 3 to axially extend within the nose assembly over this distance before engaging the chuck jaws 7.
In order to free the nose assembly after swaging, a release ejector assembly 27 is located between and partially
within the collet 11 and anvil 17. A press-fit tubular spacer 31 forming a portion of the release ejector 27 displaces the jaws axially rearwardly within the collet 11. Release is achieved by driving the collet 11 forwardly causing the annular leading edge 29 of ejector 27 to contact the axial end face 30 of swaged collar 19 and push the nose assembly 1 away from the collar thereby freeing surface 23 from tight frictional engagement with the collar.
It can be seen that the chuck jaws 7 are axially spaced or recessed within the nose assembly a considerable distance from the end face 33 of the anvil. This spacing is equal to the sum of the axial length A of the anvil 17 and the axial length B of the release ejector 27 which includes the full axial length of the spacer 31.
While this spacing is acceptable for use with relatively long pintails, the axial spacing of A+B is too great to permit engagement of the chuck jaws with the relatively short pintails associated with aircraft fabrications. Short pintails are typically associated with fasteners designed and specified for minimizing material waste and material cost, for reducing material weight and for facilitating their access by increasing the clearance available for installation tooling. In order to access and engage the limited available gripping length of the pintail designed for such applications, the nose assembly of Figures 2-7 has been developed according to the present invention.
As seen in Figures 2 and 3, nose assembly 35 includes an anvil housing 37 adapted to be mounted on the end of pneumatic assembly tool 12 via threaded retaining nut 39. An internally threaded spindle 43 is adapted to be threaded to the end of tool piston 44 for powered linear reciprocating movement. A split ring 46 accurately positions and spaces the anvil housing 37 on the tool.
A collet 45 is threaded to the forward end of the spindle 43 to receive the axially directed actuating force from the tool piston. A jaw follower member 47 includes a rearwardly projecting locating boss 49 which coaxially nests within a central longitudinal bore 51 formed through the spindle 43. The jaw follower 47 further includes a radially projecting flange 53 having a front face 55 and a rear face 57.
A biasing element such as compression spring 59 is coaxially mounted over the cylindrical body portion of the jaw follower 47 and is bounded between the rear face 57 of flange 53 and the front end face 61 of the spindle. Spring 59 applies an axial force to the jaw follower 47 which in turn transfers this force to the three-piece circumferentially-segmented chuck jaws 63 via the front face 55 of flange 53.
Complimentary conical surfaces are formed on the rear face 65 of each chuck jaw segment and the front face 55 of flange 53. Conical front face 55 projects within a conical recess defined by the rear faces 65 of each chuck jaw segment. Most essential are the complimentary conical surfaces formed on the interior face 67 of anvil 69 and the front face 71 of each jaw segment 63. These complimentary surfaces 67, 71 are required for effecting a consistent release of the jaws from the fastener. Surfaces 55 and 65 further aid in the camming action. By forming surface 67 on the interior face of the anvil and surface 71 on the front face of each jaw segment, the release ejector assembly 27 of Figure 1 may be eliminated.
The cone angle X between faces 55 and 65 and the cone angle Y between faces 67 and 71 are each fixed at approximately 10 degrees. However, angle X is directed axially rearwardly from a pure radial direction while angle Y is directed axially forwardly from a pure radial direction. This arrangement provides for a radially outwardly camming action upon each chuck jaw segment 63. The camming action is generated between
faces 55 and 65 as well as faces 67 and 71 when an axial "squeezing" force is applied via flange 53 of jaw follower 47.
The force for this camming action is provided upon assembly of the nosepiece to the tool. In Figure 4, the anvil housing and spindle are represented in their relative positions under which spring 59 is in its uncompressed configuration. As seen in Figure 3, before tool actuation, the rear end face 70 of the anvil housing 37 is aligned in the same radial plane as the end face 72 of spindle 43. This alignment results in the compression spring 59 and the application of an axial pinching of the jaws. This pinching causes the jaws 63 to cam radially outwardly to freely receive a fastener. The amount of spring compression achieved during assembly can be seen by the difference in axial alignment between end faces 70 and 72 as shown in Figure 4.
The operation of the nose assembly may be better appreciated from the actuation sequence shown in Figures 3-6. The nose assembly shown in Figure 3 is in an unactuated or power-off condition such as occurs just before air or hydraulic power is applied to the tool to pull the spindle, collet, jaw follower, spring and chuck jaws axially rearwardly. In this free state, each chuck jaw segment 63 is nested virtually completely within the interior conical portion 73 of collet 45.
In this position, the front face 71 of each chuck jaw segment 63 is maintained in abutment with interior face 67 of anvil 37 by mounting the nose assembly to the tool. This mounting compresses spring 59 as discussed above and a radially outwardly wedging action is thus applied to each chuck jaw segment thereby maintaining the chuck jaws in the "open" or radially expanded or spread apart state shown in Figure 3.
When the chuck jaws are biased open in the at rest condition in Figure 3, the radial outer surface 75 of the rear tubular skirted portion 77 of each chuck segment -63 is wedged
radially outwardly to contact the inner wall 79 of the cylindrical bore 81 formed within collet 45. This increases the clearance within the chuck jaws by an amount sufficient to allow the chuck jaws to be freely positioned over the fastener pintail 3. The amount of radial movement of the chuck jaws is set by the amount of radial clearance 83 (Figure 3) provided between the inner cylindrical wall 85 (Figure 4) of skirt 77 and the outer wall 87 of cylindrical boss 89.
A cavity 91 (Figure 4) is formed in the front of follower 47 to allow full penetration of the pintail 3 within the chuck jaws 63. The cavity 91 is deep enough to allow the full length of the pintail to be received therein, yet is shallow enough to prevent any engagement of the jaws with the locking grooves 90. After the nose assembly 35 has been freely positioned over the pintail as shown in Figure 3, power is applied by the tool 12 to axially retract the spindle 43 and collet 45.
During an initial portion of collet retraction (as shown in Figure 4 with the tool being removed for clarity) , the chuck jaws 63, follower 47 and the front face of the compression spring 59 remain virtually axially fixed in place although a small amount of movement is experienced by the chuck jaw segments 63 as they are cammed axially rearwardly via sliding contact between conical surfaces 67 and 71. This initial retraction causes each chuck jaw segment 63 to be wedged or cammed radially inwardly over the extent of radial clearance 83. This movement is caused ±>y the radial force applied to the chuck jaws via the camming action created by sliding contact between the conical inner surface 73 of the collet and the conical outer surface 93 of each chuck jaw segment 63.
The initial retraction of the collet forces the chuck jaw segments 63 into firm engagement with each mating ridge and groove formed on the pintail 3 as further shown in Figure 4. Engagement of each jaw tooth 95 with the pintail 3 provides radial support to the chuck jaws 63. Additional radial support
is provided by contact between inner wall 85 of jaw skirt 77 and the outer cylindrical wall 87 of follower boss 89.
Once this contact is made between the follower boss 89 and the jaw skirt 77, the chuck jaws 63 begin to axially pull the fastener pin 5 through the interference fit hole 4. As the pin 5 is pulled through the hole 4 the chuck jaws 63 experience a bending moment applied around the inner front edge 99 of the collet 45 (Figure 5) . This bending moment is accompanied by a force which tends to pull the chuck jaw segments out of the front of collet 45, as represented by arrows 101. This moment arid force are countered by the radial support provided between boss 89 and jaw skirt 77.
If less than all jaw teeth 95 are engaged with the pintail as shown in Figure 7, the likelihood of the jaws being pulled out of the collet is increased. Thus, by locating the chuck jaw teeth as close as possible to the front face 103 of the anvil 104, full engagement of each tooth is ensured, thereby minimizing the chance of pulling the chuck jaws out of the collet. Moreover, even if less than all the chuck jaw teeth are engaged with the fastener, the radial support provided by boss 89 prevents the jaws from radially collapsing or pivoting radially inwardly along the jaw skirt 77.
Once the head 6 of the pin 5 engages the back surface 102 of workpiece panel 106 (Figure 5) , the tool piston may be powered in reverse to produce a very small reaction force against the pintail 3 which results in the anvil 45 retracting from the workpieces 106, 108 as shown in Figure 6. At this point, the front face 105 of the collet 45 directly confronts the inside face 67 of the anvil so as to allow the chuck jaws 63 to expand radially outwardly under the radially camming or wedging action discussed above. In this position, the nose assembly 35 may be freely removed from the pintail 3 and freely positioned over another fastener to repeat the pulling operation.
Once the pin 5 is pulled through the interference hole 109 and nose assembly 35 released, a collar 19 may be placed over the pin and swaged in place with a nose assembly such as shown in Figure 1.
Obviously numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Claims
1. A nose assembly for pulling fasteners and the like through a workpiece, comprising:
a housing having an anvil for abutting a workpiece;
a collet operatively associated with said housing;
jaw means operatively associated with said collet for gripping said fasteners; and
support means operatively associated with said jaw means for radially supporting said jaw means against radially inwardly directed movement during said pulling.
2. The assembly of claim 1, further comprising biasing means for axially biasing said support means toward said jaw means.
3. The assembly of claim 1, wherein said jaw means comprises a recess defined within a rear portion thereof, and wherein said support means comprises a projection fitted within said recess.
4. The assembly of claim 1, wherein said anvil comprises first cam means for radially spreading said jaw means to facilitate entry of said fastener therein.
5. The assembly of claim 1, wherein said jaw means comprises second cam means for engaging said first cam means to effect said spreading of said jaws. -14-
6. A nose assembly for pulling fasteners and the like through a workpiece, comprising:
a housing having an anvil for abutting a workpiece;
a collet operatively associated with said housing;
jaw means operatively associated with said collet for gripping said fasteners; and
cam means fixed within said housing and confronting a front face of said jaw means for radially spreading said jaw means.
7. The nose assembly of claim 1, wherein said cam means is provided on said anvil.
8. The nose assembly of claim 1, further comprising biasing means for biasing said jaw means against said cam means.
9. The nose assembly of claim 1, further comprising support means located within said housing for supporting said jaw means against inwardly directed movement during said pulling.
10. The nose assembly of claim 1, wherein said cam means comprises a conical surface formed on an internal face of said anvil and further comprises a complimentary conical surface defined by said jaw means.
11. A nose assembly for pulling fasteners and the like through a workpiece, comprising:
a housing having an anvil for abutting a workpiece;
a collet operatively associated with said housing; jaw means operatively associated with said collet for gripping said fasteners; and
cam means for engaging a front face of said jaw means at a point axially forwardly of said collet.
12. The nose assembly of claim 11, wherein said cam means is located within said housing and wherein said jaw means is adapted to project axially forwardly of said collet.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE1989606796 DE68906796T2 (en) | 1988-10-19 | 1989-09-11 | NOSE PIECE FOR PULLING FASTENERS THROUGH OVERLOCKING HOLES. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US25993888A | 1988-10-19 | 1988-10-19 | |
US259,938 | 1988-10-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1990004471A1 true WO1990004471A1 (en) | 1990-05-03 |
Family
ID=22987075
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1989/003948 WO1990004471A1 (en) | 1988-10-19 | 1989-09-11 | Nose assembly for pulling fasteners through interference fit holes |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0440672B1 (en) |
WO (1) | WO1990004471A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI477331B (en) * | 2013-08-09 | 2015-03-21 | Tranmax Machinery Co Ltd | Electromotive pull nail gun with pre - tensioned nail and its operation method |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3362211A (en) * | 1964-07-09 | 1968-01-09 | Huck Mfg Co | Tool construction |
FR1575838A (en) * | 1968-05-24 | 1969-07-25 | ||
US4347728A (en) * | 1979-05-30 | 1982-09-07 | Huck Manufacturing Company | Apparatus and system for setting fasteners |
US4598572A (en) * | 1985-02-04 | 1986-07-08 | Huck Manufacturing Company | Apparatus and gripping jaw assembly for setting fasteners |
WO1986005723A1 (en) * | 1985-04-01 | 1986-10-09 | Huck Manufacturing Company | Offset tool and cartridge nose assembly |
WO1987000098A1 (en) * | 1985-07-03 | 1987-01-15 | Huck Manufacturing Company | Lightweight, high-pressure fastener installation tool |
-
1989
- 1989-09-11 EP EP19890910727 patent/EP0440672B1/en not_active Expired - Lifetime
- 1989-09-11 WO PCT/US1989/003948 patent/WO1990004471A1/en active IP Right Grant
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3362211A (en) * | 1964-07-09 | 1968-01-09 | Huck Mfg Co | Tool construction |
FR1575838A (en) * | 1968-05-24 | 1969-07-25 | ||
US4347728A (en) * | 1979-05-30 | 1982-09-07 | Huck Manufacturing Company | Apparatus and system for setting fasteners |
US4598572A (en) * | 1985-02-04 | 1986-07-08 | Huck Manufacturing Company | Apparatus and gripping jaw assembly for setting fasteners |
WO1986005723A1 (en) * | 1985-04-01 | 1986-10-09 | Huck Manufacturing Company | Offset tool and cartridge nose assembly |
WO1987000098A1 (en) * | 1985-07-03 | 1987-01-15 | Huck Manufacturing Company | Lightweight, high-pressure fastener installation tool |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI477331B (en) * | 2013-08-09 | 2015-03-21 | Tranmax Machinery Co Ltd | Electromotive pull nail gun with pre - tensioned nail and its operation method |
Also Published As
Publication number | Publication date |
---|---|
EP0440672B1 (en) | 1993-05-26 |
EP0440672A1 (en) | 1991-08-14 |
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