Automatically collapsible trailer hitch for dump trucks

A collapsible trailer hitch to be used on a truck which has a pivoting platform for dumping, includes a Y-member attached to the chassis of the truck and a support member for the trailer tongue secured to a rotating bar journaled to the pivoting platform of the truck by mounting brackets. The support member is attached to the Y-member by means of connecting links which are pivoted at both ends. The hitch collapses and restores automatically upon pivoting of the platform.

Field of the Invention 
This invention relates to hitches and more particularly to an automatically 
collapsible trailer hitch for trucks which have rearwardly pivoting 
platforms, such as dump trucks. 
Description of the Prior Art 
It is often desirable to tow a trailer behind a dump truck. The trailer 
hitch for connection of the trailer to the truck must be connected to the 
frame of the truck. It is necessary that the hitch be so configured that 
when the dump bed is tilted for dumping (with the trailer unhitched) the 
hitch neither interferes therewith nor is moved into ground contact by the 
action of the bed. Since dump trucks are often required to discharge their 
loads while parked on irregular surfaces, it is desirable for the hitch to 
have as much ground clearance as possible when the dump bed is tilted in 
order to avoid damage thereto by contact with the ground or objects 
thereon. In addition, when the dump bed is in a non-tilted position, it is 
necessary for the hitch to be in a standard vertical position to receive 
the tongue of a trailer. 
Heretofore, collapsible trailer hitches have been provided for trucks 
including dump trucks. Most such hitches are collapsed by hand. Manual 
operation of the hitch requires the operator to leave the cab, and since 
the hitches are generally sturdily built, manual operation can be 
dangerous. In one prior self-collapsing type hitch, the hitch ball is in a 
relatively high position in the nontilted position, and the lowest 
position thereof is lower than the lowest portion of the dump bed in the 
tilted position, an unsatisfactory compromise in both cases. 
Summary and Objects of the Invention 
The hitch of the present invention collapses automatically upon the 
pivoting of the platform without manipulation of levers or other release 
mechanisms by a person outside the truck. Another feature involves the use 
of doubly pivoted connecting links between a stationary Y-member and a 
pivoting support member whereby the hitch rotates forwardly of the truck 
and upwardly upon collapsing. The short length of the connecting links 
limits the downward movement of portions of the hitch, thereby assuring 
greater freedom from damaging contact with objects when dump pivoting the 
platform. 
The principal objects of the present invention are: to provide a trailer 
hitch for dump trucks that collapses and restores automatically upon the 
pivoting of the bed of the truck; to provide such a hitch wherein the 
downward movement of parts thereof during tilting of the bed is limited to 
avoid damaging ground contact by parts of the hitch; and to provide an 
automatically collapsible trailer hitch for dump trucks that is of simple 
design, is economical to manufacture, easily installed, durable and well 
adapted for its intended purpose. 
Other objects and advantages of this invention will become apparent from 
the following description taken in connection with the accompanying 
drawings wherein are set forth by way of illustration and example certain 
embodiments of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in more detail: 
The reference numeral 1, FIG. 3, generally designates a conventional 
automotive truck with longitudinal structural chassis members 2 having 
attached thereto a platform pivoting bed 3 with longitudinal structural 
platform beams 4, said bed pivoting around pivot pin 5. Attached to the 
truck 1 is an automatically collapsible trailer hitch generally designated 
6 embodying the present invention. The hitch 6 includes a structural brace 
member 7 which is substantially Y-shaped and which is securely and rigidly 
attached to the chassis beams 2 such that the Y-member 7 is stationary 
with respect thereto. 
The brace member 7 may be a one-piece Y-shaped member; as illustrated, the 
brace 7 comprises two end-to-end Z-shaped arms 10 having rear leg portions 
11 and preferably is formed of angle iron having vertical portions or webs 
12 and horizontal portions or flanges 13. The arms 10 are initially bent 
downwardly and inwardly to a point where the distance between the two 
vertical portions 12 is slightly greater than the width of a telescoping 
tongue 15, at which point the vertical portions 12 angle rearwardly 
parallel with each other and with the structural member 2. 
A depending support member 16 is securely attached at an upper end to a 
sleeve 17 through which is placed a second sleeve or bar 18. The bar 18 is 
secured to spaced apart mounting brackets 19 which are attached 
respectively to the platform beams 4. Connecting links 22 are pivotally 
connected by a pin 23 at one end thereof to the legs 11 of Y-member 7 and 
are pivotally connected at the other end thereof by a pin 24 to two 
triangular flanges 25 which extend longitudinally forwardly from the 
support member 16. Secured between the two flanges 25 is a spacer sleeve 
26 which accepts the pin 24. 
At the other or lower end of the support member 16, a slot generally 
designated 28 is defined between the flanges 25, the slot 28 slidably 
receiving the tongue 15 (see FIG. 7). The top rearmost portion of the slot 
28 is defined by a bottom edge 29 of support member back or wall 30. The 
rearmost bottom portion of a slot 28 is defined by a roller assembly 32 
while the front bottom portion of slot 28 is defined by a bottom plate 33 
secured to the lower portions of the triangular flanges 25. The top of 
slot 28 is defined by a lower edge of 34 of a mud cover 35 that is secured 
between the triangular flanges 25, said mud cover 35 having an upper 
portion 36 parallel to bottom plate 33 and an angled portion 36' which 
includes the lower edge 34. The sides of slot 28 are defined by the 
triangular flanges 25. 
The roller assembly 32 is comprised of a pin 37 placed horizontally through 
two aligned apertures 38 that are positioned in the extreme bottom-most 
and rearmost portions respectively of the flanges 25. A sleeve 40 is 
positioned between the two flanges, and the pin 37 is received through the 
apertures 38 and the sleeve 40. The pin 37 is secured on one end by a head 
41 and on the other end by a fastener such as a nut 42. The tongue 15 
rests on the sleeve 40 which rotates on pin 37 as tongue 15 telescopes. 
The tongue 15 is in the general shape of a paddle (see FIG. 8) with a wide 
portion 50 being rearmost. A narrow portion 51 slides into and through 
slot 28. Between the wide portion 50 and the narrow portion 51 is a 
shoulder portion including angular shoulders 53 of approximately 45 
degrees which fit snugly against two similarly angled stops 54 when tongue 
15 is secured for towing. The wide portion 50 has two vertical bores or 
apertures 56 and 57 which are spaced apart and centered on the horizontal 
longitudinal axis thereof. A pintle ball 58 is secured in the rear 
aperture 56 for attaching a trailer (not shown) to the truck 1. Aperture 
57 is adapted to receive a pin 59 therein for securing the tongue 15 
against sliding with respect to the flanges 25. 
Pin 59 is pivotally attached at its top end to one end of a release handle 
60 which pivots in an aperture 66 in one triangular flange 25 through 
which it extends. Attached to the other end of release handle 60 is one 
end of a spring 67 which, at its other end, is attached to the sleeve 17 
in a position above the handle 60. In this manner, spring 67 biases the 
outside portion of handle 60 upwardly to urge the securing pin 59 
downwardly into the aperture 57 in the tongue 15. The pin 59 displaces 
vertically in a sleeve 70 which is used to guide pin 59 into aperture 47. 
The sleeve 70 is securely fastened to a horizontal plate 69 and is coaxial 
with an aperture 71, through which pin 59 passes. 
When the pin 59 is lifted out of the aperture 57, the tongue may be easily 
telescoped rearwardly and moved laterally to facilitate attachment to a 
trailer (not shown). Upon backing of the truck toward the trailer, the 
tongue locks in operational position by the pin 59 falling into its 
aperture 57. 
When dumping begins, the bed 3, along with the upper part of support member 
16, rotates downwardly through an arc about the pivoting pin 5. While this 
rotation is occurring, the connecting links 22 pivot at the one end around 
pivoting pin 23 and at the other end around pivoting pin 24. The support 
member 16 pivots rearwardly and upwardly around an axis defined by bar 18. 
As the bed 3 reaches its dumping position, the connecting links 22 have 
rotated to a position approximately opposite of their original position 
for towing and the support member 16 has rotated sufficiently such that 
the tongue 15 is now in a nearly vertical position, FIG. 4. The forward 
end of the tongue 15 fits in the void between the arms 10 and legs 11 of 
the Y-member 7. The relatively short length of the connecting links 22, in 
cooperation with lengths and position of the Y-member 7 and the support 
member 16, limits the downward movement of the parts of the hitch 6 during 
tilting of the bed 3 such that all parts of the hitch 6 are above the 
level of the lower rear edge 72 (FIG. 4) of the bed 3, as shown by line 
73, as the bed approaches the extreme tilted position. By this means, the 
hitch 6 is protected from contact with the ground or objects thereon. 
In an alternate embodiment, FIG. 9, the tongue 15' does not telescope but 
rather is securely attached, as by welding, to appropriate surfaces of the 
support member 16. The automatically collapsible hitch feature functions 
as in the first described embodiment. 
It is to be understood that while certain forms of this invention have been 
illustrated and described, it is not to be limited thereto except insofar 
as such limitations are included in the following claims.