Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
2001-06-11
2004-11-09
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C227S137000
Reexamination Certificate
active
06813977
ABSTRACT:
FIELD OF INVENTION
This invention relates to a screw gun. More specifically, the invention relates to a screw gun including a driving unit fitted with a slidable cartridge holder adapted for receiving and indexing a separate cartridge containing a plurality of screws. The invention further relates to the replaceable cartridge containing the plurality of screws for use in a screw gun. The invention allows for the loading and insertion of a plurality of screws from a cartridge without requiring a worker to handle and insert the individual screws into the driver.
BACKGROUND OF THE INVENTION
This invention relates to a screw gun and method for loading and inserting screws. There is a need in industry for a screw gun which can load and insert a plurality of screws without a worker having to individually handle each screw. The screw gun should be compact, lightweight and easy to use in the field. Specifically, for example, in the heating, ventilating and air conditioning (“HVAC”) industry, hex-head self-tapping screws with integral washers, sometimes known as “tech screws”, are used for connecting adjacent sections of sheet metal duct. A majority of the time, the task of connecting these adjacent sections of sheet metal duct occurs on lifts and in confined spaces. An HVAC worker will insert anywhere from about 2 to 10 screws per duct joint. The present method used by the HVAC worker to insert a tech screw involves the use of a drill with magnetic hex socket in the drill chuck and an apron full of tech screws. The HVAC worker must pick up an individual tech screw from his apron. He then by hand places the screw into the hex socket, and then inserts the screw through the sections of duct. The process is made more difficult when the worker wears gloves, not uncommon in this industry. It is estimated that up to 30% of the screws intended to be inserted into sheet metal duct sections are dropped and lost by the worker as he or she attempts to hand place a screw in the hex socket. Thus, the present method is laborious, slow and costly. Accordingly, there is a need in the HVAC industry, and other similar industries, for a lightweight, portable screw gun that will increase the productivity of workers and decrease costs associated with the time consuming manual insertion of screws in the gun and the cost associated with lost screws.
Screw guns for feeding and locating fasteners for insertion into a workpiece are generally known in the art. However, these designs are not practical as they are overly complex and, therefore, costly, and they are bulky and not easy to use, especially when working in confined spaces. For example, known power operated devices for feeding and locating fasteners, like those disclosed by U.S. Pat. No. 5,031,489 to Young et al. and U.S. Pat. No. 5,015,127 to Hockman, require that a fastener driver be connected to an air supply to power the device and connected to a hopper or the like in order to continuously feed the driver with fasteners. Such devices limit their application because of their lack of mobility and unwieldiness. Accordingly, such devices are not practical for use in confined spaces, such as when working on a scaffolding or a lift. Similar devices for feeding and locating fasteners have strips which carry the screws and are swingedly suspended from the device, such as disclosed in U.S. Pat. No. 3,910,324 to Nasiatka and U.S. Pat. No. 4,581,964 to Takatsuru. These devices are also not practical for use in confined spaces because of the added weight and awkwardness associated with the devices.
U.S. Pat. No. 4,936,169 to Parsons discloses a portable device for positioning and inserting fasteners wherein an applicator is positioned adjacent to a positioning mechanism containing a rotatable cylinder which includes a plurality chambers for housing fasteners. However, the Parsons device also includes a number of drawbacks including that it is bulky, the operator is required to align a screw with the applicator by hand before he can insert a second screw into a workpiece, and the screw is not readily visible prior to insertion.
The present invention solves the problems of the prior art devices as discussed hereafter.
PRIMARY OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION
It is a primary object of the invention to provide a screw gun capable of carrying a number of screws in an easily loadable and removable cartridge, thereby allowing a worker the ability to insert multiple screws in a workpiece without ever having to handle the individual screws.
It is a further primary object of the invention to provide a cartridge for carrying a multiplicity of fasteners, such as screws, which is easily loaded and removed from a screw gun. The fasteners are releasably held in the cartridge until engaged by the driver of the screw gun.
It is a further primary object of the invention to provide a screw gun for inserting fasteners, such as screws, having a novel cartridge holder for locating the fasteners from a cartridge into the driver of the screw gun.
It is a further object of the invention to provide a screw gun having a driver and guide post with a cartridge holder slidably arranged thereon for carrying a rotatable cartridge containing a multiplicity of screws. The screw gun components cooperate with the cartridge for quickly and efficiently locating fasteners, such as screws, on the driver for subsequent insertion into a workpiece.
It is another object of the invention to provide a screw gun having a cartridge holder which will automatically align a cartridge containing a multiplicity of fasteners, such as screws, so that a worker can easily and quickly change the cartridge in the screw gun. The cartridge upon insertion into the gun will automatically be aligned for locating and loading a fastener.
It is another object of the invention to provide a screw gun having a cartridge holder which will automatically index and align a cartridge containing a multiplicity of fasteners, such as screws, by pump action so that a worker can easily and quickly insert a number of fasteners from the cartridge without having to handle the individual fasteners or adjust the cartridge.
It is another object of the invention to provide a screw gun which is simple in construction, easy to manufacture and durable. The screw gun is light-weight, portable and can be used in confined spaces, such as on a lift, to insert tech screws in duct work. The invention provides for an easily loadable and unloadable cartridge holding 8 to 10 screws.
It is another object of the invention to provide a screw gun having a driver that projects sufficiently beyond the cartridge holder such that the screw is plainly visible to the worker for easily locating the position of the screw into the workpiece.
It is a further object of the invention to provide a screw gun having the driver projecting beyond the cartridge holder to allow insertion of screws in tight spaces.
It is another object of the invention to provide a screw gun where the center of the gravity of the gun remains close to a worker's wrist to make the gun easy to hold and well balanced. This provides a screw gun which is easy and comfortable to use for the worker.
The screw gun of the present invention comprises a driving unit; an elongated driver for receiving a fastener such as a screw; a guide post connected to the driving unit and having a cam path; a cartridge holder slidably mounted on the guide post in cooperation with the cam path of the guide post, and a cartridge carrying a multiplicity of fasteners. In this specification, the fasteners will hereafter be referred to as screws with the understanding that other fasteners may be used with the invention.
In operation, the screw cartridge is inserted into the cartridge holder of the gun and it is automatically aligned so that a chamber of the cartridge is in alignment with the driver of the gun. A screw is loaded from the cartridge to the driver by pump action. By pump action, we mean that the cartridge holder is manually moved inward toward the gun to load a screw into the driver and for subsequ
Daw David E.
Goodhue William V.
Mathieu David L.
Breiner & Breiner L.L.C.
Davicorp Inc.
Smith James G.
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