US 3669087 A
Description (OCR text may contain errors)
United States Patent Hamrick et al.
[ June 13, 1972  LINE THROWING GUN  Inventors: James C. Hamrick; Howard G. Ruddick,
both of Charlotte, NC.
 Assignee: Jet Line Products, Inc., Matthews, NC.
 Filed: Aug. 17, 1970  Appl. No.: 64,246
 US. Cl ..l24/l l, 254/l34.4, 226/97, 124/30 R  lnt.Cl ..F4lf7/00  FieldofSearch ..l24/ll,3l;254/134.4
 References Cited UNITED STATES PATENTS 1,827,239 10/1931 Kelley ..254/l34.4
l-lamrick 124/1 1 UX 3,382,859 5/1968 Myers ..124/ll Primary ExaminerRichard C. Pinkham Assistant Examiner-R. T. Stoufi'er Attorney-Patron, Bell, Seltzer, Park 84 Gibson [5 7] ABSTRACT A gas operated line throwing gun for casting a line package across a relatively non-accessible area such that the trailing line endmay be used to pull a heavier electrical line through i the-area. The gun includes a lightweight barrel defining a continuous tubular passageway, and one or more escapement portsare provided which extend radially through the barrel wall for releasing the gas pressure in the event the barrel is obstructed when fired, to thereby preclude bursting of the same.
11 Claims, 6 Drawing Figures LINE TI-IRQWING GUN The present invention relates to an apparatus for casting a line package through a relatively non-accessible area, such as through an underfloor duct or over an expanse of a suspended ceiling.
In the installation of electrical wires or cables, it is often desired to position the cables through or across areas which are not readily accessible. In such cases, it has been proposed to utilize a line throwing gun which propels a line package through the area while leaving a trailing lightweight line end. A strong rope may then be tied to the line end and pulled through the area, which in turn may be used to pull the electrical wires or cables through the area.
Known guns of the above type are powered by compressed air or gas, and include a tubular barrel constructed from heavy wall steel pipe which provides sufficient strength to prevent bursting in the event that the barrel is obstructed when fired. The barrel further includes a breach opening through the wall thereof to admit the line package, and a slidable plastic cover overlies the barrel to selectively open or close the breach opening. A gun of this general design is disclosed in the U. S. Pat. to Myers, No. 3,382,859.
The guns of the above design have been found to possess several inherent disadvantages which have precluded their generalacceptance in the industry. For example, the fact that the barrel is made from steel makes the gun unduly heavy and cumbersome to use. In addition, an accidental firing of the gun while the breach opening is uncovered could discharge the line package through the opening with the attendant opportunity for serious injury to the operator.
Accordingly, it is an object of the present invention to provide a lightweight line throwing gun which can be easily handied and utilized.
It is an additional object of this invention to provide a line throwing gun which is safe in its operation in that the line package can only be ejected from the discharge end of the gun, and further wherein express provision is made to preclude explosive bursting of the gun barrel in the event the end is obstructed when fired.
These and other objects and advantages of the present invention are achieved in the embodiment illustrated herein by the provision of a gun which comprises a lightweight barrel having a cylindrical wall which defines a continuous tubular inner passageway. One end of the barrel mounts a coupling for securing the sameto a sourceof compressed gas, and the other end may mount a similar coupling for selectively connecting an arcuately curved barrel extension. One or more escapement ports, which may take the form of hollow dowel pins, extend radially through the barrel wall and are adapted to vent the gas from the barrel in the event that it is obstructed whenfired.
Some of the objects and advantages of the invention having been stated, other will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is a perspective view, partly sectioned, illustrating the manner in which the line throwing gun of the present invention may be used to cast a line package through an underfioor duct;
FIG. 2 is a side elevational view of the line throwing gun of the present invention;
FIG. 3 is an enlarged fragmentary view illustrating the means for coupling the gun to a source of compressed gas;
FIG. 4 is an enlarged sectional view of the coupling means shown in FIG. 3, and illustrating the same as being interconnected; I
FIG. 5 is an enlarged fragmentary sectional view showing the coupling means at the discharge end of the gun for connecting the same to the barrel extension; and
FIG. 6 is a horizontal sectional view taken substantially along the line 66 of FIG. 5.
Referring more specifically to the drawings, the line throwing gun of the present invention is illustrated generally at 10, and in FIG. 1 is illustrated casting a line package through a typical underfloor duct 11. The gun generally includes a source of compressed air or gas 12, a barrel 14, and an arcuately curved barrel extension 16; The source of compressed gas 12 is of conventional, known construction and includes the storage bottle 18 and a hand operated valve 20 for selectively releasing a quantity or burst of compressed gas therefrom. The discharge end of the valve 20 is connected by a quick disconnect coupling 22 of conventional design to the flexible hose 24, which in turn is releasably coupled to a first or loading end of the barrel 14 by an arrangement which includes a first sleeve 26 having a tubular male extension 28 secured to the barrel l4 and a second sleeve 30 having a tubular female extension 32 secured to the end of the hose 24. The male extension 28 includes an annular groove 34, and the female extension 32 includes a radially extending threaded member such that when the male member is received in the female member, the threaded member 36.may be rotated to engage the groove 34 to provide a secure interconnection therebetween, notes FIGS. 3 and 4. A hollow dowel pin 40 extends radially through the barrel wall and sleeve 26 for the purposes hereinafter set forth.
Means for releasably coupling the barrel extension 16 to the barrel 14 is illustrated in FIGS. 5 and 6, and includes a sleeve 42 having a male extension 44 with an annular groove 46 mounted at the second or discharge end of the barrel 14. The extension 16 carries a mating sleeve 48 having a female extension at 50, and a radially extending threaded member 52 for engaging the annular groove 46. A hollow dowel pin 54 extends radially through the sleeve 42 and barrel 14, and a similar dowel pin 56 extends radially through the sleeve 48 and wall of the extension 16. Also, the sleeve 42 includes a sighting member 58 to facilitate aiming of the gun as further described below.
The barrel 14 and extension 16 each comprise a cylindrical wall defining a continuous, uninterrupted tubular passageway which is adapted to closely receive a cylindrical line package 60. The package 60 may for example take the form of the flexible lightweight package disclosed in U. S. Pat. No. 3,006,607, and includes a trailing free line end 62. The barrel l4 and extension 16 are preferably fabricated from a lightweight tubular plastic material, such as polyvinyl chloride tubing having an external diameter of about thineen-sixteenths inches and an internal diameter of about nine-sixteenths inches. The various coupling sleeves are preferably fabricated from a suitable metallic material, and may be secured to the associated barrel or extension in any conventional manner. In this regard, the hollow dowel pins 40, 54, and 56 will alone normally serve to adequately interconnect these members.
In operation, the cylindrical line package 60 is inserted into the loading end of the barrel when the source of compressed gas is uncoupled therefrom as shown in FIG. 3. The coupling sleeves are then interconnected as shown in FIG. 4 such that the line free end 62 is retained outside the barrel. When the valve 20 on the source of compressed gas is actuated by the operator, the surge of gas into the barrel will propel the package 60 through the barrel 14 and extension 16 with sufficient momentum to carry it a significant distance beyond the discharge end of the gun. In this regard, it will be noted from FIG. 5 that the internal diameter of the male extension 44 of sleeve 42 closely conforms to the internal diameter of the barrel and extension, and thereby forms a continuation of the tubular passageway so as to facilitate passage of the line package.
In certain applications, such as for example in casting the line over a suspended ceiling, it is desirable to remove the extension 16 so that the trajectory of the package 60 is coaxial with the barrel 14. In this configuration, the sighting member 58 may be used to aim the barrel such that the package will not strike rafters, ceiling support wires, or other structural members above the ceiling.
It is a further aspect of this invention to provide escapement port means for venting the gas from within the barrel in the event that the barrel is obstructed during entry of the compressed gas thereinto. For example, when a lightweight plastic barrel is employed, it is entirely possible that the pressure of the gas entering the barrel could burst the same if the end were obstructed. In the illustrated embodiment, the hollow dowel pins 40, 54, and 56, serve as the escapement port means to preclude the above possibility. It will be noted from FIG. 4 that the dowel pin 40 is located behind the package 60 at the time of its insertion into the barrel, so that if the barrel is obstructed and the package is unable to move when the gun is fired, the gas will nevertheless have an opportunity to escape without bursting the barrel. If the obstruction is in the extension 16, the ports at 54 and 56 provide supplementary means for venting the barrel.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.
1. An apparatus for casting a line through a relatively nonaccessible area comprising,
a source of compressed gas including valve means for manually releasing a quantity of gas therefrom, a barrel having first and second ends and a cylindrical wall defining a continuous tubular passageway therebetween,
means for releasably coupling said first end of said barrel to said source of compressed gas, and
escapement port means extending radially through said barrel wall adjacent said first end thereof and always being open to atmosphere for venting gas from within the barrel in the event that the barrel is obstructed during entry of the compressed gas thereinto for casting a line to thereby preclude bursting of the same, said escapement port means being of considerably smaller size than said barrel passageway so as not to interfere with the flow of compressed gas through the barrel in the absence of any obstruction in the barrel.
2. The apparatus as defined in claim 1 further comprising a cylindrical line package having a diameter somewhat less than that of said barrel passageway and including a free line end, whereby said line package is adapted to be inserted into said barrel first end when said source of compressed gas is uncoupled therefrom, and said free line end i adapted to be retained outside the barrel upon coupling the same.
3. The apparatus as defined in claim 2 further comprising an arcuately curved barrel extension, and means for releasably coupling said barrel extension to said barrel second end.
4 The apparatus as defined in claim 1 wherein said means for coupling said barrel to said source of compressed gas comprises a first sleeve having a male extension mounted on said barrel first end, a second sleeve having a female extension adapted to receive the male extension and connected to said source of compressed gas, and means for releasably interconnecting said male and female extensions.
5. The apparatus as defined in claim 4 wherein said means for releasably interconnecting said male and female extensions comprises an annular groove extending about said male extension and a radially extending threaded member carried by said female extension and adapted to engage said groove.
6. The apparatus as defined in claim 4 wherein said escapement port means comprises a hollow pin extending radially through said barrel wall and first sleeve, said pin additionally serving to interconnect the same.
7. A line throwing gun for casting a line package or the like through a relatively non-accessible area comprising,
a lightweight barrel having a cylindrical wall defining a continuous tubular passageway adapted to receive a line package in one end thereof,
means at said one end of said barrel for releasably coupling the same to a source of compressed gas, and
escapement port means extending radially through said wall adjacent said one end thereof and always being open to atmosphere for venting gas from within the barrel in the event that the barrel is obstructed durin entry of compressed gas theremto for casting a line pac age to thereby preclude bursting of the same, said escapement port means being of considerably smaller size than said barrel passageway so as not to interfere with the flow of compressed gas through the barrel in the absence of any obstruction in the barrel.
8. The gun as defined in claim 7 wherein said barrel is fabricated from plastic.
9. The gun as defined in claim 7 wherein said coupling means includes a sleeve mounted on said barrel, and said escapement port means comprises a hollow pin extending through said sleeve and said wall, said pin additionally serving to interconnect the same.
10. The gun as defined in claim 7 further comprising sighting means at the end of the barrel opposite said coupling means for facilitating aiming of the barrel.
11. The gun as defined in claim 7 further comprising an arcuately curved barrel extension, means at the end of said barrel opposite said one end for releasably coupling said barrel extension to said barrel and including a sleeve having a male extension mounted on said barrel and a sleeve having a mating female extension mounted on said barrel extension, and wherein said means for coupling said barrel to a source of compressed gas includes a sleeve having a male extension mounted on said barrel and a sleeve having a mating female extension adapted to be mounted to a source of compressed gas.