US2787923A - Portable tool for applying spring nut fasteners - Google Patents

Description

April 9, 1957 P. c. wooLlvER 2,787,923

PORTABLE TOOL FOR APPLYING SPRING NUT FASTENERS INVENTOR il l 5522 A @JM ATTORNEY April 9, 1957 P. c. wooLlvER 2,787,923

- PORTABLE TOOL FOR APPLYING SPRING NUT FASTENERS Filed May ll, 1953 2 Sheets-Sheet 2v INVENTOR ATTORNEY United States Patent PORTABLE TOOL FOR APPLYING SPRING NUT FASTENERS Phillip C. Wooliver, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 11, 1953, Serial No. 354,327

Claims. (Cl. 81-3) This invention relates to tools for applying spring-nut fasteners and the like and particularly to portable tools which may readily be operated with one hand.

The spring-nut fastener is well known in the art and widely utilized for securing emblems, escutcheon plates and decorative panels to a supporting wall. In the typical installation a suitable escutcheon plate is provided with one or more projections or integral studs on its rear surface which are adapted to project through corresponding apertures formed in a supporting wall. The springnut fasteners are thereafter forced over the free ends of studs into firm engagement with the rear surface of the wall to retain the plate in position. ln the past, the use of spring-nut fasteners in certain locations has occasioned considerable diiiiculty, as for instance when the construe tion or formation of the supporting body prevented application of direct pressure to the spring-nut or required diflicult manual manipulation. It is therefore desirable that means be provided for seating the spring-nut in severely limited or blind locations and regardless of the angle of access to the studs.

One object of the invention is to provide a compact and highly portable thrust applying tool which is especially adapted for applying spring-nut fasteners in relatively inaccessible locations.

Another object is to provide a tool of the type described which is self-actuating along a xed stud, regardless of the direction of access to the stud.

A still further object is to provide a tool of the type described having pressure responsive means adapted to initially grip a fixed member and subsequently displace ltahe entire tool forwardly with reference to the xed mem- Yet another object is to provide a tool of the type described having interchangeable nose portions of various configurations which permit access to severely restricted locations.

A still further object is to provide a tool of the type described which is simple in construction, ecient in operation and convenient to manipulate.

These and other objects and advantages of the invention will become more fully apparent as reference is had to the accompanying drawings wherein:

Fig. l is a sectional side elevational View showing the construction and arrangement of the parts when the tool is in the relaxed position.

Fig. la is an enlarged fragmentary sectional view of a portion of the tool shown in Fig. 1.

Fig. 2 is a side elevational view, similar to Fig. l, with parts broken away and partly in section, showing the relationship of the parts when the tool is in the operative position.

Fig. 3 is a front elevational view, partly in section, of a portion of the tool taken substantially along the lines 3-3 of Fig. l.

Fig. 4 is a plan view, partly in section, of a portion of the tool taken substantially along the lines 4 4 of Fig. l, and Fig. 5 is a plan view, partly in section, showing a modified form of jaw holder for the tool.

Referring now to the drawings and particularly Fig. 1 there is illustrated a pneumatically operated hand tool wherein the reference numeral 2 indicates a cylinder body having an integral downwardly depending hand grip portion 4. Cylinder body 2 is formed with a relatively large diameter longitudinally extending bore 6 which is adapted to receive a press-tted sleeve cylinder 8 having a smooth internal wall l0. At its forward end 3, cylinder body 2 is provided with concentrically disposed stepped annular bores 12 and 14 in which is press-fitted a flanged bushing 16. Bushing 16 is provided with a central reamed bore 18 which extends therethrough in axial alignment with the cylinder S. Substantially midway of bushing 16 there is provided an annular groove 20 which is adapted to receive a circular compression gasket 22. Slidably disposed within the cylinder 8 is a piston 24. Piston 24 comprises a relatively long annular midportion 26 having an integral annular rib 28 formed substantially midway thereof and adapted for slidable engagement with the wall l0 of sleeve 8. Annular rib 28 is formed with a circumferential groove 30 which carries a circular 0- ring 32 which is normally round in cross section. When installed, Oring 32 is placed in compression against the periphery of cylinder wall 10 to assure a uid tight seal therebetween. To axially position piston 24 in cylinder 8, a relatively heavy gauge coil spring 34 is disposed in the rear portion 36 of the cylinder 8. After insertion of spring 34, a cylinder housing cover 38 having a centrally disposed bleeder hole 4th is disposed over the rear surface of housing 2. Cover 38 closes the open rear end of cylinder 8 except for the aperture formed by bleeder hole 4i) and is tightly secured in position by a plurality of radially arranged machine screws 42 which threadably engage threaded apertures 44 formed in the periphery of cylinder housing 2. After housing cover 38 is secured in position, coil spring 34 is compressed between the inner surface 46 of the housing cover 38 and the rear surface 48 of annular' rib 28 formed on piston 24. It will therefore be seen that piston 24 is normally spring urged forwardly into abutting relation with bushing 16, as shown in Fig. l.

To render the piston 24 responsive to pneumatic pressure, hand grip portion 4 is provided with a generally vertical bored inlet passage 5t) extending from the base 51 of the grip portion upwardly into a valve chamber 54 formed substantially midway thereof. A compressed air supply, not shown, is delivered to the gun by a hose 52 which is secured to the base 51 by a threaded coupling 53 communicating with passage S0. Formed at substantially right angles to passage Sti and extending through grip portion 4 is a second bore 56. Press fitted into the forward portion of bore 56 is a cylindrical valve body 58 of stepped external cross section. Interiorly thereof, valve body 58 is provided with stepped annular bores 6d and 62. Annular bore 6i) is formed with a slot 61 providing communication between valve chamber 54 and a vertically extending passage 66 which in turn communicates with the forward portion 68 of cylinder 8. At the rear of hand grip portion 4, bore 56 is provided with internal threads 7i) which threadably receive a thread cap member 72. to close one end of the bore. Prior to assembly of cap 72, a stem valve 74 is endwise inserted through bore 56 and Slidably received in the reduced bore 62 of valve body 5s. At its rear end, stem valve 74 is provided with a shoulder portion 76 forming a seat for a gasket '78. A disc type washer 80, disposed over the reduced end portion 82 of stem valve 7 4 in engagement with gasket 78, is secured in position by peening over the end 82. Near its upper front surface, hand grip portion 4 has formed thereon an integral boss 84 in which is journalled a transversely extending stud 86. Stud 86 provides pivotal support for trigger member 88 lwhich extends downwardly therefrom to engage the rounded outwardly extending end of stem valve 74. It will be seen that upon rearward swinging movement of trigger 88, stem valve 74 will be axially displaced rearwardly, permitting compressed air to pass from valve chamber 54, into bore 60, through slot 61 and passage 66 into the forward portion 68 of Cylinder 8, thereby forcing piston 24 rearwardly against the compression of spring 34. Upon release of trigger 88, stem valve 74 moves axially forward until gasket 78 seals the open end of bore 60 against passage of air from inlet passage 50. When stem valve 74 is in position to close bore 60, a groove 92 formed in the stepped annular midportion 93 of the valve is brought into alignment with a bleeder hole 94 providing communication between passage 66 and avertically extending exhaust passage 96, thereby permitting the compressed air from the forward portion 68 of cylinder 8 to pass outwardly into the atmosphere. lt will be obvious that compression spring 34 will tend to expand to its normal position and force piston 24 forwardly to exhaust the air in forward portion 68 of cylinder 8 whenever the annular groove 92 of stem valve 24 is in alignment with bleeder hole 94 and the intake passage 60 is closed.

In order to utilize the trigger control reciprocating ,action of the piston 24 in accordance with the present invention, the outer forward portion 95 of cylinder body 2 is provided with a threaded pilot 97 which is adapted to threadably receive a cylindrical nose portion 98 having a concentric large diameter inner bore 181i. At its forward end 99, nose portion 98 is closed and provided with a relatively small central aperture 102 communicating with the bore 100. At its rear end, nose portion 98 is formed with an outwardly extending hexagonal ange 104 to facilitate rapid engagement and disengagement with threaded pilot 97. Prior to assembly of nose portion 98, a piston rod 106 having a threaded end 107, is inserted through the bore 18 of bushing 16 and threadedly secured in a threaded bore 108 which extends axially through the center of piston 24. A set screw 110 is threadedly inserted in the rear of threaded bore 108 and is provided with a cross slot 112 permitting longitudinal adjustment thereof to locate piston rod 166 axially of piston 24. Forwardly of piston 24, piston rod 106 is provided with an enlarged shaft portion 114 which is machined toslidably t the bore 18 of bushing 16 and compress the gasket 22 circumferentially disposed therein. It will be apparent that relatively close tolerance between the bore 18 and shaft portion 114 is necessary in order to assure a uid tight seal therebetween and prevent escape of compressed air ldirected into the forward cylinder portion 68. At its forward end, piston rod 106 is formed with a relatively long enlarged circular head 116 having a vertically directed relatively narrow slot 11S milled therein. with a transversely directed aperture 120. Aperture 120 carries a press tted pivot pin 122 which is adapted to support a circular camming roller 124. Roller 124 is freely rotatable on pin 122 and is constrained against axial movement thereon by the opposed walls of the slot 118. Slidably disposed in bore 100 of nose 98 in telescoping relation with enlarged head 116 is a cup-shaped jaw holder 128. Jaw holder 123 is provided with a relatively narrow slot similar to slot 118 of head 116 and disposed in alignment therewith. A pair of pivot shafts 132 and 134 are journalled in transversely directed bores 136 and 138 formed in the forward portion 1413 of jaw holder 128. Shafts 132 and 134 are spaced equidistant above and below the center line of jaw holder 128 and pivotally support a pair of jaws 142 and 144, which are constrained against sidewise movement by the walls of slots 118 and 130. On their respective inner rear edges, jaws 142 and 144 are formed with opposed rearwardly converging contoured surfaces 146 and 148 which are adapted for slidable engagement with camming roller Midway of the slot 118, head 116 is provided 124. On their respective forward inner edges, jaws 142 and 144 are provided with opposed serrated surfaces 150 and 152 which are adapted for non-slip gripping engagement with a stud 154 formed on an escutcheon plate 156. Jaw holder 128 and jaws 142 and 144 are normally retained in the forward position shown in Fig. 1 by a heavy coil spring 158 which is disposed in tension between the pilot 97 and the rear edge 160 of jaw holder 128. When jaw holder 128 and piston rod 106 are in full forward position the camming roller 124 occupies a position between the opposed contoured surfaces 146 and 148 per mitting the jaws 142 and 144 to swing open to the position shown in Fig. 1 and permit the stud 154 to extend through aperture 102 into the opening between the serrated surfaces and 152. A generally U-shaped spring member 162 is secured at the base of slot 118 by a machine screw 164 and is adapted to engage the outer in clined rear edge portions 166 and 168 of jaws 142 and 144 to urge the jaws to the normally open position.

In order to more fully understand the invention, a description of the sequency of operation will be given. Assume that a suitable escutcheon plate 156 has been placed in position on a supporting wall 172 with the integral stud portion 154 extending through a suitable aperture in the wall. A spring clip 174 is then dis posed over the stud 154 and manually forced a suitable distance toward the base of the Stud. The nose 98 of the tool is then moved endwise over the stud to a position permitting the end portion 176 of the stud to extend through the aperture 102 for engagement by the serrated portions 158 and 152 of jaws 142 and 144. Following placement of the tool, the trigger 88 is depressed to displace stem valve 74 and admit compressed air through valve body 58 into the forward portion 68 of cylinder 8 to urge the piston 24 and piston rod 106 rearwardly against coil spring 34. Upon initial rearward movement of piston 186, the camming roller 124 carried therewith moves rearwardly to separate the converging contoured portions 146 and 148 of the jaws causing the forward serrated portions 150 and 152 to grippingly en gage stud 154. As the piston 24 and piston rod 106 continue to move rearwardly the body of stud 154 prevents further converging of the serrated portions of the jaws, therefore further rearward movement of camming roller 124 imparts rearward slidable movement to jaw holder 128 against the compression of spring 158. While the jaw holder 128 moves rearwardly relative to the nose 98, it is now fixed relative to the stud 154, therefore, the nose is moved forwardly along the stud 154 forcing spring spring clip 174 toward the base of stud 154, thereby seating the spring clip in firm engagement against the inner wail surface 178. In order to provide a predetermined degree of resiliency after final seating of the spring clip 174, the forward closed portion 99 of the nose 98 is pro vided with a milled recess 18) which surrounds the aperture 102. It will be apparent that the depth of the recess 180 will determine the iinal angle of inclination of each of the gripping portions 182 and 184 of the spring clip 174, as shown in Fig. 2. Upon completion of the seating operation, the trigger 88 is released and permits the stem valve '74 to return to the position shown in Fig. l, allowing the compressed air in forward portion 68 of the cylinder 8 to pass outwardly through exhaust port 96. As the air leaves the forward portion 68, compression spring 38 moves the piston 24 and piston rod 186 forwardly. Simultaneously, spring 158 moves jaw holder 128 forwardly, thereby repositioning the jaws 142 and 144 in the relaxed forward position shown in Fig. l for repetition of the operation.

in Fig. 5 there is shown a modication of the invention wherein the nose barrel 188 is provided with a forwardly extending portion 198 of reduced diameter. This modiiication is especially suitable for applying spring clips where access must be had to a stud through circular apertures of insuicient diameter to permit insertion of the normal nose barrel. Since such applications also interfere with the initial manual placement of the spring clip on the stud, the tip 192 of the reduced portion 190 is provided with suitable permanent magnet elements 194 which magnetically retain the clip in position on the nose of the tool. With this modification the clip may be placed on the tip of the tool for insertion through a restricted circular aperture and disposed over the stud, thereby permitting installations which would otherwise present considerable diiiiculty. It will, of course, be apparent that similar magnet elements may also be embedded in the end of nose barrels of blunt configuration.Y

From the foregoing it will be seen that a novel and highly efiicient tool has been provided which permits rapid placement and seating of spring clip fasteners and assures unvarying duplication of tensioning of the fasteners. In addition, the mode of operation of the tool permits placement and seating of clips in locations heretofore virtually inaccessible.

While several embodiments of the invention have been shown and described, it will be apparent that other changes and modifications may be made therein. It is therefore to be understood that it is not intended to limit the invention to the embodiments shown but only by the scope of the claims which follow.

I claim:

1. A tool for seating a spring fastener on a cooperating projection, comprising a main body portion having a cored hand grip formed thereon, a generally cup-shaped nose portion secured on said body portion, means forming an aperture in said nose portion, said aperture being adapted for surrounding disposition about said projection, a recessed fastener engaging portion formed on said nose portion adjacent said aperture, a pair of jaws pivotally mounted in said nose portion, a pressure responsive member slidably disposed in said tool, a jaw spreading cam on said member, said cam being initially movable relative to said projection to pivotally urge said jaws into gripping engagement therewith, said jaws, after initial spreading movement, being adapted to prevent further movement of said cam relative to said projection whereby said nose portion is bodily forwardly displaced along said projection to urge said fastener axially thereof into seated position.

2. A tool for seating spring fasteners on cooperating projections, comprising a generally hollow body portion having an integral hand grip formed thereon, a substantially cup-shaped nose portion threadably secured on said body portion, means formed on said nose portion permitting insertion of said cooperating projection, a relieved fastener engaging portion formed adjacent said last mentioned means, a jaw holder slidably disposed in said nose portion, a pair of jaws pivotally secured in said jaw holder, cani follower means on said jaws, a pressure responsive member slidably disposed in said body portion, a rod secured to said pressure responsive member and movable therewith cam means formed on said rod and engaging said cam follower means, said cam means being adapted upon initial movement thereof to spread said cam follower means and pivotally urge said jaws into gripping engagement with said projection, said jaws in gripping position preventing further spreading of said cam follower means thereby arresting movement of said rod relative to said jaws, whereby said nose portion is slidably displaced axially relative to said rod to seat and tension said fastener.

3. A tool for seating spring fasteners on cooperating projections, comprising a generally hollow body portion having an integral hand grip formed thereon, an interchangeable substantially cup-shaped nose portion threadably secured on said body portion, means formed on said nose portion permitting insertion of said cooperating projection, a relieved fastener engaging portion formed adjacent said last mentioned means, a jaw holder slidably disposed in said nose portion, a pair of jaws pivotally secured in said jaw holder, a pressure responsive member slidably disposed in said body portion, a rod secured to said pressure responsive member and movable therewith, a cam on said rod, said cam being adapted upon initial movement thereof to pivotally urge said jaws into gripping engagement with said projection, said jaws in gripping position being adapted to prevent relative movement thereafter between said rod and said jaws, whereby said nose portion is slidably displaced axially relative to said rod to seat and tension said fastener.

4. A tool for seating spring fasteners on cooperating projections comprising a main body portion having a substantially c-losed cylinder formed therein, hand grip means formed integrally on said body portion, compressed fluid passages formed in said hand grip, and communicating with said cylinder means for controlling the iiow of said iiuid in and-out of said cylinder, a generally cupshaped nose portion threadably secured on said body portion in axial alignment with said cylinder, means formed on said nose portion permitting insertion of said cooperating projection, a jaw holder slidably disposed in said nose portion and yieldably urged to the forward portion thereof, a pair of jaws pivotally secured in said holder, and normally urged to a relaxed position, a iiuid responsive piston slidably disposed in said cylinder, a piston rod extending between said nose and said cylinder, and engaging said piston, said rod having means formed thereon for contracting said jaws into gripping engagement with said projection in response to initial movement of said piston, the outer edges of said jaws engaging said jaw holder and operative to render said piston stationary relative to said jaws after said initial movement thereof whereby fluid pressure on said piston compressibly urges said nose portion forward relative to said piston, and yieldable means for returning said piston and jaw holder to the forward position when said compressed iiuid is released.

5. A tool for seating spring fasteners on cooperating projections comprising an annular cylinder body having an integral hand grip for-med thereon, a substantially cup-shaped nose portion threadably secured at one end of said cylinder body in laxial alignment therewith, means yformed on said nose portion permitting insertion of said cooperating projection, a relieved fastener abutting portion formed adjacent said last mentioned means, a jaw holder slidably disposed in said nose portion, a pair of jaws pivotallyy secured in said jaw holder, each of said jaws having inner ends and outer ends, a uid pressure responsive member disposed in said cylinder and adapted for substantial relative slidable movement therein, means mounted on said hand grip for controlling said iiuid pressure, and a rod secured to said pressure responsive member and movable therewith, means on said rod engaging said inner ends of said jaws and adapted upon initial movement thereof to separate said inner ends and close said outer ends of said jaws for gripping engagement with said projections without imparting movement to said jaw carrier, said inner ends of said jaws being adapted to prevent relative movement thereafter between said rod and said jaws, whereby said body and nose portion is slidably displaced axially relative to said jaws and jaw carrier to seat and tension said fastener.

References Cited in the tile of this patent UNITED STATES PATENTS 110,789 Robertson Ian. 3, 1871 1,898,376 McCulloch et al Feb. 21, 1933 2,177,232 Tinnerman Oct. 24, 1939 2,301,889 Lear Nov. 10, 1942 2,341,063 Tinnerman Feb. 8, 1944 2,372,973 Morgan Apr. 3, 1945 2,575,320 Tinnerman et al Nov. 13, 1951 FOREIGN PATENTS 266,058 Germany Oct. 17, 1913

Images