NZ242989A - Hitching pin for coupling trailer to tractor - Google Patents

Description

24 2 9 8 9 NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION IMPROVEMENTS IN AND/OR RELATING TO TOWING HITCH I, GORDON CHARLES McGUINNESS, a New Zealand citizen of Hastings Road, No. 15, Hawera, New Zealand do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a hitching pin particularly though not solely for coupling a trailer to a tractor.

Hitching pins are used to secure trailers or trailing implements to linkage eyes on the rear of prime movers such as tractors on farms. Under the rugged conditions encountered in use hitching pins can work themselves loose if they simply rely on gravity to keep them in place. It is desirable to have hitching pins with a retaining mechanism able to keep the hitching pin positively in place during use while also being able to be released quickly when the trailer or trailing implement is to be disconnected.

It is an object of this invention to go some way towards achieving these desiderata or at least to provide the public with a useful choice.

In a first aspect the present invention may broadly be said to consist in a hitching pin comprising: a stop means mounted at or near a first end of said shaft, a retaining means pivotally connected to said shaft and spaced apart from said stop means, said retaining means being moveable between a locked position wherein said retaining means extends substantially perpendicular to said shaft and an unlocked position wherein said retaining means is substantially axially aligned along the length of said shaft, and holding means to hold said retaining means in said locked position until sufficient force is applied to said retaining means to overcome the resistance offered by said holding means.

In one alternative construction said stop means comprises a second said retaining Preferably said retaining means comprises a lug pivotally moveable into and o , a recess at or near a second end of said shaft. ■■,, a shaft, means, 3 24 2 9 89 Preferably said lug includes at least two rests which in use are adapted to engage with said holding means and hold said lug in said locked and unlocked positions respectively.

Preferably said lug includes three rests adapted in use to individually engage with said holding means to hold said lug in one of said locked and unlocked positions and in an intermediate position intermediate said locked and unlocked positions.

Preferably said holding means comprises a pawl mounted in said shaft and biassing i adapted ic bios said pawl into engagement with said retaining means wherein said pawl holds said retaining means in a selected position.

Preferably said biassing means is a spring.

Preferably said stop means comprises a head having a diameter greater than the width of said shaft.

Preferably said stop means forms an integral part of said shaft.

Preferably said hitching pin further comprises auxiliary biassing means to prevent said retaining means from moving from said closed position to said open position in use until sufficient force is applied to said auxiliary biassing means to overcome the resistance offered by said auxiliary biassing means.

Preferably said auxiliary biassing means comprises a coil spring on said shaft adjacent said stop means which in use biases said stop means axially away from a hitching bracket into which said hitching pin has been inserted to thereby retain said holding means in said locked position against a second hitching bracket.

In a further aspect the invention may broadly be said to consist in a hitching pin when constructed arranged and operable substantially as herein described and as illustrated by the accompanying drawings. -4- 24 2 9 8 9 The invention consists in the foregoing and also envisages constructions of which the following gives examples.

Two preferred forms of the invention will now be described with reference to the drawings accompanying the provisional specification in which: Figures 1A to 1C Figures 2A to 2D Figure 3 Figures 4A and 4B are side views partly broken away of a hitching pin in accordance with a preferred embodiment of the invention showing the retaining means in an unlocked position (A), a locked position (B) and an intermediate position (C). are views of individual components of the retaining means and holding means of the hitching pin of figures 1A to 1C. is a side elevation partly in cross-section of a second embodiment of the invention shown in place in a hitching bracket. are schematic views of the hitching pin of Figures 1A to 1C showing the operation of the hitching pin in coupling a tow bar to a prime mover. Figure 4A shows the pin in the unlocked position and figure 4B shows the pin in the locked position.

A third form of the invention will be described with reference to the accompanying drawing in which: Figure 3A is a side elevation, partly broken away of a third embodiment of the invention shown in place in a hitching bracket.

Description of First Embodiment Referring to the drawings a hitching pin 8 in accordance with a preferred embodiment of the invention comprises a shaft 10 having a recess portion 12 which - 24 2 9 8 9 forms a gap between two parallel sides of the shaft (the arrangement being similar to the tines on a tuning fork) and an axial bore 14 at one end 16 and a stop means 18 at the opposite end 20. Shaft 10 is preferably formed from a rod of a suitable steel alloy or the like but may be formed from any suitable material such as a reinforced plastics material of suitable strength and rigidity.

A retaining means is provided at or near end 16 of shaft 10. In the preferred embodiment the retaining means comprises a lug 22 which is preferably formed from a suitable steel alloy or the like but may be of any other suitable material. Lug 22 comprises an elongated strip of material having a width which is substantially the same as the width of shaft 10 and a thickness less than the width of the gap formed between the two parallel sides of shaft 10 by recess portion 12, and includes a body portion 26 and a handle portion 28 able to be manually manipulated in use. Lug 22 is pivotally connected to shaft 10 so that body portion 26 is moveable within recess portion 12 and handle portion 28 extends beyond the end of shaft 10. A pivot pin 30 which is preferably a split pin (figure 2B) is provided which passes through shaft 10 and the body portion 26 of the lug 22. Body portion 26 further includes rests 32, 34 and 36 to hold said lug 22 in use in an unlocked, intermediate or fully locked position, and a shoulder portion 44 extending outwardly beyond rest 32. Holding means 46 are provided which in use are adapted to engage with rests 32, 34, 36 and hold the lug in a selected unlocked, locked or intermediate position. Holding means 46 comprises biassing means 48 which is preferably a coil spring and a pawl 50 arranged in bore 14 so that pawl 50 is in use engageabk- with a selected one of rests 32, 34, 36.

Stop means 18 preferably comprises a head 56 which is preferably an integral part of shaft 10. Head 56 is of wider diameter than shaft 10 and, thus, a shoulder 58 is formed between the shaft 10 and the underside of head 56 to prevent the head from passing through the eye of a hitching bracket.

In an alterative embodiment stop means 18 is a second retaining means which is preferably of the same or similar construction to the retaining means at the other oa ? 9 end of shaft 10 described above. In this embodiment holding means 4& are provided at each end of shaft 10.

Description of Second Embodiment A second embodiment of the invention is illustrated in figure 3. In this embodiment a hitching bracket comprising a cross-member (not shown) joins arms 70, 72 through which are provided apertures or eyes 66, 68. Hitching pin 8 passes through eyes 66 and 68. Biassing means 64 which is preferably a coil spring is arranged on shaft 10 between head 56 and arm 70. A handle 62 is provided to enable biassing means 64 to be compressed.

Description of Third Embodiment The third embodiment in figure 3A is similar to the second embodiment shown in figure 3 in that it includes a biasing means 64 in the form of a coil spring on shaft 10 resting against shoulder 58 of head 56. Where it differs is that lug 22 is freely pivotal about pin 30 without any pawl and spring in recess 12 in shaft 10 or corresponding rests in lug 22. Rather lug 22 has a sloped edge 24 and recess 12 of shaft 10 has a corresponding sloped bottom 25 as shown through the cut away portion of shaft 10. The other features are the same as in figure 3. The hole in lug 22 through which pin 30 passes is off centre. The heavier end is at handle 28 so that when the hitching pin is held vertically handle 28 falls downwardly and edge 24 of lug 22 rests against bottom 25 of recess 12.

Operation of First Embodiment In use, as depicted in figures 4A and 4B, the hitching pin of the rirst embodiment of the invention is used to couple a trailer or implement tow bar with a prime mover hitching bracket. Bracket 60 consists of two parallel arms 70, 72 each arm having a hole or eye 66, 68 near one end through which the hitching pin 8 can pass. The trailer or implement has a tow bar 84 ending in an eye 78 in which is seated a rubber bearing 80. The diameter of the opening through bearing 80 is sufficient to allow shaft 10 to slide easily into place. .7- 74 2 9 8 9 .wn •' A hitching pin 8 having its retaining means 16 in the unlocked position depicted in figure 1A (that is, having pawl 50 engaged in notch 32) is passed through arms 70, 72 and through bearing 80 until shoulders 58 of head 56 meets arm 70.

Handle portion 28 of lug 22 is manually manipulated from the first position (see figure 1A) compressing spring 48 to allow pawl 50 to move out of rest 32. Lug 22 is pivoted within recess 12 from the unlocked position shown in figure 1A to the locked position shown in figures IB and 4B. When the pawl 50 is beneath rest 36 the spring 48 urges the pawl 50 into the rest, thus, holding the lug 22 in the closed position (figure IB).

Figure 1C depicts the lug 22 in an intermediate position where pawl 50 engages with rest 34. This is a safety mechanism which allows the hitching pin to remain locked in position if in the course of travel lug 22 should catch on an obstruction and release pawl 50 from rest 36. In such a case it will engage the next rest 34 leaving lug 22 in a secondary locked position. When shoulder portion 44 comes into contact with arm 72 it trips lug 22 back into the locked position.

Operation of Second Embodiment The second embodiment of the invention depicted in figure 3 is a further safety feature to prevent accidental release of a hitching pin where it is possible the lug 22 may be tripped by coming into contact with the ground. Spring 64 urges the head 56 of hitching pin 8 upwardly when in the locked position. This also urges the upper faces of lug 22 against the bottom of arm 70. If lug 22 should catch on an obstruction the force of the obstniction must overcome the biassing forces of both springs 64 and 48 before lug 22 will pivot at all. Then the intermediate rest 34 must be passed by pawl 50 before the hitch pin is in a fully unlocked position.

Operation of Third Embodiment In operation when the longitudinal axis through apertures 68 and 66 lies in a vertical plane hitching pin 8 is aligned with the holes and lowered through them. Lug 22, because of its eccentric pivot point, is aligned with arm 28 falling 24 2 9 89 downwardly and passes easily through. When spring 64 contacts the upper surface of bracket arm 70 extra pressure is exerted on handle 62 and spring 64 is compressed until the uppermost corner of edge 24 clears the bottom of bracket arm 72. Handle 28 of lug 22 is then pivoted to the horizontal position shown in figure 3A and the handle 62 is released. The compression in spring 64 then holds the hitching pin 8 in the position illustrated.

The hitching pin of figure 3A may also be used where bracket arms 70 and 72 are positioned so that a longitudinal axis through holes 68 and 66 lies in a horizontal plane. In such a case pin 8 is oriented so that the left side (see in figure 3A) is up so that finger 28 is aligned with shaft 10 because edge 24 rests against bottom 25. Pin 8 can then be inserted through holes 68 and 66. As in the vertical alignment spring 64 is compressed until the lower corner of sloped edge 24 clears the outer face of arm 66. Handle 62 is then rotated through 180° and pin 28 falls into the position shown in figure 3A. Pressure on handle 62 is then released to lock the lug in the position shown.

Thus, it can be seen that the invention has the advantages that it provides a towing hitch which can be easily released by manual manipulation but does not release when an implement or trailer is being towed by a prime mover.

The invention has been described in relation to a hitching pin for hitching an implement or trailer to a prime mover such as a farm tractor. However, it will be apparent to those skilled in the art to which this invention relates that the invention may be used for any such pin.

To those skilled in the art to which this invention relates many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined above. The disclosures and descriptions herein are purely illustrative and are not intended in any sense to be limiting.

Claims (12)

WHAT WE CLAIM IS:

1. A hitching pin comprising: a shaft, a stop means mounted at or near a first end of said shaft, a retaining means pivotally connected to said shaft and spaced apart from said stop means, said retaining means being moveable between a locked position wherein said retaining means extends substantially perpendicular to said shaft and an unlocked position wherein said retaining means is substantially axially aligned along the length of said shaft, and holding means to hold said retaining means in said locked position until sufficient force is applied to said retaining means to overcome the resistance offered by said holding means.

2. The hitching pin as claimed in claim 1 wherein said stop means comprises a second said retaining means.

3. The hitching pin as claimed in claim 1 or 2 wherein said retaining means comprises a lug pivotally moveable into and out of a recess at or near a second end of said shaft.

4. The hitching pin as claimed in claim 3 wherein said lug includes at least two rests which in use are adapted to engage with said holding means and hold said lug in said locked and unlocked positions respectively.

5. The hitching pin according to claim 4 wherein said lug includes three rests adapted in use to individually engage with said holding means to hold said lug in one of said locked and unlocked positions and in an intermediate position intermediate said locked and unlocked positions.

6. The hitching pin according to any one of the preceding claims wherein said holding means comprises a pawl mounted in said shaft and biassing means adapted - 10- to bias said pawl into engagement with said retaining means wjw^m ^d q holds said retaining means in a selected position. ■

7. The hitching pin according to claim 6 wherein said biassing means is a coil spring.

8. The hitching means according to claim 1 and any one of claims 3 to 7 when not dependent from claim 2 wherein said stop means comprises a head having a diameter greater than the width of said shaft.

9. The hitching means according to claim 8 wherein said stop means forms an integral part of said shaft.

10. The hitching means according to any one of the preceding claims further comprising auxiliary biassing means to prevent said retaining means from moving from said closed position to said open position in use until sufficient force is applied to said auxiliary biassing means to overcome the resistance offered by said auxiliary biassing means.

11. The hitching means according to claim 10 wherein said auxiliary biassing means comprises a coil spring on said shaft adjacent said stop means which in use biases said stop means axially away from a hitching bracket into which said hitching pin has been inserted to thereby retain said holding means in said locked position against a second hitching bracket.

12. A hitching pin when constructed, arranged and operable substantially as herein described and as illustrated by the drawings accompanying the provisional specification and by the accompanying drawing. Qodon UO'ks f7%uXr^r Wf Ir/uthorlsod ^ A. J. PAR,