US 3826473 A
A strap adjusting and tensioning device to secure loads under tension which utilizes a ratchet mechanism for slack take-up and tensioning. The device, which may be positioned anywhere along the strap before wind-up is effected, includes a slotted reel having a pair of ratchet wheels cooperating with a radially-disposed, spring-loaded pawl which, in a preferred embodiment, is protected against accidental disengagement by requiring the use of a separate pawl-tripping tool.
Claims available in
Description (OCR text may contain errors)
United States Patent [1 Huber July 30, 1974  SUDABLE BUCKLE ASSEMBLY FOREIGN PATENTS OR APPLICATIONS  Inventor: John Richard Huber, Holicong, Pa. 133.156 4/]907 Germany H 24/71.;  Assignee: Trans Technology Corporation,
Saugus, Calif, Primary Examtner-Richard A. Schacher Assistant Examiner-James L. Rowland  Flled: 1972 Attorney, Agent, or Firm-Synnestvedt & Lechner  Appl. No.: 318,027
-  ABSTRACT 52 us. Cl 254/164 24/712 A strap adjusting lemming device secure  Int 1 B65d 67/62 loads under tension which utilizes a ratchet mecha-  Field of lfi" 24/71 2 nism for slack take-up and tensioning. The device,
24/68 CD 269 1 B61 which may be positioned anywhere along the strap be- I forewind-up is effected, includes a slotted reel having  References Cited a pair of ratchet wheels cooperating with a radiallydisposed, spring-loaded pawl which, in a preferred em- UNITED STATES PATENTS bodiment, is protected against accidental disengagegjigiggg :32: 32;};
acs/5 3i merlit by requiring the use of a separate pawl-tripping 2,816,342 12/1957 Hyre 24/269 too 3.180.623 4/1965 Huber 24/712 X 13 Claims, 8 Drawing Figures 1 SLIDABLE BUCKLE ASSEMBLY This invention relates to strap adjusting and tensioning devices such as are used for securing loads under tension and is particularly concerned with improvements and modifications in the type of device that utilizes a ratchet mechanism for slack take-up and tensioning.
An example of the general construction of a ratchet type strap adjusting and tensioning device is shown in applicants US. Pat. No. 3,180,623 where tensioning is accomplished by handle movement causing rotation of the ratchet device to wrap up the excess strap around a drum. With this prior construction the ratchet windup mechanism is always positioned at a fixed distance from one of the terminal or endattachment fittings and cannot be shifted to various positions along the length of strap so as to accommodate to the size and configuration of the load orbe positioned so that the wind-up mechanism itself will not bear or vibrate against the load or so that the wind-up mechanism is in a-readily accessible position for operation. In addition with the prior construction it is possible to place brittle or fragile loads under such great tension that the load can be damaged.
Accordingly, it is an object of the present invention to provide a ratchet type strap adjusting and tensioning device in the form of a buckle assembly that can be slidably positioned substantially anywhere along the strap beforewind-up is effected.
It is another object of the present invention to provide a ratchet type strap adjusting and tensioning device in which the amount of tension applied to the strap (and inferentially to the cargo) can be regulated and controlled within predetermined limits.
These and other objects and advantages of the invention are obtained by means of a buckle assembly that includes a frame structure carrying a wind-up mechanism; the frame structure having a pair of side plate members spaced to accommodate a strap therebetween, and the wind-up mechanism being in the form of a reel rotatably mounted on an axis extending between said side plate members and providing for holding several wraps of strap for length adjustment and tensioning purposes. The reel structure has a longitudinal slot adapted to receive a strap in a portion thereof intermediate the side plate members, a pair of ratchet wheels, one of which is connected near each end of said reel structure for rotational movement therewith, and a ratchet holding pawl supported on the frame side plate members and slidably movable with respect to the frame in a generally radial direction relative to said ratchet wheels. The holding pawl is spring loaded to bear against the ratchet wheels to permit rotation in one direction and to prevent rotation in the other direction. The wind-up mechanism also has means such as an integral or separate crank for imparting rotational movement to the reel structure; optionally where highly controlled tensioning is desired the crank can be a torque wrench or the like. The frame structure is also provided with a cross member extending between the side plates and aligned generally parallel to the reel axis, said cross member being positioned and adapted to act as a reaction point on the frame against which a strap can be tensioned during and after wind-up.
For a better understanding of the invention, its advantages and the specific objects obtained with its use,
I reference should be made to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of a buckle assembly or wind-up mechanism made in accordance with this invention. I
FIG. 1 is an elevational view of a complete load securing assembly that incorporates a strap lengthening and tensioning device according to the present invention. a
FIG. 1a is a plan view of the strap and end fitting of FIG. 1.
FIG. 1b is an elevational view of a complete load securing assembly having a modified type of threading of the strap through the wind-up mechanism, different end fittings, and the fixed strap end is rotated to show the'end fitting in plan view.
FIG. 2'is an elevational view to an enlarged scale of the slidable buckle unit of the present invention.
FIG. 3 is a plan view of the buckle of FIG. 2.
FIG. 4 is a sectional elevation taken along the line 4-4 of FIG. 3 showing strap threading of FIG. 1 in wrapped adjusted position.
FIGS. 5 and 6 are plan views of the trip plate and pawl of the ratchet mechanism.
Referring to FIG. 1 of the drawing, there is shown a slidable buckle assembly or strap wind-up and tensioning device 10 which includes the frame side plates 11 and 12 and the wind-up mechanism which will be described later. The side plates are spaced apart so that a strap 13 can be threaded through the wind-up mechanism of the buckle. The strap is provided with a pair of end fittings (sometimes hereinafter also referred to as terminal or attachment fittings) adapted to engage a load support or mating fittings carried by the load. The end fittings can be of various types well known in the art, for example keepered hooks, flat hooks, D-rings, track clips, or the like. In FIG. 1 the end fittings are flat hooks l4 and. 15. In FIG. lb the fixed end fitting 14a is a D-ring. The end fitting 14 is secured to one end of strap 13 (hereinafter sometimes referred to as the fixed strap end 16 and the fitting carried thereby as the fixed end fitting). End fitting 15 is of a type having a slot that permits the strap to be threaded through the fitting thereby allowing fitting 15 to slide freely and be positioned at any point along the strap (hereinafter this fitting will be sometimes referred to as the slidable end fitting). The opposite end 17 of the strap 13 is not provided with any terminal fitting and is sometimes hereinafter referred to as the free" strap end. The buckle assembly is positioned on the strap, intermediate the fixed and slidable terminal fittings and, as will be more fully described hereinafter, the free strap end is either doubled back over fitting 15 and threaded through the wind-up mechanism of the buckle, as shown in FIG. 1, or immobilized in a doubled bitted friction grip end fitting 18 that permits rough adjustment of strap length as illustrated in FIG. 1b.
Details of the construction of the slidable buckle assembly will be more clearly understood by reference to FIGS. 2, 3 and 4. There it will be seen that the frame side plates 11 and 12 are spaced apart a distance to accommodate the width of the strap 13 being used to secure the load. The wind-up mechanism includes a reel structure in the form of two similar arcuate segments 19 and 20. When the two segments are positioned together they form a cylindrical drum having a longitudinal slot 19a extending between the side plates. To position and maintain the reel segments a pair of ratchet wheels 21 and 22 are located with one wheel outside each of the frame side plates 11 and 12. These ratchet wheels are provided with apertures in the form of arcuate segments configured to conform and fit the drum segments 19 and 20. Each of the ratchet wheels having a plurality of peripheral teeth, each tooth having one edge 23 (the holding surface) in a substantially radial plane and the other edge 24 having an inclined surface with respect to the radial direction. The side plates 11 and 12 of the frame have suitable circular openings in which the arcuatesegments of the reel are journaled.
To assist in maintaining the spatial arrangements of the reel segments, a pair of spacers a and 20b are employed. These spacers (as can be best seenin FIGS. 3 and 4) are positioned just inside the frame plates having shoulders that conform to the internal curvature of the reel segments and ears that project outwardly through corresponding openings in the reel segments. These ears assist in preventing-inward displacement of the frame side plates. Thus the ratchet wheels and the arcuate shaped reel segments when assembled fit each other in a fashion which maintains the relative position of the reel segments and assures rotation of the drum with respect to the frame side plates upon rotation of the ratchet wheel.
A holding ratchet pawl or dog 25 is supported in frame side plates 11 and 12 by means of slot 26 in each of the side plates. A spacer beam 27 extending between the side plates serves to retain the upper end of the pawl. It will be clearly seen in FIGS. 3and 6 the pawl 25 is made with a transverse bridge portion 28 extending between the frame side plates and two end dog portions 29 and 30 which extend through the slots 26 and engage the teeth of the ratchet wheels. A central guide extension 31 projects outwardly from the bridge portion of the pawl through a suitable slot in the spacer beam 27. A compression spring 32 is supported in position by the extension 31 between the spacer beam and the bridge portion 28 of the pawl thus providing for urging the pawl into engagement with the ratchet teeth. This arrangement prevents rotation of the. reel structure in one direction while permitting rotation in the other direction. The holding pawl is also provided with a pair of guide knobs 50 and 51 on the end dog portions that lie outside frame plates 11 and 12 and prevent lateral shifting of the pawl. To facilitate assembly the frame has an aperture 52 in slot 26 that will pass the guide knobs when they are aligned with said apertures.
The portions of the reel segments 19 and 20 that project beyond the faces of the ratchet wheels 21 and 22 are reduced somewhat in width to form outwardly projecting stubs 33 on each end of the reel segments; these stubs in turn pass through openings in nut members 34 and 35 that are positioned outside the ratchet wheels. Spring pins 36 and 37 extend through the segment stubs outside the nut members and prevent outward displacement of the side plates, the ratchet wheels and the drive nuts. Inward displacement of these parts is prevented by spacer beams 27, 38 and 39 by the ears of spacers 20a and 20b and by the cross member 40, which, as will be described later, also functions as a reaction point against which the strap can be tensioned during and after wind-up.
Nut members 34 and 35 shown in the illustrated embodiment are hex-nuts but they can have any desired configuration capable of mating in a driving engagement with a radially projecting crank or lever arm for actuating the ratchet mechanism such as the illustrated torque wrench 41.
In using the load securing assembly i.e. the strap,
I the associated attachment fittings and the buckle the for retaining the article to be secured. The buckle is slid to a suitableposition where it will not bear or vibrate against the load or where it will be readily accessible for operation. The slack is pulled through the reel slot by manually pulling on the free strap end 17, and tightening action is initiated by turning the wrench about the reel axis to' actuate the ratchet. When a single turn of strap has been made on the reel, the strap is held against slippage by virtue of the tension load in the loaded portion of the strap applying pressure to the unloaded. end of the strap lying underneath it as it wraps on the drum. Turning movement of the wrench about the reel axis rotates the wind-up drum in the tensioning direction (shown by the arrow on the ratchet wheel in FIG. 2) until the desired tension in the strap is obtained.
The degree of precision within which tension may be developed will be determined by the number of teeth on the ratchet; the greater the number of teeth the more precise the tension adjustments. Where desired the total tension applied to the strap can be controlled and regulated as shown in FIG. 3 by employing a torque wrench 41 as the drive crank. The torque wrench can be one that will permit varying but measured torques to be applied or a preloaded wrench that becomes inactivated whenever a predetermined torque has been exceeded.
In order to prevent the buckle from cockingon the strapduring tensioning and to maintain the tensioned strap runs on both ends of the buckle in substantially the same plane, a strap reaction-point on the frame must be provided away from (behind) the tensioning direction. Cross member 40 is such a reaction point. In the illustrated embodiment it is a circular cylinder supported in the frame side plates on an axis parallel to the reelv axis but horizontally and vertically offset therefrom. As illustrated frame edge 42 is'considered to be 'the bottom of the buckle, and the ratchet mechanism is adapted to only turn in a clockwise direction, the pawl preventing counterclockwise movements. In this arrangement, the axisof the reaction member 40 is ahead of and below the level of the reel axis and the top of the ratchet wheel moves away from the crossmember up'on rotation from the 9 o'clock to 3 o'clock position and provides a tensioning reaction point for a strap passing beneath it and into the reel slot. This positioning, in cooperation with the strap threading slot formed by cross beams 27 and 38 at the opposite end of the buckle, tend to maintain the strap substantially planar at both ends of the buckle.
When it is desired to release the tension from the strap, the holding pawl 28 is disengaged from the ratchet teeth thereby freeing the drum so that it can unwind in a direction to release the tension in the strap.
This disengagement of the pawl can be accomplished in various ways well known in the art, frequently by an outwardly projecting flange or knob on the pawl bridge that can be manually grasped to trip the pawl. However, in the preferred embodiment of the invention illustrated in the drawing the pawl tripping means is constructed so that it is extremely difficult for the holding pawl to become disengaged accidentally by some force being inadvertently applied to the pawl tripping mechamsm.
The pawl mechanism of this invention is so constructed that a separate tool is required to trip the ratchet unloading mechanism. Cross beam or trip plate 39 extends across the frame, the edge 43 of beam 39 that is radially furthest away from the reel axis is notched 44. Trip plate 39 and the holding pawl 25 are positioned relative to one another so that the pawl bridge edge 45 closest to the reel axis and the notch edge 46 of the spacer beam 26 are parallel and in more or less vertical I claim:
l. A strap length adjusting and tensioning device adapted to be positioned at any point along a strap,
said device having a frame structure and a wind-up I mechanism:
said frame structure including a pair of side plate members spaced to accommodate a strap therebetween,
said wind-up mechanism including a reel structure rotatably mounted on an axis extending between said side plate members and providing for holding several wraps of strap for length adjustment and tensioning purposes,
said reel structure having a longitudinal slot adapted to receive a strap in a portion of the reel structure intermediate the side plate members,
a pair of ratchet wheels, one of which is connected near each end of said reel structure for rotational movement therewith,
a ratchet holding pawl supported on the frame side plate members and slidably movable with respect to the frame in a generally radial direction relative to said ratchet wheels and spring loaded to bear against the ratchet wheels to prevent rotation of the reel in one direction while permitting rotation in the other direction,
said wind-up mechanism further having means for imparting rotational movement to the reel structure,
said frame also having a cross member extending between the side plates and aligned generally parallel to the reel axis, said cross member. being positioned and adapted to act as a reaction point on the frame against which a strap can be tensioned during and after wind-up, and said frame also having a strap threading slot at the end of the frame opposite the end of the frame on which said cross member is positio'ned.
2. A strap adjusting and tensioning device according to claim 1 wherein the means for imparting rotation to the reel comprise coupling means adapted to be engaged by mating coupling means of a crank member.
3. A strap adjusting and tensioning device according to claim 1 including tool actuatable means for tripping the holding pawl.
4. In combination, a strap and a strap adjusting and tensioning device according to claim 1.
5. In combination, a strap and a strap adjusting and tensioning device according to claim 2.
6. In combination a strap and a strap adjusting and tensioning device according to claim 3,
7. In combination a strap, a strap adjusting and tensioning device according to claim 2, and a crank member adapted to be coupled to the rotation imparting means.
8. A combination according to claim 7 in which the crank member is a torque wrench.
9. A load securing assembly including a strap, a pair of attachment fittings and a strap adjusting and tensioning device according to claim 1 positioned on the strap between the attachment fittings with the strap passing beneath the cross member, through the slot of the reel, and through the frame threading slot.
10. A load securing assembly according to claim 9 wherein one of said attachment fittings is fixed to said strap and the other attachment fitting is slidably positionable on said strap.
11. A load securing assembly according to claim 10 wherein the strap end carrying the slidable attachment fitting is doubled back and also passes through the slot of the reel.
12. A load securing assembly including a strap, a pair of attachment fittings and a strap adjusting and tensioning device according to claim 2 positioned on the strap between the attachment fittings with the strap passing beneath the cross member, through the slot of the reel and through the frame threading slot.