United States Patent 1111 3,630,067
[72] In en or Jam Hens a 3,088,618 5/1963 Pickford 72/453 X Sutton Coldfield, England 3,254,522 6/1966 Elliott et al, 72/391 [21] Appl. No. 33,273 3,451,248 6/1969 Bell 72/391 [22] Filed Apr. 30, 1970 3,548,627 12/1970 Henshaw 72/409 X [45] Patented Dec. 38, 1971 FOREIGN PATENTS [73] Ass'gnee 665,207 1 1952 Great Britain .1 72/391 Priority y 3 690,174 4/1953 Great Britain 72/391 Great Britain 384,333 2/1965 swltzerland 72/391 [31] 23,895/69 Primary Examiner- Robert D. Baldwin Assistam Examiner-John E. Roethel Attorneys-Richard A. Wise, Richard B. Magley and Carl E.
[54] FLUID PRESSURE OPERATED HEAD FOR J h SETTING MANDREL RIVETS 4 Claims, 4 Drawing Figs.
ABSTRACT: A fluid pressure operated tool, is disclosed for [52] US. Cl 7222/;7/951l, semng blind rivets by pulling and breaking their mandrels In into IIIIIIIIIIIIIIIIII n 821! 9/05 addition to including means for ejectmg the spent mandrel B21d3l/06 portion, the rivet head has mechanism for ensuring that us mandrel gripping jaw close prior to exerting substantial man- [50] held of Search 23 32? drel tension, open at the end of the mandrel pulling stroke.
and allow reloading of the head with retention of the next mandrel rivet to be installed.
[56] References Cited UNITED STATES PATENTS 2,088,859 8/1937 Huck 72/391 X PATENTEOuEc28|sm 3,630,067
SHEET 1 [1F 2 lnvenlor James N/lenshazu By hi5 Attorney PATENIEB DEC28 um SHEEI 2 OF 2 FLUID PRESSURE OPERATED HEAD FOR SETTING MANDREL RIVETS CROSS-REFERENCE TO RELATED APPLICATION A copending application Ser. No. 824,946, filed May 15, I969 in the name of James N. Henshaw discloses a fastener inserting machine of the type in which a rivet head such as is disclosed herein has particular advantage.
BACKGROUND OF THE INVENTION Pull-to-set blind rivets commonly include a tubular rivet having a mandrel extending axially therein, the mandrel having an upsetting head larger than the rivet bore and a stem portion which is tensioned axially as the rivet is held against displacement to cause the blind end of the rivet to be upset.
Fluid pressure operated blind riveting tools have heretofore been provided wherein mandrel gripping jaws have tensioned and broken the mandrels, an example being the disclosure of U.S. Pat. No. 3,254,522, filed Jan. 29, 1964 in the name of R. M. Elliott. In order to provide a fully effective operating stroke in a tool of this type, however, it is highly desirable that the gripping jaws be prevented from sliding on a mandrel before it is tensioned, and that an expulsion of each broken off mandrel portion or other phase of an operating cycle not interfere with or retard reloading of the tool in its succeeding cycle. The present invention, while acknowledged to be of use broadly in wire tensioning mechanism, is particularly advantageous in a high production line employing a riveting machine of the sort disclosed in the above cited I-Ienshaw application.
SUMMARY OF THE INVENTION In view of the foregoing it is an object of this invention to provide an improved head for a riveter adapted to set mandrel rivets, the head to comprise mandrel gripping jaws, and fluid pressure mechanism for controlling the jaws whereby they effectively close at the beginning of a setting stroke and are automatically opened at the end of the stroke to permit rearward ejection of the spent mandrel portion.
A further object of this invention is to provide a riveting tool of simple, reliable construction employing fluid pressure mechanism for controlling the relative radial positions of the mandrel pulling jaws at the beginning and end of their operating stroke whereby successive mandrel rivets are cyclically loaded and installed in a rapid manner.
To these ends, and in accordance with a feature of the invention, a jaw case is axially movable in a riveting body and coupled to an inner sleeve operable by fluid pressure, air pressure constantly urging the sleeve in one direction and hydraulic pressure being applicable in opposing direction to cause the jaws in the case to pull and break the mandrel of a mandrel rivet, the arrangement being such that the jaws, initially open to receive the mandrel, are closed for gripping it before tensioning is exerted and opened at the end of the mandrel pulling stroke to permit mandrel ejection and reloading.
BRIEF DESCRIPTION OF THE DRAWING The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment and with reference to the accompanying drawings thereof, in which:
FIG. 1 is a view in side elevation of an automatically fed riveting machine, largely corresponding to that disclosed in the cited Henshaw application, in which the riveting head of this invention may be mounted;
FIG. 2 is an enlarged view, largely in axial section, of the riveting head in rest position, its jaws being shown open and positioned forwardly;
FIG. 3 is a section taken on the line IIIIII of FIG. 2; and
FIG. 4 is a detail view illustrating the releasable operating connection of a pulling jaw shown in FIGS. 2 and 3, as seen when viewed transversely of the head.
DESCRIPTION OF THE PREFERRED EMBODIMENTS It will be understood from reference to the Henshaw appli cation referred to above and with reference to FIG. I herein that automatic transfer mechanism generally designated I0 may be employed to present successive mandrel rivets from a raceway 12 into a position wherein a riveting head 14 may be advanced axially to receive their mandrels individually for setting of the rivets when inserted in a workpiece hole. It will, of course, be appreciated that, when desired, each mandrel rivet may also be initially thrust manually axially into the mandrel head 14 for upsetting as will hereinafter be described. In either case a nosepiece 16 (FIGS. 1, 2) of the tool will abut a preformed flange of the rivet (not shown) to be set when the mandrel is actually retracted.
The head 14 is reciprocable along a guideway 17 (FIG. 1) by means of a double-acting cylinder 18, the arrangement in the illustrative machine being such that in its lowermost position a stem portion of the mandrel of the mandrel rivet to be upset will extend through an end opening 20 of the nosepiece 16, between three cooperative pulling jaws 22 (FIGS. 2 and 3) mounted as will shortly be explained, and into the front end of a mandrel expulsion tube 24 axially extending rearwardly through the head. In addition to the nosepiece 16, the head 14 is coaxially comprised of a partly conical cap 26 threadedly receiving the nosepiece, and a square-sectioned, hollow block portion 28 threadedly secured to the cap 26.
The jaws 22 are respectively slidable axially in inclined equispaced bores 30 formed in a jaw case 32. The axes of the cylindrical bores 30 preferably extend about 12 to the longitudinal axis of the head 14, which axis is coincident with that of the opening 20 and a central bore 34 (FIG. 2) of the jaw case 32. Mandrel gripping surfaces 36 of the jaws 22 may be convex and transversely serrated as indicated in FIG. 3. Radially outer or rearward ends of the jaws 22 are T-shaped as shown in FIG. 4 and releasably connected, as by mortise and tenon arrangement, to the forward end of a tubular jaw-controlling member 38 axially shiftable by power mechanism later described.
For causing the jaws 22, when closed on a mandrel stem, to tension and break it, the stem often having a neck portion for this purpose, the jaw case 32 is threadedly secured in the front end of a tubular pulling sleeve 40 (FIG. 2) slidably disposed within the member 38 and movable axially with the tube 24. The rear end of the pulling sleeve 40 slidably extends through a sealing ring 42 seated in an end cap 44 threaded into the back end of the block 28. The latter is also, for reasons later explained, formed to threadedly receive a coupling 46 of a hose 48 connected to a source of air under pressure. The rear portion of the expulsion tube 24 extends into the mouth of a venturi tube 50 (FIG. 2) and is received in an adapter 52 one end of which is threaded into the rear end of the sleeve 40.
In order to control axial movements of the tubular member 38 and the sleeve 40 relative to the head 14 the block 28 is in effect divided into a rear cylinder 54 and a front cylinder 56 by means of a composite seal 58 one face of which abuts an annular shoulder 60 formed in the block 28. A piston 62 in the cylinder 54 is mounted, preferably with a small degree of freedom for compensating movement, on the sleeve 40 and is held against a flange 64 formed thereon by means of a seal 66 and a retainer ring 68 seated in an annular groove formed on the sleeve 40. The axial position of the ring 68 determines the extent to which the jaws 22 can be separated radially for accommodating different mandrel diameters and ensures that hydraulic pressure is operable on a rear face 69 of the member 38 for a purpose later mentioned.
On the opposite side of the piston 62 from the air coupling 46 an inlet 70 admits hydraulic fluid under pressure via a hose 72 (FIG. 1) connected to a pneumatic intensifier (not shown herein but identified by reference character 168 in the abovecited I-Ienshaw application). The arrangement is such that when a spring-retum valve 73 (FIG. I) in an air exhaust line 75 (designated 174 in the prior Henshaw application) associated with the intensifier is actuated by the downward movement of a setscrew 77 carried by the head 14, which is descending to receive the mandrel to be pulled, hydraulic pressure is thereby admitted into the left-hand chamber of the cylinder 54, as viewed in H6. 2, to force the pulling sleeve 40 rearwardly against the air pressure in the right-hand chamber of the cylinder 54.
Affixed on the jaw control member 38 in the front cylinder 56 by means of a pair of retaining springs 74, 74 is a piston 76 having sliding engagement with a cylindrical lining 78. The latter has its rear end abutting the seal 58 and its front end disposed against the rear face of a composite seal 80, the front face of which contacts the rear end of the cap 26. The lining 78 serves to substantially equate the diameters of the cylinders 54, 56. On the rear side of the piston 76 there is an air exhaust port 82 provided for the cylinder 56, and in front of the piston 76 is an air inlet 84 connected by a hose to the aforementioned exhaust line 75 of the intensifier. Accordingly, when the valve 73 of that exhaust line is closed air under pressure is admitted to the cylinder 56 in front of the piston 76 to open the jaws 22, and when the valve 73 is open the front of the cylinder 56 is opened to exhaust through the inlet 84.
When the jaws 22 break off and release the rearward or spent mandrel portion at the end of a riveting cycle, the mandrel is caused by a small, continuous stream of air admitted to an inlet 86 (FIG. 2) in the adapter 52 to be carried rearwardly through the tube 24 and a connecting air and mandrel exhaust hose 88. This airflow also assists the head 14, during its advance for receiving the next mandrel rivet presented thereto, to hold the mandrel in a fully retained condition between the open jaws.
Operation of the head 14 will now be reviewed as employed in the illustrative machine, it being understood that in the event the head were embodied in a hand-held tool coupled to fluid pressure lines, a manually operable trigger would be used to actuate the valve 73. in the rest or head retracted position shown in FIG. 1 the valve 73 is closed and air pressure behind the piston 62 is holding the inner or pulling sleeve 40 and the jaw case 32 forwardly with the jaws open and the case abutting an inner face of the nosepiece 16. When the head 14 is advanced to enable the jaws 22 and the tube 24 to receive an end of the mandrel rivet inserted in a workpiece, the valve 73 is opened automatically by the screw 77, thereby causing the intensifier to introduce hydraulic fluid into the inlet 70, air being released to atmosphere from the cylinder 56. The hydraulic pressure is effective in front of the piston 62 by action on the rear end face 69 of the jaw-controlling member 38, and hence first causes the latter to move forwardly relative to the sleeve 40. Accordingly the jaws 22 close and grip the mandrel while the case 32 is in its foremost position.
As hydraulic pressure in the cylinder 54 builds up, the air pressure behind the piston 62 is overcome thereby retracting the pulling sleeve 40 and jaw case 32 along with the expulsion tube 24 and the adapter 52 as the mandrel is tensioned. The grip of the jaws 22 may increase if there is slippage of the jaw case 32 with respect to the jaws but their relative disposition is maintained by reason of their T-slot connection to the member 38.
Upon fracture of the mandrel, the valve 73 is automatically reclosed to reverse the flow of hydraulic fluid from the inlet 70 and admit air under line pressure to the cylinder 56 in front of the piston 76. Since the area of the piston 76 subjected to air pressure is considerably greater than the corresponding area 5 of the face 69 of the member 38, the latter relatively retracts on the pulling sleeve 40 before the air pressure behind the piston 62 can overcome the fluid pressure in front of it. Consequently the jaws 22 automatically open to release the spent mandrel stem while the jaw case 32 is in its relatively retracted position. The broken off mandrel portion is thereupon expelled rearwardly through the hose 88 by airflow from the inlet 86. As soon as air pressure rebuilds sufficiently behind the piston 62 the jaws 22 are thereby returned to their open and forward position for receiving another mandrel rivet.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:
1. In a fluid pressure operated head for setting mandrel rivets, a body provided with a mandrel-receiving end for abutting the rivet and fluid pressure mechanism relatively movable axially in the body to tension the mandrel for upsetting the rivet when inserted in a workpiece, said mechanism comprising a jaw case retractable from said body end and having a plurality of guideways disposed at a uniform angle about an axis, mandrel gripping jaws respectively slidable in the guideways, a jaw-controlling member coupled to the jaws to restrain them from displacement relative to one another along the axis, and fluid pressure means for retracting the jaw case to cause the jaws to tension the mandrel, said fluid pressure means being operable on the jaw-controlling member to close the jaws in mandrel gripping relation upon relative movement of the member and the jaw case.
2. A head for setting mandrel rivets, comprising a hollow body having a nosepiece for abutting the rivet of a mandrel rivet and receiving its mandrel stem, said body including in coaxial relative sliding relation a tubular jaw holder and a jawcontrolling member, cooperative mandrel gripping jaws within the nosepiece, slidable in the holder, and coupled at their rear ends to the member, piston means respectively operative in spaced cylinder portions of the body and respectively connected to the jaw holder and the jaw-controlling member, and fluid pressure means for actuating the piston means to cause the jaw holder to retract from the nosepiece after closure of the gripping jaws to seize and tension the mandrel, and, before the jaw holder is allowed to return, to relatively return the jawcontrolling member to cause the retracted jaws to release the mandrel.
3. A rivet setting head as set forth in claim 2 wherein an expulsion tube extends axially in the tubular jaw holder rearwardly from said jaws, and pneumatic means operatively connected to said tube is adapted to expel successive spent mandrel stems rearwardly therefrom, said pneumatic means facilitating retention in the nosepiece of mandrel rivets prior to their being gripped by said jaws.
4. A rivet setting head as set forth in claim 2 wherein the rearward ends of each of said jaws has a T-shaped connection with said jaw-controlling member whereby their relative axial disposition is maintained.