US3558101A

US3558101A - String tensioning device

Info

Publication number: US3558101A
Application number: US738017A
Authority: US
Inventors: Hubert L Ward
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-06-18
Filing date: 1968-06-18
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26

Abstract

A string tensioning device for use in tensioning a string or cord used in grade level establishment and similar operations, the device including a back plate having a pair of substantially parallel flanges extending normal to the side edges thereof, and having a stake receiving sleeve secured thereto. Secured to one of the flanges and projecting outwardly therefrom in a direction substantially normal to the plane of the back plate is a wagging handle. A crank arm extends parallel to the back plate and is rotatably journaled in the flanges. A stop pin is spaced from, and extends substantially parallel to the crank arm and is slidably mounted in the flanges attached to the back plate. The stop pin has a head thereon and a spring which resiliently opposes axial sliding movement of the stop pin in the flanges. The stop pin is of a length such that it can be forced against the resilient bias of the spring into a position where one end of the stop pin opposite its head is interposed in the path of movement of the crank arm so that the crank arm can be prevented from rotating by contact with the stop pin.

Description

United States Patent [72] inventor Hubert L. Ward Primary ExaminerAndrew R. .luhasz 2326 C Court, Enid, Okla. 73701 Assistant ExaminerDavid R. Melton [2] Appl. No. 738,017 Attorney-Dunlap, Lnaey, Hessin & Dougherty [22] Filed June 18, 1968 [45] Patented Jan. 26, 1971 ABSTRACT: A string tensioning device for use in tensioning a string or cord used in grade level establishment and similar operations, the device including a back plate having a pair of substantially parallel flanges extending normal to the side edges thereof, and having a stake receiving sleeve secured thereto. Secured to one of the flanges and projecting out- [54] STRING TENSIONING DEVICE wardly therefrom in a direction substantially normal to the 6 Cl plane of the back plate a wagging handle. A crank arm exalms, 3 Drawing Figs.

tends parallel to the back plate and is rotatably ournaled m [52] US. Cl 254/51, the fl A stop pin is Spaced f o and extends b 242/100 tially parallel to the crank arm and is slidably mounted in the [51] lnt.Cl 1366f 3/08 flanges attached t0 the back plate. The Stop pin has a head [50] Field of Search 254/51, 64, thereon and a Spl ing which resiliently opposes axial Sliding l86HCv 162, 1-63; 242/96, 99, 100 movement of the stop pin in the flanges. The stop pin is of a length such that it can be forced against the resilient bias of [56] References cued the spring into a position where one end of the stop pin op- UNlTED STATES PATENTS posit 'ts head is interposed in the path of movement of the 73,019 1/1868 Martin 242/ 100 crank rm so that the crank arm can be prevented from rotat- 2,236,305 3/ 1941 Ahlin 242/100 ing by contact with the stop pin.

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PATENTEU JANZSIBYI I 3558.101

fin-E745 INVENTOR. Hues-27' A M44120 BY C5 47 m STRING TENSIONING nravrcra BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to devices of the type used to reeve or wind a length of flexible material upon a drum spindle or other takeup structure. More specifically, the invention relates to a string tensioning device which is adapted for use in establishing a horizontally level string between two stakes for the purpose of establishing grade levels or other reference lines.

2. Brief Description of the Prior Art There are a variety of types of devices and structures which function to permit an elongated flexible line, such as a string, cable or cord to be reeved or wound about a drum, spindle or the like. Such devices include the reels provided in fishing tackle, winch drums provided on shipboard, and clothesline ratchet mechanisms used for tightening clotheslines. In many cases, these devices are complicated structures including selfsetting (automatic) brakes, ratchet mechanisms, tension adjusting devices, and other structural elements having a specialized function required for the particular use to be made of the device.

To my knowledge, however, there does not presently exist an entirely satisfactory device for removing the slack from a lightweight string or cord of the type used in grade level shooting where the string is stretched tautly between two stakes to establish a reference level to be used in building construction and the like. As a result of the unavailability of a simple, yet reliable device which can be used for this purpose, construction personnel continue to tauten the grade level strings manually with the result that either special dexterity is required with some knowledge of knot tying, or an undesirable amount of slack exists in the string between the reference stakes. Moreover, the time required to properly tension the string by the use of knots which will not slip, and which can be effectively tied before loss of tension occurs is a time consuming and tedious operation on large construction projects.

BRIEF DESCRIPTION OF THE PRESENT INVENTION I have now developed an improved string tensioning device which can be quickly and effectively utilized for tensioning a reference or grade level string between two widely separated reference stakes so that the string will effectively run in a straight line and will remain taut during sighting and level establishing operations. Broadly described, the present invention comprises a back plate which carries a stake receiving sleeve at about the center of one face thereof, and which has a pair of parallel flanges secured to the opposite side edges of the plate and extending outwardly from the plate in the opposite direction from the direction of extension therefrom of the stake receiving sleeve. The flanges are provided with spaced pairs of aligned apertures.

One of the pairs of aligned apertures accommodates and journals an elongated leg portion of a crank arm or handle. The other pair of aligned apertures accommodates a stop pin which functions to arrest reverse rotational movement of the crank arm after the string has been tensioned. Positioned around the stop pin and secured between the parallel flanges is a guide sleeve. On the opposite side of one of the flanges from the guide sleeve, and positioned around the stop pin is a suitable spring element which is preferably a helically turned compression spring. The helically turned compression spring bears against a head formed on one end of the stop pin, and biases the stop pin to a position where it does not interfere with the rotational movement of the crank arm.

A final element of the string tensioning device is a wagging arm or handle which is secured to one of the parallel flanges and projects outwardly therefrom in a direction which is substantially perpendicular to the plane of the back plate. The wagging handle permits the entire device to be rotated or wagged from side to side on a supporting stake so that, as the string is wound around the crank arm, it is wound in an even fashion over that portion of the rank arm between the parallel flanges, rather than being accumulated excessively in one location along the crank arm.

From the foregoing general description of the invention, it will be perceived that the present invention achieves one of its most important objectives, i.e., that of providing a simply constructed, mechanically reliable device which can be utilized to quickly tension a grade level string between a pair of reference stakes.

Another object achieved by the invention is that of providing a string tensioning device which can be used by carpenters helpers and other relatively unskilled persons to quickly and reliably tension a grade level reference string at a desired locatron.

An additional object achieved by the invention is the provision of a mechanically reliable string tensioning device which can be quickly mounted on a reference stake used in building construction, and employed after such positioning for drawing taut a string extended from another reference stake a substantial distance therefrom.

In addition to the described objects and advantages, additional objects and advantages will become apparent as the following detailed description of the invention is read in conjunction with the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram depicting the manner in which the string tensioning device of the invention is employed for establishing a grade level.

FIG. 2 is a view in elevation of the string tensioning device of the invention, showing the device supported on a reference stake by means of a supporting device, which supporting device, with the stake, is illustrated in dashed lines.

FIG. 3 is a plan view of the string tensioning device illustrated in FIG. 2, and further showing in dashed lines, the stake upon which it is supported.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring initially to FIG. 1, there is here shown an arrangement of reference stakes and a cord or string which are being utilized for the purposes of establishing a grade level which is to be employed in constructing a building. Two reference stakes l0 and I2 are depicted as spaced horizontally and driven vertically into sloping terrain I4. By the use of a transit or other suitable device, a reference point 16 has been established upon at least one of the stakes 14 with this point being representative of the heights to which it is desired to build a wall, foundation, or the like. A string or cord 18 is tightly secured to the stake 14 at the reference point 16, and is then extended to the stake 10 which is typically positioned at the location of the other corner of the building, or some terminal location or break point in a wall which is to be constructed. Mounted upon the stake 10 in any suitable manner is the string tensioning device 20 of the present invention.

As shown in FIGS. 2 and 3, the string tensioning device 20 includes a back plate 22 which, in the illustrated embodiment of the invention, is substantially rectangular in configuration and has secured thereto a pair of parallel flanges 24 which extend substantially normal to the plane of the back plate. Secured to one side of the back plate 22 so as to project from the back plate in the opposite direction from the flanges 24 is a cylindrical sleeve 26 which has a bore 28 extending therethrough in a direction substantially parallel to the flanges 24.

The flanges 24 are provided with a first pair of aligned apertures 30 which receive an elongated leg 32 of a crank handle designated generally by reference numeral 34. The crank handle 34 also has an end portion flanges 36 secured to the leg 32 to permit the crank arm to be rotated. A pair of spaced, annu- Iar flanges 38 are secured around the leg 32 of the crank handle 34 and are used to retain the crank handle in position between the flanges 24. Spaced downwardly in the parallel flanges 24 from the aligned apertures 30 are a second pair of aligned apertures 40. A guide sleeve 42 which has a bore aligned with the apertures 40 is secured between the flanges 24 and accommodates a stop pin 44 which is extended through the apertures 40 and the guide sleeve. The stop pin 44 carries a head 46 at one end thereof and a helical spring 48 is positioned between the head 46 and one of the flanges 24 nearest adjacent the head. At its end opposite the head 46, the stop pin has a cotter key 47 or other suitable securing means to prevent it from being withdrawn from the guide sleeve 42 and apertures 40. In the use of the string tensioning device illustrated in FIG. 2, the device is shown supported upon the stake 10 by means of a clothespin 50. Any method of securing the tensioning device 20 in a desired vertical position on the stake 10 can, however, be utilized.

OPERATION In the use of the present invention, construction personnel will have set the stakes l and 12 at locations where it is desirable to establish a grade level for purposes of constructing a wall ofa building or the like. By the use of a transit or any other suitable device, a certain reference point 16, representative, for example, of the top of a wall or foundation, is located on one of the stakes, such as the stake 12. The string 18 is then attached to this point of reference on the stake l2, and the string tensioning device 20 is mounted on the stake by passing the stake through the cylindrical sleeve 26. A clothespin 50 or other suitable means for supporting the string tensioning device is clipped on the stake l0, and the tensioning device is located at the approximate location where the under side of the guide sleeve 42 is in horizontal alignment with the reference point 16 on the stake 12. Of course, this will only be an approximation alignment and is later adjusted, as hereinafter explained.

The free end of the string 18 is then passed under the lower side of the guide sleeve 42, through an aperture in the leg 32 of the crank handle 34, or around this leg in any suitable manner so that, as the end portion 36 of the crank handle 34 is grasped and the handle is rotated, the string will be wound upon the leg 32 between the spaced annular flanges 38. Rotation of the crank handle 34 is continued until the string 18 is drawn taut. Reverse rotation of the crank handle is then prevented by pushing on the head 46 of the stop pin 44 to slide the stop pin horizontally through the apertures 40 against the bias of the spring 48. When the end of the stop pin 44 which carries the cotter key 47 has been projected into the path of rotation of the crank handle 34, the handle can be made to contact the stop pin and the tension in the string will be sufficient to cause the crank handle to bear against the stop pin with sufficient force to prevent retraction of the stop pin due to the bias of the spring 48. Then, with the use of a suitable spirit level, the taut string l8 may be varied in its horizontal alignment by sliding the string tensioning device 20 upwardly or downwardly a slight amount on the stake 10 until the string is absolutely horizontal.

Although a preferred embodiment of the invention has been herein described, it will be understood that various changes and modifications to the structure depicted and discussed can be effected without departure from the basic principles which underlie the invention. Changes and innovations of this type are deemed to be circumscribed by the spirit and scope of the invention except as the same may be necessarily limited by the appended claims or reasonable equivalents thereof.

lclaim:

l. A device for tensioning a flexible member comprising:

a back plate;

a stake-receiving sleeve secured to said back plate on one side thereof;

a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned pa apertures, and positioned vertically therebelow;

a crank arm extending through said first paid of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled in said flanges;

a stop pin extending slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the path of rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement; and

a guide sleeve secured between said flanges and surrounding said stopping, said guide sleeve being positioned directly below, and extending substantially parallel to, said crank arm for guiding a flexible member from a vertically lower point to a point on the periphery of said crank arm to facilitate winding said flexible member on said crank arm.

2. A tensioning device as defined in claim 1 and further characterized as including an elongated wagging handle secured to one of said flanges and projecting therefrom in a direction substantially normal to said plate.

3. A device for tensioning a flexible member comprising:

a back plate;

a stake-receiving sleeve secured to said back plate on one side thereof;

a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned apertures;

a stop pin extending slidably tr through said second pair of aligned apertures and parallel to said back plate, said stop i pin being movable between a first position in which it extends into the path of rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement; and

an elongated wagging handle secured to one of said flanges and projecting therefrom in a direction substantially normal to said plate.

4. A device for tensioning a flexible member comprising:

a back plate;

a stake-receiving sleeve secured to said back plate on one side thereof;

a crank arm extending through said first pair of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled in said flanges;

a stop pin extending slidable slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the path or rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement;

a head on one end of said stop pins;

spring means between said head and one of said flanges; and

movement limiting means on the other end 0 of said stop pin a sleeve secured to said back plate on one side thereof and l slidably receiving one of said stakes;

a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection from the back plate of said sleeve, said flanges having a first pair of aligned apertures therethrough anda second pair of v aligned apertures therethrough spaced from said first pair of aligned apertures;

a crank arm extending through saidfirst pair of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled i in said flanges; and

a stop pin extending slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the pate path of rotational movement of said crank arm and a second position in which it is clear of said path 0 of rotationalmovement;

means supporting said tensioning device on said one stake at a selected location; and

an elongated flexible member extending horizontally between said stakesand having one end portion passed through an angle of substantially around said stop pin and wound upon said crank handle.

Claims

1. A device for tensioning a flexible member comprising: a back plate; a stake-receiving sleeve secured to said back plate on one side thereof; a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned pa apertures, and positioned vertically therebelow; a crank arm extending through said first paid of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled in said flanges; a stop pin extending slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the path of rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement; and a guide sleeve secured between said flanges and surrounding said stopping, said guide sleeve being positioned directly below, and extending substantially parallel to, said crank arm for guiding a flexible member from a vertically lower point to a point on the periphery of said crank arm to facilitate winding said flexible member on said crank arm.

3. A device for tensioning a flexible member comprising: a back plate; a stake-receiving sleeve secured to said back plate on one side thereof; a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned apertures; a crank arm extending through said first paid of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled in said flanges; a stop pin extending slidably tr through said second pair of aligned apertures and parallel to said back plate, said stop i pin being movable between a first position in which it extends into the path of rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement; and an elongated wagging handle secured to one of said flanges and projecting therefrom in a direction substaNtially normal to said plate.

4. A device for tensioning a flexible member comprising: a back plate; a stake-receiving sleeve secured to said back plate on one side thereof; a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned apertures; a crank arm extending through said first pair of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled in said flanges; a stop pin extending slidable slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the path or rotational movement of said crank arm and a second position in which it is clear of said path of rotational movement; a head on one end of said stop pins; spring means between said head and one of said flanges; and movement limiting means on the other end o of said stop pin .

5. A tensioning device as defined in claim 2 and further characterized to include: a head on one end of said stop pin; a spring between said head and one of said flanges; and movement limiting means on the other end of said stop pin.

6. A system for establishing a horizontal reference level comprising: a pair of spaced, vertically extending stakes; a tensioning device including: a back plate; a sleeve secured to said back plate on one side thereof and l slidably receiving one of said stakes; a pair of parallel flanges secured to opposed side edges of said back plate and projecting in the opposite direction therefrom as the direction of projection from the back plate of said sleeve, said flanges having a first pair of aligned apertures therethrough and a second pair of aligned apertures therethrough spaced from said first pair of aligned apertures; a crank arm extending through said first pair of aligned apertures and parallel to said back plate, said crank arm being rotatably journaled i in said flanges; and a stop pin extending slidably through said second pair of aligned apertures and parallel to said back plate, said stop pin being movable between a first position in which it extends into the pate path of rotational movement of said crank arm and a second position in which it is clear of said path o of rotational movement; means supporting said tensioning device on said one stake at a selected location; and an elongated flexible member extending horizontally between said stakes and having one end portion passed through an angle of substantially 90* around said stop pin and wound upon said crank handle.