US3280893A

US3280893A - Window blind operating device

Info

Publication number: US3280893A
Application number: US379999A
Authority: US
Inventors: Robert O Webb; Sakamoto Shitomi
Original assignee: WEBB TEXTILES Inc
Current assignee: WEBB TEXTILES Inc
Priority date: 1964-07-02
Filing date: 1964-07-02
Publication date: 1966-10-25
Anticipated expiration: 1983-10-25

Description

0t- 25, 1956 R. o. WEBB ETAL 3,280,893

WINDOW BLIND OPERATING DEVICE Oct. 25, 1966 R. o. WEBB ETAL 3,280,893

WINDOW BLIND OPERATING DEVICE Filed July 2, 1964 2 Sheets-Sheet 2 INVENTORS United States Patent O 3,280,893 WINDOW BLIND OPERATING DEVICE Robert 0. Webb, Glendale, and Shitomi Sakamoto, Pasadena, Calif., assignors to Webb Textiles, Inc., Pasadena, Calif., a corporation of California Filed July 2, 1964, Ser. No. 379,999 11 Claims. (Cl. 160-281) This invention relates to a window blind operating de vice and, more particularly, to a device for raising and lowering window blinds to and from positions which are higher than a person can reach.

In many modern buildings, especially where large expanes of glass are used, each window in the building customarily is tted with an adjustable window blind. In many cases it is desired that the blinds -be raised to and lowered from positions which are beyond the reach of a person. Where the blinds are positioned labove the normal reach of a person, the blinds often are not adjusted downwardly when adjustment .is required. Also, where the blinds are raised only to the extent that a person can comfortably reach, the blinds usually are not raised to a uniform level and this presents an unaesthetic appearance to persons viewing the building.

This invention provides a novel and effective device for operating a window blind so that the blind may be lowered from or raised to a position beyond the reach of a person operating the blind. Special training is not required for the successful use of the device and thus the blinds may be used without encountering the above-mentioned problems.

The novel blind operating device preferably is used with window blinds which include a vertically disposed elongated exible sheet of window covering material. A sheet coiling mechanism is mounted across an upper extent of the window and is secured to an upper end of the sheet. A hollow rigid bar is secured to the lower end of the sheet. Each end of the bar carries a guide means adapted for engagement in a corresponding one of a pair of guide tracks disposed adjacent the sheet. Resilient means are disposed in the bar and are operable for biasing the guide means into engagement with the guide tracks to secure the bar from motion relative to the tracks. The blind also includes release means for the guide means. The release means includes a pair of spaced apart aligned tabs which extend laterally from the bar and which are relatively movable toward each other against the bias of the resilient means to eifect the disengagement of the guide means from the guide track. Each tab has a surface exteriorly of the bar which opens toward the adjacent guide means.

Generally speaking, the present invention provides a device for operating a window blind preferably of the type described above. The device includes an operating member which defines a pair of substantially straight rigid rails having first and second ends. The device also includes means for mounting the rails in substantially fixed relation to one another so that the rails are disposed adjacent each other in substantially coplanar relation. The mounting means 'also positions the rails so that the rst ends of the rails are spaced apart laterally of the rails a predetermined distance. The rails converge toward each other to the second ends of the rails. The rails and their mounting means are carried at the end of an elongated handle.

The above-mentioned and other features of the invention are more fully set forth in the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. l is a perspective view showing a window blind with which the present invention has utility;

FIG. 2 is a cross-sectional elevation view of the 4bar se- ICC cured to the lower end of the window covering shown in FIG. 1;

FIG. 3 is an enlarged elevation view of a bilnd operating device according to this invention;

FIG. 4 .is an enlarged plan view of another embodiment of the blind operating device according to this invention; and

FIG. 5 is a perspective view of yet another embodiment of the blind operating device according `to this invention.

With reference to FIG. l, a window blind 9 includes a fabric window covering sheet 10 which is secured along one end to a hollow roller 11 and is secured along its other end to a rigid tubular drawbar 12. While shown in the drawing as a continuous piece of fabric, it will be understood that the sheet of window covering can be m-ade from a plurality of articulated horizontal slats joined together by fabric bands or textile bindings.

Roller 11 is mounted above a window by inserting bar projection 13 and rod projection 14, protruding from opposite ends of the roller, into brackets (not shown) mounted on opposite edges of the Casement or upon the opposing surfaces of the opening in which the easement is set. The bracket which supports bar projection 13 is slotted to accommodate the projection and to restrain it from rotation upon rotation of the roller. The other bracket has a central aperture to accommodate rod projection 14 so as to permit its free rotation. Such brackets are well known and are commonlyV used with shade rollers of the type shown.

Roller 11 is a commercially available device which includes a torsion spring (not shown) in its interior. One end of the torsion spring is connected to bar projection 13 and the other end of the spring is secured to the roller. Bar projection 13 is rotatable in the end of the roller. Accordingly, as fabric sheet 10' is lowered or unwound from Iaround the roller, the roller rotates and loads the torsion spring. The torsion spring thus biases the roller so that there is .imposed on the window blind an upwardly acting force which tends to recoil the blind on the roller.

Tubular drawbar 12 includes

guide elements

15, 16 which are carried by the exterior ends of plunger assemblies 17, 18 (see FIG. 2) which are reciprocably mounted in the drawbar.

Guide elements

15 and 16 are fitted within

vertical guide tracks

19 and 20, respectively. The guide'tracks are mounted either on the walls of the opening in which the easement is set or upon the easement itself. The guide tracks are vertically aligned with one another and extend along at least a portion of the vertical extent of sheet 10. As seen in FIG. 1, guide track 19 preferably is a channel having sides 21 and 22 and a pair of inwardly extending

lips

23, 24 to constrain the guide means within the tracks during up and down movements of the drawbar. However, whiley not as convenient, the guide tracks can also be open channels without the inwardly extending lips.

A plurality of stops 25 are spaced along the vertical extent of the guide tracks in horizontally aligned locations. Preferably the stops are spaced 6 inches apart to provide an optimum number of preselected positions of adjustment for the window covering vertically of the Window.

As shown in FIG. 2, a pair of

plunger assemblies

17 and 18 are reciprocably mounted in a drawbar 12 and extend from opposite ends of the drawbar. Each plunger assembly includes an elongate rod member 28 disposed adjacent the middle of the drawbar so that the inner ends 29 of the rod members open toward each other. The inner ends of the rod members are disposed opposite an elongated slot 30 which is formed through the drawbar intermediate its ends and which extends lengthwise of the drawbar. A small diameter externally threaded stub 31 extends axially from the opposite end of each rod element 28. An internally threaded tubular member 32 having an outer diameter slightly less than the inner diameter of the drawbar is engaged with each stud 31 and is, in effect, an adjustable extension of its rod element. Each tubular member 32 extends from the adjacent end of drawbar 12 and carries at its outer end one of

guide elements

15, 16.

A pair of laterally extending tabs 33 are disposed exteriorly of the drawbar adjacent slot 30. Each tab is secured to a corresponding one of rod elements 28 by a screw 34 which is passed through slot 30 into threadable engagement with the rod element. Each tab has a concave surface 35 which opens toward the guide element connected to the plunger assembly with which the particular tab is associated.

A compression spring 36 is disposed inside the drawbar and is biased between the inner ends of the pair of plunger assemblies as shown in FIG. 2. Spring 36 biases the plunger assemblies away from each other so that the guide elements are urged into intimate engagement with the guide tracks to maintain the drawbar in a particular position vertically of the guide tracks against the upwardly acting force imposed upon the blind by the torsion spring in roller 11. Since the horizontal spacing between the

tracks

19 and 20 may vary from window to window, tubular elements 32 are adjustable along studs 31 to adjust the overall length of the drawbar assembly.

The provision of horizontally alinged stops 25 in

tracks

19 and 20 provides predetermined settings for the position of drawbar 12 vertically of the window so that the lower ends of several adjacent window blinds may be horizontally alinged, thereby presenting a neat and orderly appearance when the windows are viewed from a distance. Accordingly, corresponding stops are fixed at equal distances above a xed level.

Each stop 25 has a thickness laterally of guide track 19 substantially less than the distance between the base of the track and

lips

23, 24, so that guide element may be moved inwardly toward the central portion of the drawbar and passed beyond the stop. Tabs 33 are moved toward each other to retract

plunger assemblies

17 and 18 toward each other and to release the

guide elements

15 and 16 from their tracks.

In modern buildings it is quite common for the windows with which window blinds 9 are used to be of considerable vertical extent. Moreover, it is often desired that the lower ends of sheets 10 be disposed at heights higher than those which a person can conveniently reach. For reasons of safety it is desirable that the person not be required to stand on a chair, for example, in order to operate the window blind. This invention, however, provides a very simple yet highly eective apparatus for operating window blinds of the type described above.

Referring to FIG. 3, a window blind operating device 55 is shown. The device includes an operating head or yoke 56 which is secured to one end of an elongated handle 57. The operating head is fabricated from metal or rigid plastic and is of substantially planar configuration and preferably is coplanar with handle 57. The operating head is shaped to resemble an isosceles triangle and encloses an open central portion 58. The operating head defines a frame around the open central portion of the head. The frame includes a base portion 59 which is substantially straight and is disposed transversely of the elongate extent of handle 57. The frame base portion has opposite ends 60 from which extend a pair of frame leg portions or rails 61. The rails are substantially straight and converge -toward one another proceeding away from the base of the frame. The rails are connected together at a location 62 spaced opposite from the handle. The rails have opposing surfaces 63 which are engageable with the surfaces 35 of drawbar tabs 33. The distance between base ends 60 is such that the diverging ends of the rails are spaced from each other a distance sufficient to enable surfaces 63 of the rails to be engaged with tab surfaces 35 when

guide elements

15, 16 are spaced apart from each other the maximum distance permitted by the distance between guide tracks 19, 20. The spacing of the diverging ends of the rails must be somewhat greater than the maximum distance between tab surfaces 35 since the tabs curve away from each other. Although rails 61 of the operating head frame are shown connected t0- gether at a location remote from handle 67, this need not be the case. It is required only that the rails at the point of closest convergence thereof be spaced apart a distance no greater than the distance between the tab surfaces 35 when the guide means are moved toward each other the maximum distance permitted either by the restraining action of

track lips

23, 24 or by the compressability of drawbar biasing spring 36 in cases where the guide tracks are not provided With

lips

23, 24.

In order that the use of operating device 55 may be more fully understood, let it be assumed that drawbar 12 0f blind mechanism 9 is positioned at a location above the reach of a person who desires to lower the blind. Head 56 of the operating device is engaged with tabs 33 of the drawbar so that the concave surfaces of the tabs are brought into engagement with the surfaces 63 of the operating head. When the rails first engage the tabs, the tabs occupy the positions shown in dotted lines in FIG. 4 relative to the operating head. Handle 57 is then pulled downwardly with a force F so that the rails of the operating head slide downwardly relative to the tabs and force the tabs toward one another against the bias of spring 36. As this occurs a normal force N is generated between each rail and tab as shown in FIG. 4. As the tabs are moved toward each other, the guide elements of the drawbar are moved out of engagement with the guide tracks until the guide elements are clear of stops 25. If the'force applied downwardly on handle 57 exceeds the upward force applied to the drawbar by the roller torsion spring, then the drawbar will be drawn downwardly and the window cover will be lowered. If the drawbar is to be lowered to a position which is still above the height the operator can reach, the operating head is given a sharp upward movement when the drawbar is at the desired location so that the operating head is quickly disengaged from the tabs and the guide elements are thereby forcibly moved into engagement with the guide tracks.

Operating device 55 is also useful in raising the window covering to a location above the reach of the person raising the blind. The operating head Iof the device is engaged with tabs 33 of the drawbar as before. A downward force F is applied to the handle to draw the tabs together and thereby effect disengagement of the

guide elements

15, 16 from

tracks

19, 20. In this case, however, the downward force applied to the handle is less than the upward force applied to the drawbar by the roller torsion spring. Once the guide elements have been disengaged from the tracks, the handle is raised until the drawbar is at the desired location. Upward movement of the drawbar is then ceased momentarily and the handle 57 is then moved upwardly sharply to quickly disengage the operating head from tabs 33.

In order that a downward force on handle 57 of less magnitude than the upward force imposed on drawbar 12 by the the torsion spring maybe sufficient to move tabs 33 together against the bias of spring 36, the bias of spring 36 should not be any greater than is necessary to impose a force 'between the guide elements `and the tracks sufficient to assure that the drawbar does not slide upwardly under the urging of the roller torsion spring. Further, the angle between rails -61 is an angle which assures that the force which must be applied downwardly of the operating head handle 57 to generate forces N sufiicient to move the plunger assemblies toward each other against the bias of spring 36 is not greater than the upward force acting on the drawbar for any position of the drawbar relative to roller 11. It will be seen that the proper angle of convergence of the rails is related to the forces developed by spring 36 and by the roller torsion spring.

In the foregoing description of the use of operating device 55 for raising a window covering, it was assumed that the window -covering was spring biased for upward movement. In many cases, however, the window covering to which drawbar 12 is connected may not be secured to a spring 4biased coiling mechanism with the result that the drawbar must be pushed upwardly. In such a case, operating device 65 shown in FIG. 4, may be used. Operating device 65 includes an operating head 66 which has a pair of converging leg portions or rails 67 which are connected together at their point 68 of closest convergence. As indicated above, however, the rails need not be joined at their upper ends. Rails 67 have spaced apart lower ends 69 which are connected to a base portion 70 of operating head 66. The base portion has a central portion 71 from which a .pair of legs 72 diverge to ends which are coextensive with the ends of rails 67. A handle 73 is secured to central portion 71 and preferably lies in the plane of the operating head. Preferably rails 67 and legs 72 are of equal lengths so that the operating head has a diamond or rhombical configuration.

Operating device 65 is used in the manner described above to lower a window covering which is not spring biased. To raise such a window covering, however, the tabs associated with the plunger assemblies of the drawbar are engaged between the opposing surfaces of legs 72 and shaft 73 is urged upwardly to force the tabs together. Handle 73 is then raised to push the drawbar upwardly to the desired position.

FIG. 5 shows an operating device 75 which has an operating head 76 configured like operating head 56 of operat-ing device 55. A shaft 77 extends from the base of operating head 76 and preferably lies normal to the plane of the operating head. A handle 78 is connected to the shaft. Operating head 76 may be used in accord with the procedure described with respect to the device shown in FIG. 3 in instances where a window blind has a torsionally loaded roller at its upper end. Also, it may be used in accord with the procedure described with respect to FIG. 4 where the blind does not have a spring loaded roller connected to its upper end; in this case, handle 78 is turned so that operating head 76 is disposed below shaft 77 when the -blind is to be raised.

Both operating head 76 in its inverted condition and operating head 66, however, may be used to raise a spring loaded blind. The operating head is engaged with tabs 33 and is pushed upwardly thereagainst to move the tabs together. The blind then moves upwardly because of the bias imposed on the blind by the roller torsion spring. The operator follows the blind upward with the operating device to keep

plunger assemblies

17, 18 retracted, but at the location at which the blind is to be raised the operator disengages the operating device from tabs 33 so that

guide elements

15, 16 engage

tracks

19, 20 to secure the -blind in its raised condition. If the blind should advance upwardly faster than the operator is able to follow with the operating device, the tabs will disengage from the operating head and the guide elements will engage the tracks. If this occurs short of the raised position of the blind, the operator merely reengages the operating head withthe tabs and inches the blind into the desired raised position.

It is to be understood that the use of operating device 75 requires that the operator stand away from the blind being raised or lowered since handle 78 extends normal to the plane of the operating head. Also, when the lower end of the blind is some distance above floor level, engagement of operating head 77 with the drawbar of the blind requires that the head be disposed in a plane oblique to a vertical reference plane. Tabs 33, however, preferably are configured so that the head may be operatively engaged with the drawbar even though the plane of operating head 76 is not parallel to the plane of the blind.

There has Ebeen described above a simple device for raising and lowering a window blind to and from a position which is above the reach of a person operating the blind. While the invention has been described in lconjunction with specific apparatus, this has been by way of example only and is not to be considered as limiting the scope of this invention.

What is claimed is:

1. Apparatus for operating -a window blind having a drawbar at one end thereof including a pair of spaced operating ,handles which are movable toward each other to loosen the drawbar in drawbar guide means disposed adjacent the blind, the apparatus comprising a pair of substantially straight rigid rails having first and second ends, and means su-bstantially rigidly mounting the rails in fixed relation to one another so that the rails are disposed adjacent each other in substantially coplanar relation and so that the first ends of the rails are spaced apart laterally of the rails a distance a selected amount greater than the distance :between oppositely facingV surfaces of the drawbar operating handles with the rails converging toward each other to the second ends which are spaced apart a distance less than the distance between said oppositely facing surfaces and the rails are engageable with said handle surfaces.

2. Apparatus for operating a window blind or the like having a drawbar at one end thereof including a pair of spaced operating handles which are movable toward each other to loosen the drawbar in drawbar guide means disposed adjacent the blind, the apparatus comprising a yoke member having a base portion defining ends spaced apart a distance greater than the normal distance between oppositely facing surfaces of the drawbar operating handles, a rail member extending substantially rigidly from each end of the base portion and converging toward the other rail member at a location spaced from the base portion, the rail members at said location being spaced apart a distance less than the normal distance between said operating handle surfaces, and means connecting the rail members together at said location.

3. Apparatus according to claim 2 wherein the base portion is substantially straight and essentially rigid and the rail members converge linearly toward each other in a common plane from the base portion to the connecting means.

4. Apparatus according to claim 3 including an elongate handle connected to the base portion opposite the connecting means and extending from the base portion in the plane of the rail members- 5. Apparatus according to claim 3 including an elongate handle connected to the base portion opposite the connecting means and extending from the base portion normal to the plane of the rail members.

6. Apparatus according to claim 2 wherein the base portion defines a pair of legs which diverge from each other from a central portion of the base portion to spaced apart ends thereof disposed spatially between the connecting means and the central portion of the base portion.

7. Apparatus according to claim 6 wherein the rail members and the base portion legs are substantially straight and are of substantially equal length and including a rigid handle secured to said central portion.

8. Apparatus for operating a window blind or the like, the blind including a coiling device secured to an upper end of a vertically disposed elongate flexible sheet, a hollow rigid bar secured to the lower end of the sheet, the bar at eac'h end thereof carrying guide means adapted for engagement in a corresponding one of a pair of guide tracks disposed adjacent to the sheet, resilient means in the bar for biasing the guide means into engagement with the guide tracks to secure the bar in position relative to the guide tracks, and release means for the guide means including a pair of aligned spaced apart tabs which extend laterally from the bar and which are relatively movable toward each other against the bias of the resilient means to effect the disengagement of the guide means from the guide tracks, each tab having a surface exteriorly of the bar which opens toward the adjacent guide means, the apparatus for operating the blind comprising an operating member defining a pair of coplanar legs which converge linearly into connection with each other, the legs having opposing surfaces which are engageable with said tab surfaces, the legs remote from the connection thereof being spaced apart a distance sufficient to enable the legs to be engaged with said tab surfaces when the guide means are spaced from each other the maximum distance permitted by the distance transversely of the sheet between the guide tracks, and an elongate rigid handle connected to the operating member.

9. Apparatus for operating a window blind or the like, the blind including a coiling device secured to an upper end of a vertically disposed elongate flexible sheet, a hollow rigid bar secured to the lower end of the sheet, the bar at each end thereof carrying guide means adapted for engagement in a corresponding one of a pair of guide tracks disposed adjacent to the sheet, resilient means in the bar for biasing the guide means into engagement with the guide tracks to secure the `bar in position relative to the guide tracks, and release means for the guide means including a pair of aligned spaced apart tabs which extend laterally from the bar and which are relatively movable toward each other against the bias of the resilient means to effect the disengagement of the guide means from the guide tracks, each tab having a surface exteriorly of the bar which opens toward the adjacent guide means, the apparatus for operating the blind comprising an operating member defining two pairs of substantially coplanar diverging legs, the spaced apart ends of one pair of legs being connected to the spaced apart ends of the other pair of legs, each pair of legs having opposing surfaces which are engageable with said tab surfaces, the ends of the legs being spaced apart a distance sufcient to enable the legs to be engaged with said tab surfaces when the guide means are spaced from each other the maximum distance permitted by the distance transversely of the sheet between the guide tracks, and a rigid handle secured to the operating member.

10. In combination with a window blind or the like including a coiling device secured to an upper end of a vertically disposed elongate flexible sheet, a hollow rigid bar secured to the lower end of the sheet, the bar at each end thereof carrying guide means adapted for engagement -in a corresponding one of a pair of guide tracks disposed adjacent the sheet, resilient means in the bar for biasing the guide means into engagement with the guide tracks to secure the bar in position relative to the guide tracks, and release means for the guide means including a pair of aligned spaced apart tabs which extend laterally from the bar and which are relatively movable toward each other against the bias of the resilient means to effect the disengagement of the guide means from the guide tracks, each tab having a surface exteriorly of the bar which opens toward the adjacent guide means, apparatus for operating the blind comprising an operating member defining a pair of converging legs having Iopposing surfaces which are engageable with said tab surfaces, the legs remote from the point of closest convergence thereof being spaced apart a distance suiiicient to enable the legs to be engaged with said tab surfaces when the guide means are spaced from each other the maximum distance permitted by the distance between the guide tracks, the legs at the point of closest convergence thereof being spaced apart a distance no greater than the distance between the said tab surfaces when the guide means are moved the maximum distance relative to one another against the bias of the resilient means.

11. A method for raising a window blind to a height beyond the reach of a person, the blind including a spring biased coiling device secured to an upper end of a vertically disposed elongate ilexible sheet, a hollow rigid bar secured to the lower end of the sheet, the bar at each end thereof carrying guide means adapted for engagement in a corresponding one of a pair of guide tracks disposed adjacent the sheet, resilient means in the bar for biasing the guide means into engagement with the guide tracks to secure the bar in position relative to the guide tracks against the bias of the coiling device, and release means for the guide means including a pair of aligned spaced apart tabs which extend laterally from the bar and which are relatively movable toward each other against the bias of the resilient means to effect the disengagement of the guide means from the guide tracks, each tab having a surface exteriorly of the bar which opens toward the adjacent guide means, the method including the steps of (a) providing an operating device defining a pair -of legs which diverge downwardly from a point of closest convergence therebetween to spaced apart leg ends, the legs having opposing surfaces which are engageable with said tab surfaces, the legs at the spaced apart ends thereof being spaced apart a distance suflicient to enable the legs to be engaged with said tab surfaces when the guide means are spaced from each other the maximum distance permitted by the distance transversely of the sheet between the guide tracks, the legs at the point of closest convergence thereof being spaced apart a distance no greater than the distance between said tab surfaces when the guide means are moved the maximum distance relative to one another against the bias of the resilient means, and a rigid handle extending downwardly from the legs,

(b) engaging the tab surfaces between the legs of the -operating device,

(c) moving the operating device downwardly relative to the tabs with a force insucient to overcome the bias -of the coiling device but sufficient to impose on the tabs forces suicient to overcome the bias of the resilient means whereby the guide means are disengaged from the guide tracks so that the coiling device draws the bar upwardly,

(d) maintaining the operating device engaged with the tabs until the lower end of the sheet is disposed in a selected raised position,

(e) applying downward force on the operating device suicient to balance the bias of the coiling device so that upward movement of the bar is stopped at the selected raised position thereof, and

(f) moving the -operating device upwardly sharply relative to the tabs to disengage the operating device from the tabs so that the resilient means operate to engage the guide means in the guide tracks to maintain the bar at the selected raised position.

References Cited by the Examiner UNITED STATES PATENTS 528,501 10/1894 Bean 160-281 1,324,830 12/1919 Kryzanowsky 81-3.46 1,420,180 6/ 1922 Casmire 15-229.1 1,637,595 8/1927 Sturgis 15-147.0 2,063,583 12/1936 Christy 268--134 2,164,556 7/1939 Udstad 160-281 X 2,382,949 8/ 1945 McLaren 46-6 2,590,903 4/1952 Stretz 160-288 X 2,680,870 6/1954 Jones 15-229.1

FOREIGN PATENTS 170,979 10/ 1934 Switzerland.

HARRISON R. MOSELEY, Primary Examiner.

P. M. CAUN, Assistant Examiner.

Claims

1. APPARATUS FOR OPERATING A WINDOW BLIND HAVING A DRAWBAR AT ONE END THEREOF INCLUDING A PAIR OF SPACED OPERATING HANDLES WHICH ARE MOVABLE TOWARD EACH OTHER TO LOOSEN THE DRAWBAR IN DRAWBAR GUIDE MEANS DISPOSED ADJACENT THE BLIND, THE APPARATUS COMPRISING A PAIR OF SUBSTANTIALLY STRAIGHT RIGID RAILS HAVING FIRST AND SECOND ENDS, AND MEANS SUBSTANTIALLY RIGIDLY MOUNTING THE RAILS IN FIXED RELATION TO ONE ANOTHER SO THAT THE RAILS ARE DISPOSED ADJACENT EACH OTHER IN SUBSTANTIALLY COPLANAR RELATION AND SO THAT THE FIRST ENDS OF THE RAILS ARE SPACED APART LATERALLY OF THE RAILS A DISTANCE A SELECTED AMOUNT GREATER THAN THE DISTANCE BETWEEN OPPOSITELY FACING SURFACES OF THE DRAWBAR OPERATING HANDLES WITH THE RAILS CONVERGING TOWARD EACH OTHER TO THE SECOND ENDS WHICH ARE SPACED APART A DISTANCE LESS THAN THE DISTANCE BETWEEN SAID OPPOSITELY FACING SURFACES AND THE RAILS ARE ENGAGEABLE WITH SAID HANDLES SURFACES.