Releasable locking device

A releasable locking device is provided for securing a parked vehicle to an adjacent upright structure. The device includes a first means mounted on the upright structure and a second means mounted on the first means for vertical movement relative thereto between operative and inoperative mode positions. When in an operative mode, the second means is in a raised position and interlockingly engages a portion of the parked vehicle. A third means is provided which releasably retains the second means in an operative mode and prevents accidental movement of the second means from an operative mode position to a lower inoperative mode position. The first means includes guides for restricting movement of the second means to a substantially vertical path.

BACKGROUND OF THE INVENTION 
In order to reduce the risk of serious bodily injury and product damage and 
loss during loading and unloading of a parked vehicle, it is important 
that the vehicle be securely held in place against the loading dock. 
Heretofore securement of such parked vehicle has commonly been by way of 
blocks which are wedged against the front of the rear wheels. In other 
instances cables and hooks or chains have been employed which engage a 
portion of the rear of the vehicle and a stanchion or cleat provided on or 
adjacent to the loading dock. Also, locking devices have been utilized 
which require a source of electrical and/or hydraulic power to effect 
operation of the device. 
With regard to the use of blocks, they are ineffective where the roadway 
adjacent the loading dock is slippery because of rain, snow or ice. 
Furthermore, they frequently become lost or stolen and can accidently be 
moved out of a wedged position. 
Where cables and chains are employed, it requires careful manual 
manipulation when attaching to or detaching from the vehicle and loading 
dock and as a result in many instances such cables and chains are ignored 
completely. 
In devices requiring electro-hydraulic power sources, such devices are 
oftentimes expensive to install requiring substantial structural 
modifications to the dock. Furthermore, such devices are costly to 
manufacture and frequently are susceptible to malfunction. 
SUMMARY OF THE INVENTION 
Thus, it is an object of the invention to provide a device of the type 
described which is of simple, inexpensive construction and yet, is 
effective in securing a parked vehicle to an adjacent structure, such as a 
loading dock or the like. 
It is a further object to provide a device of the type described which 
doesn't require an electrical and/or hydraulic power source in order to 
operate. 
It is a still further object to provide a device of the type described 
which may be readily installed on an existing or new loading dock or the 
like and, if desired, may be utilized in combination with dock leveling 
equipment. 
It is a still further object to provide a device of the type described 
which is simple to operate and requires the expenditure of only a small 
amount of manual effort to manipulate same. 
It is a still further object to provide a vehicle locking device which is 
located so as not to interfere with the loading and unloading operation. 
It is a still further object to provide a locking device which is capable 
of being used with vehicles which vary in size and shape over a wide 
range. 
Further and additional objects will appear from the description, 
accompanying drawings and appended claims. 
In accordance with one embodiment of the invention, a releasable locking 
device is provided for securing a parked vehicle to an adjacent structure 
such as a loading dock or the like. In accordance with governmental safety 
regulations, most trucks are required to have mounted adjacent the rear 
end thereof a depending safety bar, commonly referred to as an "ICC bar". 
The purpose of the safety bar is to prevent a low profile vehicle from 
passing under the truck bed, when involved in a rear end collision. In the 
improved device, a first means is provided which is mounted on an upright 
surface of the loading dock adjacent the parked vehicle. Mounted on the 
first means is a second means which is relatively movable in a 
substantially vertical path between operative and inoperative mode 
positions. When the second means is raised to its operative mode position, 
it interlockingly engages the ICC bar of the parked vehicle and retains 
the latter in its parked location relative to the loading dock. The device 
is also provided with a third means which coacts with the first and second 
means and prevents accidental movement of the second means from the 
operative mode position to the inoperative mode position.

Referring now to the drawings and more particularly to FIG. 1, one form of 
the improved locking device 10 is shown mounted on the front vertical wall 
W of a conventional loading dock D. The wall W normally extends from an 
elevated horizontal platform surface P down to a roadway R on which a 
vehicle (e.g., a truck) is parked. 
Device 10 in the illustrated embodiment includes a first means such as a 
composite frame assembly 11 on which a second means such as a hook-like 
member 12 is mounted for vertical movement between an operative mode 
position I and an inoperative mode position II, shown in phantom lines in 
FIG. 1. When member 12 is in position I, it is elevated relative to the 
roadway R and interlockingly engages the ICC bar B of the parked vehicle, 
not shown, in a manner to be described more fully hereinafter. Frame 
assembly 11 includes a first member such as a plate-like base member 13 
which is anchored to the dock wall W by a plurality of bolts 19 or any 
other suitable means. Projecting outwardly from the exposed surface of 
member 13 is a pair of elongated, spaced, substantially parallel guides 
14, which may have an L-shaped cross-sectional configuration. The guides 
coact with member 13 to form oppositely disposed vertical channels. The 
guides 14 are welded or otherwise affixed to base member 13. 
Positioned between the guides 14 and in slidable face-to-face relation with 
respect to base member 13 is a second member such as an elongated 
plate-like element 15. As seen in FIGS. 2 and 3 the element 15 has a 
shorter vertical dimension than the guides 14 and the lower edge 15a 
thereof is engaged by a pair of matched heavy-duty biasing springs 16, 17. 
The lower end 16a, 17a of each spring is connected to a transverse bracket 
18 which is secured to the bottom of each guide 14. The upper end 16b, 17b 
of each spring is connected to a second bracket 20 affixed to and 
projecting outwardly from the lower edge 15a of element 15. The springs 
16, 17 are disposed within the guides and exert an upward biasing force on 
element 15 so that the latter normally assumes a rest position and engages 
a stop piece 21 secured to the upper end of each guide 14. The purpose of 
biasing element 15 to a raised rest position relative to base member 13 
will become apparent from the discussion to follow. 
Centrally disposed between the guides 14 and secured to element 15 is an 
elongated, substantially vertically disposed element such as ratchet 22. 
The ratchet and element 15 are slidable as a unit in a vertical plane 
relative to base member 13 when a depressing (downward) force, which 
exceeds the upward biasing force of springs 16, 17, is exerted on the 
ratchet 22 by the hook-like member 12. Such a depressing force occurs when 
the parked vehicle is being loaded and thus the springs absorb the load 
weight and prevent damage to the hook-like member 12 and/or frame assembly 
11. 
The hook-like member 12, as seen more clearly in FIG. 5, includes an 
elongated first section 23 which projects outwardly from the frame 
assembly 11. Extending angularly upwardly from the outer distal end of 
section 23 is a second section 24. The two sections 23, 24 are preferably 
integral with one another. The inner end 23a of the first section is 
secured by a shear pin 25 to a follower unit 26. The shear pin 25 permits 
sections 23, 24 to pull away from unit 26, only if an excessive pulling 
force is exerted on section 24 by the vehicle when the latter is 
accidentally attempted to be driven away from the loading dock while 
member 12 is in its operative mode position. Thus, the shear pin will 
prevent serious damage being inflicted on the device and loading dock by 
reason of such an occurrence. 
Unit 26 has a pair of spaced parallel lugs 26a which are disposed on 
opposite sides of the inner end 23a of the first section 23. The lugs are 
affixed to a cross piece 26b to which are secured a pair of laterally 
extending shafts 27, 28. The cross piece abuts the section end 23a. The 
shafts 27, 28 are in vertically spaced, parallel relation and the opposite 
ends of each shaft terminate within guides 14. Secured to the shaft ends 
are suitable rollers 29 which are sized so as to fit between the outer leg 
14a of each guide 14 and the outer surface of the marginal portion 15b of 
the plate-like elements 15 which is opposite the guide leg 14a, see FIG. 
4. Because of the relative size of the rollers 29, they coact with the 
adjacent guide legs 14a and the opposed marginal portions 15b of the 
locking element 15 and substantially retain the latter in sliding 
face-to-face relation with the base member 13. Because of the vertical 
spacing between shafts 27, 28, the hook-like member 12 is braced by the 
guides 14 so that the first section 23 will continuously remain in a 
substantial horizontal plane regardless of the relative position of the 
member 12 (i.e., in either the operative or inoperative position). 
Secured to and projecting upwardly from the unit cross piece 26b is a loop 
L, the function of which will become apparent from the discussion 
hereinafter. The loop is positioned between the guide legs 14a, as seen 
more clearly in FIG. 4. 
Pivotally connected at 30 to the lugs 26a of the follower unit 26 is a 
third means such as a pawl piece 31 which is adapted to coact with the 
serrations of ratchet 22 and prevent the hook-like member 12 from 
accidentally moving downwardly once the latter is disposed in a selected 
operative mode position, see FIG. 3. The pawl piece is preferably biased 
by a spring S so as to coact with the ratchet serrations. Pawl piece 31 in 
the illustration embodiment substantially subtends the follower unit 26 
and has a pair of spaced, substantially parallel, upwardly extending arms 
31a which overlie exposed portions of the lugs 26a and are pivotally 
connected thereto. Spanning the distancel between and connected to arms 
31a and subtending unit 26 is a jaw section 31b which is adapted to 
interlockingly engage the ratchet 22. 
Disposed in front of one guide 14 and extending laterally from one arm 31a 
of pawl piece 31 is a pintle 31c, see FIGS. 2-4. The pintle is spaced 
beneath the pivotal axis 30 of the pawl piece 31 and is adapted to be 
engaged by a manually actuated means such as release lever 32. The lever 
is disposed to the outside of one of the guides 14 and has the lower end 
32a thereof pivotal about a pin 33 which projects laterally from the 
bottom portion of the adjacent guide 14. The upper end 32b of the release 
lever projects upwardly a substantial amount, but not above the plane of 
the dock platform, so as to facilitate manual manipulation of the lever, 
see FIG. 1. When the lever is manually pivoted in a clockwise direction, 
as viewed in FIG. 3, the lever will engage pintle 31c causing the pawl 
piece 31 to pivot in a counter-clockwise direction about pivot axis 30 
thereby disengaging the jaw section 31b from the ratchet 22. Once the pawl 
piece is disengaged from the ratchet, the hook-like member 12 will fall by 
gravity to its inoperative mode position II, shown in phantom lines in 
FIG. 1. When member 12 is in the inoperative mode position, the upper end 
of the second section 24 thereof will be below the ICC bar B of the parked 
vehicle. Thus, it is important that member 12 be in its inoperative mode 
position when the vehicle is being maneuvered into or away from the parked 
position relative to the loading dock D. 
Once the vehicle has assumed the proper parked position with respect to the 
loading dock--that is to say the vehicle rear end is adjacent the loading 
dock front wall and engages the bumpers, not shown, disposed on either 
side of the device 10 and mounted on the dock wall W--the hook-like member 
12 is manually raised from its inoperative mode position II to the 
operative mode position I, see FIG. 1, wherein the member 12 
interlockingly engages the ICC bar B. That is to say, the ICC bar B is 
trapped between member section 24 and the guides 14. 
To facilitate the raising of member 12 to its operative mode position I, an 
implement 34 is provided which includes an elongated rod or shaft 34a 
having a first connecting means such as a hook 34b formed at its lower end 
and a cross handle 34c formed at its upper end. The rod 34a is of 
sufficient length so that a person standing on the dock platform P can 
conveniently manipulate the implement 34 to engage the hook 34b in a 
second connecting means such as a loop L provided on the follower unit 26, 
when the member 12 is in position II. Once the member 12 has reached its 
operative mode position I, the implement hook 34b is disengaged from loop 
L whereupon the member 12 will be retained in the desired operative mode 
position by the pawl piece jaw section 31b coacting with ratchet 22. While 
the lower end 34b of the implement 34 is shown as hook-shaped, it may be 
loop-shaped, whereupon a compatible hook would be substituted for the loop 
L on the follower unit 26. 
If desired, a cam piece 35, see FIG. 1, may be affixed to and extend 
upwardly from one of the stop pieces 21 mounted on the upper end of a 
guide 14. The cam piece 35 may be utilized where the device is used in 
combination with dock leveling equipment, not shown, and prevents the 
depending lip of such equipment abutting and becoming jammed against the 
tops of the guides when the deck of the dock leveling equipment is lowered 
into a horizontal or downwardly inclined position. The operation of dock 
leveling equipment is well known in the art and forms no part of the 
instant invention. The cam piece is an optional accessory and may be 
eliminated if desired. 
FIGS. 7-9 disclose a modified form 110 of the improved device and 
components thereof corresponding to similar components of device 10 are 
given like identifying numbers, but in a one hundred series. 
The frame assembly 111 in device 110 includes a base member 113 which has 
an H-beam configuration. The member 113 is fixedly secured in a vertical 
position by any suitable means (e.g., mounting plate K) on the exposed 
front wall W of a loading dock D or the like. Slidably mounted on the 
outer leg 113a of the member 113 is an elongated ratchet 122. The ratchet 
is mounted on the leg 113a by a plurality of guide bolts 113b which 
project from the leg 113a through longitudinally spaced, elongated slots 
122a formed along the vertical side portions of the ratchet. The ratchet 
122 is biased upwardly by a suitable heavy-duty spring, not shown, which 
engages the bottom edge of the ratchet in a manner similar to that 
previously described with respect to springs 16, 17. 
The outer leg 113a of base member 113 is in spaced, substantially parallel 
relation with an inner leg 113c and is connected thereto by a transversely 
extending web 113d. The web 113d and outer leg 113a coact to form a pair 
of guides 114 which are adapted to accommodate the rollers 129 attached to 
the inner end of the hook-like member 112. As noted in FIG. 7, the inner 
end 123a of a section of member 112 is connected by a shear pin 125 to a 
first pair of outwardly extending arms 126a formed on a follower unit 126. 
The unit is also provided with a second pair of spaced, substantially 
parallel rearwardly extending arms 126b which are disposed on opposite 
sides of member 113. To each arm 126b is connected a roller 129. 
Disposed in front of ratchet 122 and pivotally connected to unit arms 126a 
is a pawl piece 131. The configuration and location of the pawl piece 131 
may be like that of pawl piece 31 previously described. Disengaging the 
pawl piece 131 from the ratchet 122 may be accomplished by a release 
lever, not shown, similar to that described with respect to device 10. 
Likewise an implement 34 may be utilized to manually lift the hook-like 
member 112 to an operative mode position. Other means, such as a 
permanently connected chain, cable, or the like may be utilized in place 
of the implement 34 in order to raise the hook-like member 12, 112 to its 
operative mode position. Furthermore, other means besides a release lever 
32 may also be used to effect disengagement of the pawl piece 31, 131 from 
the ratchet 22, 122, when desired. 
Thus, an improved releasable locking device has been described which is of 
simple, inexpensive, and durable construction; may be readily installed on 
an existing or new loading dock construction; may be readily and 
effectively utilized with vehicles having ICC bars which vary in size and 
shape over a wide range; is capable of operating properly under extreme 
climatic conditions; and will not interefere with the loading and 
unloading of the vehicle.