US2989750A - Fastener inserting machines - Google Patents

Description

June 27, 1961 D. B. MCILVIN 2,989,750

FASTENER INSERTING MACHINES Original Filed May 3, 1954 Zwventor:

Jana/d .B. M j/w'n United States Patent 2,989,750 FASTENER INSERTING MACHINES Donald B. McIlvin, Danvers, Mass., assignor to United Shoe Machinery Corporation, Flemington, N.J., a corporation of New Jersey Original application May 3, 1954, Ser. No. 427,021, now Patent No. 2,820,966, dated Jan. 28, 1958. Divided and this application Sept. 24, 1957, Ser. No. 685,936

4 Claims. (Cl. 1-106) This invention relates to fastener inserting and more particularly to a hand-held automatic tool for driving fasteners, the tool being identical with that disclosed in my copending application Serial No. 427,021, filed May 3, 1954 (now Patent No. 2,820,966, granted January 28, 195 8), of which this application is a division. My copending application discloses mechanism for separating and orienting headless fasteners, such as sash pins and the like, which mechanism is adapted for feeding fasteners one at a time to a remotely located portable inserting tool. While the present invention is directed primarily toward a tool having improved means for inserting headless fasteners, it will be appreciated from the following disclosure that many features may be utilized in handling other types of fasteners as well. Therefore, the terms sash pin and fastener are in no way limitations on the use of the several features of the invention.

While there have been automatic devices for inserting fasteners proposed in the past, none of them are suitable for driving sash pins with a single blow. A problem regarding energy requirements is presented in driving sash pins which has in general not been encountered by prior portable fastener inserting devices. Such prior devices have been primarily intended for driving, by a single blow, tacks of a relatively light weight. Tacks are also easier to drive because of their very narrow. pointed construction. Sash pins on the other hand with their thicker bodies and relatively blunt points require substantially more energy to drive particularly when it is necessary to drive them into hard wood such as rock maple. It is, therefore, evident that a hand-held portable device for driving larger fasteners, such as sash pins, cannot be obtained merely by expanding or enlarging the proportions of previous devices for to do so would defeat the feature of portability, unless the air pressure for operating them were increased to an excessively high level which would be not only uneconomical but dangerous.

An object, therefore, of the present invention is to provide an improved fastener inserting device which is particularly adapted for driving large heavy fasteners.

Another object of the present invention is to provide a light weight portable fastenerinserting tool having energy in the form of compressed air sufiicient under adiabatic expansion to drive a fastener by a single blow.

Another object of the present invention is to provide a light Weight portable fastener inserting tool to which fasteners may be fed automatically and which may be fired with a minimum amount of effort on the part of an operator.

In accordance with the various features of this invention there is provided a fastener inserting tool having a two diameter piston to one side of which a fastener driver or shank is attached. Air passages are provided so that in its at rest or cocked position pressurized air (from a normal factory air system, for example) acts against both sides of the piston holding the driver in a retracted position. The tool is provided with a yieldable nosepiece body having a fastener receiving chamber which includes an intersecting passage through which the driver shank may travel. A fastener delivery or entry tube, leading from a supply of fasteners, is connected to the nosepiece body in communication with the fastener receiving chamice her. An adaptor member is provided having intercom necting means for enabling the nosepiece body and the main housing of the tool to be reciprocated relative to each other whereby the driver shank in one position is retracted from the fastener passageway to facilitate the feeding of fasteners and in another position the driver shank is advanced into driving position blocking the entry of further fasteners to the nosepiece body. When the nosepiece body is forced against a work piece, it is displaced relative to the housing, venting to atmosphere the pressurized air acting against the lower or driver contacting surface of the piston and completely sealing off the air passages leading to said lower surface. When the lower surface is thus vented, the piston and driver are driven rapidly in a direction to drive a sash pin or other fastener which had previously been delivered to temporary retaining means within the nosepiece body. The upper end of the piston or the side remote from the driver is provided with a bore which serves as an air accumulator. The air compressed within this accumulator has sufiicient energy to drive the fastener under normal adiabatic expansion without depending upon the flow of additional air to the tool. This feature greatly reduces the necessary size of the tool and permits larger sizes of fasteners to be driven with lower initial air pressure than has heretofore been possible.

The above and other features of the invention including various novel details of construction and combina: tion of parts will now be more particularly described with reference to the accompanying drawings and pointed out in the claims.

In the drawings:

FIG. 1 is a vertical section of a fastener inserting tool embodying the invention;

FIG. 2 is a view similar to FIG. 1 with the various parts shown in fastener driving positions;

FIG. 3 is a section on the line IIIIII of FIG. 2 on a slightly enlarged scale;

FIG. 4 is a section on the line IV-IV of FIG. 1; and

FIG. 5 is a section on the line VV of FIG. 1.

Referring to FIG. 1 the general arrangement of the fastener inserting tool may be seen. It comprises a casing or housing 10 of tubular form which the operator grips when using the tool. A nosepiece 12 is slidably and yieldably mounted relative .to the lower portion of the housing 10 and'has at its lower end a nozzle 14 secured thereto by a snap ring 16. A sleeve 18 having two concentric bores 20 and 22 is provided within'the housing 10. Within this sleeve a piston 24 having two diameters corresponding to the bores 20, 22 is arranged for sliding movement with a driver or shank 26 extending from its lower end or surface. The driver 26 is secured to the piston 24 by a screw 28.

The nosepiece 12, which may also be termed a body or nosepiece body, is provided'with a fastener receiving chamber 30 comprising an opening 32 into which is'inserted a fastener delivery or entry tube 33-, the opposite end of the tube bing connected to a supply of fasteners. An insert 34 is secured within the nosepiece body '12 and 'has a; slot or chamber 36 which is in register with the chamber 30. Jaws comprising a spring-fingered quill 38 are secured between the insert 34 and the nozzle 14 and constitutes a fastener guiding member. This construc tion permits fasteners to be delivered through the entry tube 33 through the slot 36 into the fastener receiving chamber 30 under pneumatic pressure, and into the fastener guiding member or jaws 38 where they are temper arily positioned one at a time preparatory to being driven; A bore 40 within the insert 34 in the body or nosepiece body 12 is aligned wit hthe fastener guiding member 38 and provides a passageway for the driver or shank 2 6;

At the end of the housing 10 adjacent the nosepiece body 12 is aligned with the fastener guiding member 38 in the housing 10. The nosepiece body 12 is arranged for reciprocating movement relative to the housing 10 by the following interconnecting means. A sleeve 43 extends from the nosepiece body 12 and surrounds the housing 10. A screw 46 threaded into the adaptor 42 with its head riding in a slot 48 in the sleeve portion 43 of the nosepiece body 12 limits the downward movement of the nosepiece body 12 and nozzle 14 relatively to the housing 10. A compression spring 44 yieldably urges the nosepiece body 12 away from the housing 10 of the tool, the spring 44 acting between a shoulder formed on the insert 34 and a recess '45 in the adaptor. The slot 48 is of sufficient length to allow the nosepiece body 12 to be moved against the action of the spring 44 until the insert 34 abuts the adaptor 42. The adaptor 42 is provided with a bore 50 through which the driver or shank 26 passes; however, the clearance is such that a substantially airtight seal is maintained.

The sleeve 18 is maintained in longitudinal position within the housing 10 by the adaptor 42 and by a plug 52 secured by a snap ring 54 to the upper end of the housing 10. A signal line 56 connected to the fastener feeding mechanism and an air supply line 58 are secured to the plug 52 by suitable fittings 60, 62. The air supply line 58 is at all times pressurized and communicates through an offset passageway 64 in the plug 52 with the upper surface of the piston 24. It should be noted that the piston 24 has a bore 66 which is adapted to serve as an air accumulator extending from its upper surface. Pressurized air is also maintained in communication with the lower surface of the piston 24 when the parts are in the positions shown in FIG. 1 by the structure now to be described. The plug 52 is provided with a number of radial grooves 68 which communicate with holes 70 formed in the sleeve 18 which in turn communicate with slots 72 (FIG. which extend downwardly along the sleeve 18 terminating at points in register with holes 74 formed in the housing 10. The holes 74 are in communication with further holes 76, 78 formed in the housing and the sleeve 18, respectively (FIG. 3), through an elongated annular recess 80 formed in the sleeve portion 43 of the nosepiece body 12.

With the nosepiece body in its at rest position (FIG. 1) the piston 24 is normally maintained in its upper position due to the fact that the lower surface of the piston has a larger area than the upper surface and the pressures acting on both surfaces are equal. When the tool is pressed against a work piece W, the nosepiece body 12 and the housing 10 are moved relatively toward each other against the force of the spring 44 until the parts assume the positions shown in FIG. 2. The pressurized air acting on the lower surface of the piston 24 is immediately vented to atmosphere through the holes 76, 78 and a corresponding series of holes 82 formed in the sleeve portion 43 of the nosepiece body 12. The piston moves with explosive force to drive a fastener F which has previously been delivered to the fastener guiding member or jaws 38. Movement of the piston 24 and the driver or shank 26 is limited by engagement of a shock absorbing pad 84 with the adaptor 42. Since it is often desirable to drive fasteners, such as sash pins, a substantial distance below the surface of the work piece as shown in FIG. 2, the depth of drive is dependent upon the selection of the length of the driver or shank 26. While the air supply from the line 58 at all times remains in communication with the upper surface of the piston 24, the accumulator formed by the bore 66 is of sufiicient size so that the air compressed therein has sufiicient energy to drive the fastener F by adiabatic expansion without depending upon the flow of additional pressurized air through the line 58. Thus, the energy for driving the piston is not dependent upon the flow of air through openings which would act as restrictive orifices. This feature, in combination with the large number of venting holes 76, 78 and 82, combines to provide a greater amount of energy in relation to the size of the inserting tool than has heretofore been obtained by using nominal air pressures in the range of 60-400 p.s.i. which are available in most air systems. A further feature which increases the amount of energy available is provided by the construction of the nosepiece body 12. It will be noted that when the nosepiece body is in the FIG. 2 position, the holes 76, 78 and 82 have only one function, namely, to vent the pressurized air from the outer bore of the sleeve 18 and in such position the pressurized air from the slots 72 is confined within the recess 80.

When the piston 24 is in its FIG. 2 position, also known as the first position, the signal line 56 is pressurized for the purpose of actuating the remotely located fastener feeding device to supply a fastener to the fastener guiding member or jaws 38 by way of the entry tube 33. The signal line 56 becomes pressurized by air passing through a passageway comprising a hole 86 formed in the sleeve 18, a groove 88 also formed in said sleeve which continum toward the plug 52, and an offset passageway 90 in said plug which leads to the signal line 56. It will be noted that the hole 86 is so located that when the piston 24 is in its lowermost position the signal line is connected to the pressurized chamber above the piston 24, thus pressurizing the signal line 56.

In order to prevent air leakages there are provided within the inserting tool certain annular rings of circular cross section which are fitted in appropriate recesses. These rings are preferably of polychloroprene. A ring 91 prevents leakage of air through the sliding connection between the sleeve portion 43 of the nosepiece body 12 and the housing 10. A ring 93 serves as a seal between the upper and lower surfaces of the piston 24. A ring 95 prevents leakage of air from the radial grooves 68 into the groove 88 leading to the signal line 56. A ring 97 forms an airtight seal between the plug 52 and the housing 10. The ring 93 is of particular importance in that it greatly reduces the manufacturing tolerances which must be maintained in machining the bores 20, 22 and the corresponding diameters of the piston 24.

When the tool is removed from the work piece W, the nosepiece body 12 and the housing 10 move relatively away from each other, the parts assuming the positions shown in FIG. 1, hereinafter known as the second position, under the action of the spring 44 whereupon the lower surface of the piston 24 again is acted upon by pressurized air causing the piston to assume its upper or second position. In the first or FIG. 2 position, it will be noted that the driver shank 26 restricts the passage of fasteners from the entry tube 33 to the jaws 38 should a fastener reach the nosepiece body 12 before the driver shank has been retracted. The signal line 56 remains pressurized until the piston 24 has substantially reached its upper position after which it is depressurized by being vented to atmosphere when an annular recess 92 formed on the piston 24 places it in communication with a hole 94 formed in the sleeve 18 and the housing 10. The hole 94 serves a further function of eliminating, when possible, drag which suction or vacuum might create as the piston is being driven.

Referring now to the operation of the tool, it is shown in its at rest position in FIG. 1 with pressurized air from the supply line 58 acting against both the upper and lower surfaces of the piston 24. Due to the fact that the lower surface, i.e. the surface nearest to the nosepiece body 12, has a larger area than the upper surface, the piston 24 is maintained in the upper position with the driver or shank 26 retracted from the fastener receiving chamber 30. In the at rest position the signal line 56 is depressurized. To operate the tool an operator may grasp it by the housing 10 forcing the nozzle 14 against a work piece W compressing the spring 44 thereby causing the nosepiece body 12 to assume the position shown in FIG. 2 relative to the housing 10. In this position air pressure acting against the lower surface of the piston 24 is vented to atmosphere through the holes 78, 76 and 82. The fact that the recess 80 in the sleeve portion 43 of the nosepiece body 12 is no longer in communication with the holes 76 and 78, the supply of air pressure to the lower surface is cut off. Immediately, the pressurized air accumulated in the bore or accumulator 66 forces the piston 24 and the driver or shank 26 downwardly in an explosive manner to drive a fastener F temporarily retained in the jaws 38 into the work piece W. This driving or FIG. 2 position is also termed the first po sition. The energy of the compressed air within the accumulator 66 is suflicient alone under adiabatic expansion to drive the fastener F without depending upon further flow of air through the line 58. When the piston 24 is in its downmost or first position, the signal line 56 becomes pressurized. Pressurization of the signal line signals the remotely located fastener feeding mechanism to convey the next fastener through the entry tube 33.

When the tool is removed from the work piece, the nosepiece body 12 again assumes the position shown in FIG. 1, which may also be termed the second position, by the force of the spring 44 and the piston 24 moves upwardly as pressurized air is admitted to the lower surface of said piston. The signal line 56 is again depressurized.

It will be noted in some instances that the fastener F will arrive at the tool while the driver or shank 26 blocks entrance to the jaws 38. However, there is enough air pressure remaining in the entry tube 33 after the driver is withdrawn, especially in view of the fact that the signal line 56 remains pressurized during a substantial portion of the upward movement of the piston 24, to cause the fastener to be conveyed to the jaws 38 when the driver or shank 26 is withdrawn therefrom.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1'. A fastener inserting tool having, in combination, a nosepiece, a housing, the nosepiece and the housing being mounted for relative sliding movement when the tool is forced against a work piece, means within the nosepiece for positioning a fastener to be driven, a piston in said housing having two diameters the lower of which is the larger, a plurality of radially spaced passageways in the housing adjacent the nosepiece at all times in communication with the larger side of the piston, normally operative means for introducing equal air pressure to both sides of said piston including means for directing air to said passageways, a driver extending from the larger side of said piston toward said nosepiece for driving a fastener held in said positioning means, means for venting to atmosphere through the said radially spaced passageways adjacent the nosepiece the pressurized air acting on the larger diameter side of said piston upon the nosepiece being forced against a work piece, and means for completely sealing and thereby rendering inoperative the means for directing pressurized air to said passageways when the nosepiece is thus forced.

2. A fastener inserting tool having, in combination, a nosepiece, a housing, the nosepiece and the housing being mounted for relative sliding movement when the tool is forced against a Work piece, means within the nosepiece for positioning a fastener to be driven, a piston in said housing having two diameters the lower of which is the larger, means for introducing equal air pressure to both sides of said piston, a bore formed in the upper side of said piston which serves as an accumulator and is of sufficient size so that the energy of air compressed therein is sufiicient under adiabatic expansion to drive a fastener, a driver extending from the larger diameter side of said piston for driving a fastener held in said positioning means, means for venting to atmosphere the pressurized air acting on the larger diameter side of said piston upon forcing the nosepiece against a work piece, and means for completely sealing the means for introducing pressurized air to the larger diameter side of said piston when said nosepiece is thus forced.

3. A head for attachment to a fastener inserting tool of the kind which includes a housing from which projects the driving end of a driver shank, comprising a nosepiece body having a fastener receiving chamber which includes a passage for the reception through one end of the driving end of the shank of the inserting tool, an entry tube on the nosepiece body having an exit end which opens into the chamber and a second end for connection to a supply of fasteners, an adaptor member for firm alttachment to the inserting tool, interconnecting means between the nosepiece body and the adaptor member ena-bling reciprocation of the adaptor member and thus of the attached inserting tool relative to the nosepiece body between a first position where the shank is advanced relative to the body and a second position where the shank is retracted, biasing means normally urging to the second position the adaptor member relative to the nosepiece body, and a fastener guiding member on the body at the other end of the aforesaid passage to receive a fastener admitted into said chamber from the entry tube and to hold said fastener in driving position and in alignment with the driver shank, and signalling means responsive to the relative movement of the adaptor member and the body from the second position to the first position to initiate the delivery of subsequent fasteners.

4. A head for attachment to a fastener driving tool of the kind which includes a housing from which projects the driving end of a shank, comprising a body having a fastener receiving chamber which includes a passage for the reception through one end of the driving end of the shank of the driving tool, an entry tube on the body and having an exit end which opens into the chamber and another end for connection to a supply of fasteners, an adaptor member for firm attachment to the driving tool, interconnecting means between the body and the adaptor member enabling reciprocation of the adaptor member and thus of the attached driving tool relative to the body between a first position where the shank is advanced relative to the body and a second position where the shank is retracted, biasing means normally urging to the second position the adaptor member relative to the body, a fastener guiding member on the body at the other end of the aforesaid passage to receive fasteners admitted into the chamber from the entry tube and to hold them one at a time in driving position and in alignment with the shank, and control means responsive to the relative movement of the adaptor member and the body from the second position to the first position.

References Cited in the file of this patent UNITED STATES PATENTS 1,618,367 Dick Feb. 22, 1927 1,978,118 Stevens Oct. 23, 1934 2,482,993 Walker Sept. 27, 1949 2,732,554 Knott Jan. 31, 1956 2,807,021 Chellis Sept. 24, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2 989 75O June 27 1961 Donald B. Mcllvin It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 2,, strike out "aligned with the fastener guiding member 38" and insert instead an adaptor 42 in the form of a cap threaded -u Signed and, sealed this. 24th day of April 1962.

(SEAL) Attest:

ESTON G7. JOHNSON AVID L- LADD Attesting Officer Commissioner of Patents

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