Patent Application
20150375371
1. Field of the Invention
This invention relates to pliers. Specifically this invention relates to pliers useful in heavy-duty operations.
2. Background and Discussion of the Prior Art
In the art related to pliers particularly for gripping pipes and like plumbing fixtures, it was known to provide slip joint adjustable jaws in parallel disposition such as is disclosed in U.S. Pat. No. 4,890,519, granted Jan. 2, 1990 to Le Duc; and U.S. Pat. No. 5,176,049, granted Jan. 5, 1993 to Neff. These parallel facing jaws generally did not provide sufficient grip to hold and rotate seized or tightened cylindrical workpieces such as pipes and bars. Such tools, when engaging a seized or tightened cylindrical pipe or bar, would readily slip when a large torque force was exerted tangentially to the pipe or bar axis. The heavy-duty tool art desires pliers with greater non-slip gripping forces than heretofore. More recent pliers and pipe wrenches provide V-shaped, curved or arcuately opposed jaw faces that encompass the cylindrical pipe or bar, such as is disclosed in US2009/0133540, published May 28, 2009 to Yu, and US 2002/0121162 published Sep. 5, 2002 to Dong, in an attempt to provide sufficient torque grip slip forces. Such prior art pliers and wrenches were not of practical design and costly to manufacture, and the jaws having curvatures or V-shaped angular constructions did not operably fit differently sized pipes and bars.
The heavy-duty tool art desires a pliers that has high torque grip capability without slippage on differently sized seized or overly tightened cylindrical workpieces, such as pipes or bars , and is of non-complex design and construction, is readily manufactured, and yet safe and practical use. The present invention provides a solution to these heavy-duty pliers art needs.
The invention, in one aspect, is a slip-joint pliers having opposed parallel jaws with a specific cross-hatch pyramidal teeth construction. The pliers develops a high torque grip slip force on a seized or overly tightened cylindrical workpiece such as a pipe or bar. The pliers in one embodiment includes a tongue in groove type slip-joint construction. The pliers in one further aspect provides that when a 45 lb force is exerted on the handles through a 5 to 6 inch moment arm on a ¾ inch cylindrical workplace, a 200 to 300 lb. torque is developed without slippage of the jaws on the cylindrical workpiece. The cross-teeth or cross-hatch teeth are disposed at between 110° and 150°, and preferably at about 130°. The rows of cross-hatch teeth are spaced at less than about 10 teeth/inch on each jaw face. The pliers is relatively compact being no greater than about 10 to 12 inches in length with a moment arm of no more than about 5 to 6 inches. The afore-described pliers is a compact yet heavy-duty use tool, that develops a torque grip slip force greater than similarly sized prior art pliers.
The invention, in another aspect, is a method for unloosening a seized or overly tightened workpiece, which includes the steps of (a) providing a pliers having a first member having a proximately disposed handle and a distally disposed jaw having a face; and a second member having a proximately disposed handle and a distally disposed jaw having a face, and having a slot disposed in one of the handles, with a pivot pin slidably operably disposed in the slot with the jaw faces in parallel operable disposition; and each jaw face has first and second pluralities of pyramidal teeth in angular disposition, and (b) grippingly engaging the workpiece with the pliers jaws, and then (c) moving the pliers to unloosen the seized or overly tightened workpiece.
The term “torque grip slip force” as used hereinbefore and hereinafter means the maximum torque force that is developed on a cylindrical workpiece without slippage of the pliers jaws grippingly engaged on the cylindrical workpiece.
Referring to the FIGS. there is shown pliers 10 of the present invention. Pliers 10 includes front member 11 and rear member 12. Members 11 and 12 are operably connected by pivot pin 13 slidably disposed in elongate slot 14 with a tongue 15 and groove 16 construction, as is well-known in the pliers art. Member 11 includes distal end 16 and proximate end 17, handle 18 and jaw 20. Member 12 includes distal end 46, proximate end 47, handle 23 and jaw 25.
Jaws 20 and 25 are contactingly engaged at points 26 and 27 in the fully closed or inoperable disposition (
Referring specifically to
It has surprisingly been found that a relatively compact pliers of no more than about 10 to 12 inches in overall length as measured from 46 to 47 (
It is well-known in the art related to gripping tape undergoing sidewards and twisting forces, to provide fine cross-teeth to hold the tape and avoid damage to the gripped surfaces. Such fine cross-teeth jaw construction fish tape gripping pliers are disclosed in U.S. Pat. No. 7,395,740 and U.S. Pat. No. 7,415,913 to Reckhart, the named inventor in the present application.
The fish tape pliers art as exemplified in U.S. Pat. No. 7,395,740 and U.S. Pat. No. 7,415,913, required a fine or narrow airway of teeth of about 17 to 32 teeth/in, to provide sufficient non-slip grip under twisting and cross-wise forces in fish tape operations. It was surprisingly found with respect to the present invention that 130° angular array of no more than about 10 pyramidal teeth/in. provides an exceptionally high torque grip slip force.
A series of resultant torque force tests were undertaken. The test apparatus included a ¾ inch steel bar held in a vise at one end, and a torque meter encompassed bar adjacent the vise. The pliers undergoing the test were contactingly engaged at the midpoint of the steel bar, and an elastic member encompassed the pliers handles to hold the pliers in place in gripping engagement with the steel bar. An SAB force applicator/meter applies a downward force on handle grip point, as shown by arrow C at recess 80 on the pliers 10 (
The tools undergoing the test were a Channellock 430 model (the “430” pliers) in an industry standard 10-inch tongue and groove pliers with a 5.5 movement arm and standard parallel rows of teeth. A Channellock 430 pliers was cross-cut to form the pyramidal teeth configuration of the present invention as afore-described and shown in the FIGS. (the “430X” pliers) as afore-descried and shown in the FIGS. A Channellock 440 model is an industry standard 12 inch tongue and groove pliers with a 6.5 movement arm and standard parallel rows of teeth (the “440” pliers). A Channellock 440 pliers blank was cross-cut to form the pyramidal teeth configuration (the “440X” pliers) as afore-described and shown in the FIGS. A Channellock 432 V-shaped opposed jaws 10-inch torque and groove plies with a 5.5 movement arm with standard parallel rows of teeth (the “432” pliers) also underwent the test.
A 45 lb. force was applied to the handle of each of the foregoing pliers and the resultant torque grip slip force was measured. The results are shown in Table I.
The pliers of the present invention, viz. the 430X and 440X pliers, provide a 200 to 300% improvement in the slip grip torque force over the standard pliers in the industry, and more than about 300% improvement over the angled or V-shaped opposed jaws pliers of comparable size and handle configuration.
Although the invention has been afore-described in relation to its preferred embodiment, it is to be understood that many other modifications and variations can be made without departing from the scope of the present invention. It is therefore, intended that the appended claims cover such modifications and variations within the scope of the invention.
This application is a continuation-in-part of Ser. No. 14/156,511, filed Jan. 16, 2014, which application is incorporated herein in its entirety by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14156511 | Jan 2014 | US |
| Child | 14850242 | US |
