CA2292347C - Folding blade - Google Patents

Abstract

A mid-chassis, underbody plow or scrapper blade is mounted under a vehicle chassis to be folded upwardly for storage when not in use. The blade is also mounted to permit the outer ends of the blade to move vertically. Pneumatic pressure actuators mounted on either side of the center line of the vehicle apply pressure through blade support means in the form of pivot arms to the respective ends of the blade to control the scrapping action. The blade support means swings upwardly to achieve a two-stage storage which increases the elevation of the blade when folded.

Description

Title: FOLDING BLADE

Field of the Invention This invention relates to plowing equipment. More particularly, it relates to a support system for a mid-chassis, underbody plow or scrapper system that controls the deployment of a blade and its storage beneath the vehicle between deployment. The invention is suited especially for installation on the underbody of trucks for use as snow plows.
Backaround to the Invention Mid-chassis or underbody plows and scrappers are well known vis. U.S. Patent Nos. 4,031,966; 4,337,832. Such plows have been designed to fold upwardly for storage, c.f.
U.S. Patent No. 4,031,966 depicting rearward folding.

In designing an underbody plow or scrapper with a folding blade it is desirable to provide adjustability to raise or lower the blade, to tilt the blade, raising its outer ends up and down about a horizontal axis that is generally pointed outwardly from the blade surface. Blades are often required to be angled to the left and right about a vertical axis. It is also desirable when the plow blade is light, to provide a supplementary force-control mechanism that will apply a downward force to the plow blade to maintain it in = CA 02292347 1999-12-17 contact with the surface being plowed with the appropriate level of pressure. It would be highly desirable to combine these features with an under body plow having a storage feature that would permit it to be raised above the road surface when not deployed.

These features of control should ideally be achievable, in whole or in part, at minimal cost and with a minimal addition of weight to the vehicle.

It is therefore an object of the invention to provide an underbody blade support system that has various combinations of the above features combined with simplicity and low cost.

The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.

Summary of the Invention The invention employs an underbody plow blade or scrapper with a mold board and two outer ends, (hereafter referred to generally as a scrapper blade) which is mounted to extend generally transversely beneath the chassis of a vehicle. This scrapper blade is positioned between the forward and rearward sets of wheels on the vehicle and may be angled to be oriented to the left or right while still extending generally transversely beneath the vehicle.

A feature of the invention is that the blade may be folded, preferably forwardly, to raise it above the road surface in a stored position. In its folded orientation, the mold board of the plow is upwardly directed. Preferably, rotation of the mold board from its deployed position is effected about a hinge line that is rearwardly of and intermediate the top and bottom edges of the mold board. The top edge may, in being folded, retire from a first deployed stop means to a second folded stop means against which the top edge may bear.

Preferably, the blade-folding system of the invention is carried by an elevating support to cause the folded blade to retire upwardly. Thus, in a preferred arrangement, the blade may be carried at the end of a pivot arm assembly in the form of two trailing arms that are mounted to the chassis so as to extend downwardly from a forwardly-mounted hinge mount. The upper edge of the mold board may nest in a recess formed in the pivot arms. The pivot arm assembly hinge mount allows rotation of the pivot arm assembly about an axis that is also generally transverse to the direction of motion of the vehicle. Other means of supporting and elevating the blade are, however, permissible, in order to provide this two-stage storage effect.

The scrapper blade is preferably tiltable in the sense that one of its two outer ends may be elevated vertically with respect to the other end. This may be effected in one preferred manner by providing a rotatable coupling between the vehicle chassis, e.g. within the pivot arm assembly, and the scrapper blade that allows the scrapper blade to rotate about a generally horizontal axis extending forwardly and rearwardly beneath the vehicle. Other means of providing for such freedom of motion may also be employed, including independently hinged pivot arms.

Preferably the scrapper blade with its scrapping edge is positioned against a road surface by two pressure actuators respectively located between the blade and the vehicle chassis at spaced locations on either side of the centerline of the vehicle. These pressure actuators may be in the form of pneumatic bladders to apply a resilient downward pressure on the scrapper blade through the elevating support.
In the case of the use of a pivot arm assembly, the pressure actuators may be positioned between the chassis and the pivot arms.

5 As an optional feature, by independent control of the pressure actuators, differing vertical forces may be applied to the respective outer ends of the scrapper blade.
Consequently a greater amount of contact pressure may be maintained between the scrapper blade and the surface being scrapped at one outer end of the blade than at the other outer end. This greatly facilitates the removal of snow, ice or other debris from a road surface when the level of material to be removed is higher on one side of the vehicle than on the other side of the vehicle.

The preferred type of pressure activator is a pneumatic bladder of the type generally employed in air springs. Their role is to press the blade edge resiliently against the road surface, lifting-off ice, snow and debris from that surface. Such devices are not only relatively inexpensive, but also provide a "spring" resilience that allows the scrapper to move vertically to accommodate vertical variation in the surface being scrapped.

To complement the folding action by which the scrapper blade is raised for storage above the road surface, the elevating support, e.g. the pivot arm assembly, may be provided with a blade folding actuator coupled between the pivot arm assembly and the vehicle chassis to serve as well as a lifting actuator. Action as a lifting actuator may be achieved in conjunction with the folding of the blade by providing a lifting link, such as a chain, that extends between a folding portion of the blade and the vehicle chassis.

The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow.

Summary of the Fiaures Figure 1 is a side view of a prior art vehicle carrying a mid-chassis, underbody plow blade carried by a pivot arm assembly that serves as one aspect of a preferred variant of the invention when combined with a folding plow blade;

Figure 2 is a perspective view of a cut-away portion of the vehicle of Figure 1 taken from the left rear quarter with the pneumatic actuators omitted for clarity;

Figure 3 is the view of Figure 2 with pneumatic actuators depicted in position;

Figure 4 is a rear-end view of the vehicle of Figure 1 with the pivot arm assembly lowered;

Figure 4a is a rearward view of the vehicle of Figure 1 with the pivot arm assembly raised;

Figure 4b shows a rearward face view of the tilting plate assembly;

Figure 5 depicts the vehicle of Figure 2 with the air distribution and control system in place;

Figure 6 is a plan view of the folding blade configuration of the invention;

Figures 7a and 7b are side views of the blade of Figure 6 respectively deployed and folded for storage;
Figures 8a and 8b are side views along the blade respectively when deployed and when folded;

Figure 9 is a detailed view of Figure 8a showing the stored view of the blade of Figure 8b in ghost outline;
Figure 10 is a plan view of a folding blade configuration of the invention having separately hinged pivot arms to provide the pivot arm assembly.

Description of the Preferred Embodiment In Figure 1 a vehicle 1 having a chassis 2, forward wheels 3 and rearward wheels 4 carries between these sets of wheels 3,4 a scrapper blade or plow blade 5. While reference hereafter will be made to a "blade" 5 this language is intended to encompass any form of scrapper blade, including rake and chisel-like constructions.

Figure 1 is prior art. However, Figure 1 will be described in detail because it provides a synergistic environment for the folding blade feature of the invention.

The blade 5 is carried by a pivot arm assembly 6 having two pivot arms 6a, 6b that trail below the chassis 2 from pivot arm hinges 7 coupled to the chassis 2 at the forward end of each pivot arm 6a,6b. The hinges pivot arm 7 permit rotation of the pivot arms 6a,6b about an axis that is transverse to the direction of the vehicle 1. The pivot arms 6a,6b may be mounted to rotate independently (not shown) to permit the blade 5 to tilt. An alternate, preferred tilting arrangement is detailed further, below.

Positioned between the chassis 2 and blade 5 are two pneumatic bellows 9a, 9b respectively mounted on opposite sides of the centerline 10 of the vehicle 1. Based on pneumatic springs, these bellows 9a,9b act as controllable pressure actuators which are able, in a preferred arrangement, to apply independently differing pressures to the outer ends lla,llb of the blade 5.

A preferred structure for allowing the blades to tilt, i.e. to effect vertical displacement of the outer ends lla, llb of the blade 5, is shown in Figures 2-5. For simplicity of depiction, the blade folding feature of the invention is not shown in Figures 2-5. Tilting is effected by the presence of a rotary coupling 12 incorporated into a pair of transverse tilting plates 13a,13b. A first one of these plates 13a extends between the pivot arms 6a,6b; the second of these plates 13b extends between two blade support arms 14a, 14b that connect to the blade 5. A central pin 15 coupled to the two tilting plates 13a,13b permits rotation of the blade support arms 14a, 14b and blade 5 about a horizontal axis that is generally aligned with the direction of travel 10 of the vehicle 1.

The plates 13a, 13b preferably are positioned closely together so that their outer ends may brush together to absorb dislocating forces that tend to swivel the blade 5 to the left or right. As well, welded pins or bolts 45 may extend from the ends of one plate 13a to carry containment plates 46 that contain or "trap" the outer ends of the second plate 13b (or in the reverse arrangement extending from the second plate 13b to contain the first plate 13a). This is to absorb tensional forces while permitting rotation between the plates 13a,13b. Specific bearing surfaces may be provided with respect to each of the plates 13a,13b to absorb the brushing contact action.

In Figure 2 the alternate position of the tilted blade 5 is shown in ghost outline 5a with one end llb raised and the other end lla lowered.

In Figure 3 the pneumatic bellows 9a, 9b omitted from Figure 2 for clarity are shown positioned to apply force between the chassis 2 and the blade 5 through the respective blade support arms 14a, 14b. These pressure actuators 9a,9b 5 are spaced apart and positioned to apply similar or differing pressures at the outer ends of the blade 5 in pressing the blade downward onto a road surface 36.

The pivot arm assembly 6 may be raised by chains 16 descending from a frame 17 that includes a transverse bar 18 10 that overlies a further air spring lifting bellows 19 positioned on the chassis 2. The pivot arms 6a, 6b according to this lifting arrangement are coupled to the chains 16 at locations between their ends to provide the action of a third class lever.

To raise the blade 5, the pressure in the pressure actuator bellows 9a,9b is released (through valves 24) and that in the lifting bellows 19 is increased. The force of the lifting bellows 19 is transmitted through the frame 17 and chains 16 to the pivot arm assembly 6 raising the blade 5 upwardly off of the surface being scrapped. This operation may be seen in Figures 4 and 4a wherein the pivot arm assembly 6 is respectively lowered and raised. An alternate lifting arrangement may be employed with the folding-blade configuration, described further herein.

The control system for the blade support is depicted in Figure 5. A source of pressurized air 21, depicted as an air tank, provides air to a pressure distribution box 22.
Pressurized air is directed from this box 22 to the lifting bellows 19 and pressure actuator bellows 9a,9b, through air lines 23 in response to manually set input signals, preferably originating remotely from within the vehicle cab. Exhaust valves 24, responding in cooperation with the operation of the pressure distribution box 22, exhaust or vent air from bellows 9a,9b,19 when they are to be depressurized, e.g. venting lifting bellows 19 when pressure actuators 9a,9b are pressurized. Manometers 25 display the pressure conditions within the system.

Through the pressure distribution box 22, controlled levels of pressure may preferably be developed independently in each of the bellows 9a,9b controlling the scrapping effect of the blade 5 on the road surface. A different pressure need not necessarily be applied through the bellows 9a,9b; but such option is available.

The folding-blade feature of the invention is shown in plan view in Figure 6. To assist in perceiving the positioning of the plow components, the wheels 3, 4 are depicted at disembodied locations in Figures 6, 7a and 7b.

In Figures 6, 7a and 7b the tilting plates 13a, 13b have been shifted forwardly under the vehicle, to a location proximate to the pivot arm hinges 7. In this arrangement, the pivot arms 6a,6b are greatly shortened and the blade support arms 14a,14b are greatly lengthened. The freedom of action provided to permit the blade 5 to tilt is, however, the same in principle as described previously. For the further discussion following herein, the blade support arms 14a,14b will be addressed as forming part of the pivot arm assembly 6.

In Figure 6 the blade 5 is fixed transversely to the chassis 2 at an angle, e.g. 28 degrees, out of alignment with the vehicle. The blade 5 is carried by the two support arms 14a,14b and respective air bladders 49a,49b are positioned to develop a downward thrust upon such arms 14a,14b.

The blade 5 has its own blade hinge axis 30 and is positioned by a cylinderical actuator 31 mounted on a transverse bar portion 32 of the pivot arm assembly 6. A

linearly actuated shaft 33 extends from the actuator 31 to join with the blade 31 at a blade-actuator hinge 34. The blade hinge axis 30 is behind the blade 5, positioned intermediate of the upper edge 32 and the scrapping edge 37 of the blade 5.

The dual folding action of the blade 5 is shown in Figures 7a and 7b which respectively depict blade 5 as deployed and folded upwardly for storage. It will be noticed that, as a preferred feature, the support arms 14a,14b are also swung upwardly from their deployed position, in Figure 7a, to their storage position, in Figure 7b, when the blade 5 is folded upwardly with mold board 5a of the blade directed upwardly. The upward swing raises the arcuate portion 39 of the arms 14a, 14b closing-up the difference 50,50a.

In Figures 8a and 8b, details of the blade-folding action are shown in side view, looking endwise along the blade 5. In Figure 8a the blade 5 is deployed with its scraping edge 35 positioned on a road surface 36 and its upper edge 37 bearing against a blade-deployed stop surface 38 positioned on arcuate portion 39 of the support arms 14a, 15b of the pivot arm assembly 6. The shaft 33 of the actuator 31 is fully extended, having carried the upper edge 37 of the blade 5 to the stop surface 38. Thus the stop surface 38 absorbs the obstructions encountered by the blade 5 on the road surface 36, rather than the actuator 31.

In Figure 8b the blade 5 is shown as folded, the upper edge 37 having passed rearwardly beneath arcuate portions 39 of the support arms 14a,14b upon retraction of the shaft 33 (not visible in Figure 8b) to rest against folded-blade stop surface 38a. Rotating about blade hinge axis 30, the lower, scraping edge 35 is elevated above the road surface 36 to present the mold board 5a of the blade upwardly once the upper edge 37 reaches the folded-blade stop surface 38a.

To achieve a double-action lifting effect with a maximum economy of components, a linkage in the form of a chain 40 extending between the blade 5 and chassis 2 is tightened by the retraction of shaft 33 and the forward rotational advance of the lower half of the blade to which it is connected. The action draws the support arms 14a,14b upwardly towards the chassis 2. The corner 41 formed on the transverse bar portion 32 of the pivot arm assembly 6 may be strengthened and shaped to permit the chain 40 to slide around this corner 41 during this lifting action. A stopping arm 50 connected to the transverse bar 32 rises until it abuts a chassis rest 51, limiting further upward travel of the blade 5 pivot arm assembly 6.

As shaft 33 is not in an intersecting alignment with hinge axis 30, the linear actuator 31 is mounted to the transverse bar portion 32 by a swivelling support means that rotates about actuator axis 42 (indicated as to its location in Figures 8a, 8b). Thus the actuator 31 has differing orientations in Figures 8a and 8b. The difference in these orientations are shown in Figure 9 wherein a ghost outline 31a shows the actuator 31 when the blade 5 is in its stored position.

Figures 1 through 5 depict an environment in which the folding blade 5 of Figures 6 through 9 may be installed.
In Figure 10 the pivot arm assembly 6 is shown as being attached to the chassis 2 by independent hinge joints 53.

These joints 53, optionally of the Torrington type, allow the pivot arms 14a, 14b to rotate independently. This dispenses with the need for tilting plates 13a, 13b.

As shown in Figure 10, a side of the stopping arm 50 may bear against a portion of the chassis 2 to limit sideways 5 displacement of the blade 5 and pivot arms 14a, 14b.

The combined effect of both folding the blade 5 to direct its mold board 5a upwardly and swinging the support arms 14a,14b upwardly allows the blade 5 to be stored with maximum elevation under the chassis 2. This is highly 10 desirable as it allows the vehicle to travel at high speeds over uneven road surfaces 36 with reduced risk that the stored blade 5 will contact a protruding portion of the road surface 36 or strike an object lying on the road.

The use of air-activated pressure actuators 9a,9b 15 renders the blade support of the invention light in weight and less costly than hydraulic systems. The light weight of the blade 5 and pivot arm assembly 6 is supplemented by pressure applied through the bellows 9a,9b, 49a,49b which respond resiliently to variations in the height of the road surface 36. The rotary coupling 12 of the tilting plates 13a,13b in the pivot arm assembly 6, or the use of flexible Torrington-type joints 53, allows the scrapper blade 5 to adjust to the contour of the road surface 36 in the preferred variants of the invention. The angled orientation of the blade 5 allows debris to be transferred to the left or right side of the vehicles. Individually and collectively an improved means is provided for clearing a road surface.

Conclusion The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow.

These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.

Claims (13)

1. A plow assembly for mounting on a vehicle for grading and snow removal, said vehicle having forward and rearward ends and forward and rearward wheels, comprising:

1) chassis mounting means;

2) a blade mounted in a generally transverse orientation beneath the chassis between the forward and rearward wheels, said blade having a forward mold board face surface, two outer ends, a lower scrapping edge and an upper edge;

3) blade support means carried by the chassis mounting means and extending to the blade to position the blade beneath the chassis; and

4) a blade-folding hinge with a folding hinge axis extending transversely with the blade as part of the blade support means whereby the blade may be folded by swinging the scrapping edge upwardly and forwardly about the folding hinge axis for storage beneath the chassis of the vehicle with the mold board face surface upwardly directed.

2. A vehicle as in claim 1 wherein said blade support means comprises rotational means to allow the blade to tilt, whereby one of the outer ends of the blade may be elevated with respect to the other.

3. A vehicle as in claim 1 wherein said blade support means comprises a pivot arm assembly mounted at its forward end to said chassis mounting means for rotation about a pivot arm axis that extends in a generally transverse orientation with respect to the chassis, said pivot arm assembly carrying the blade and blade-folding hinge at its rearward end.

4. A vehicle as in claim 3 comprising resilient pressure actuator means extending between the chassis and the pivot arm assembly to apply downward pressure to the blade, directing the scraping edge to press resiliently against a road surface beneath the vehicle.

5. A vehicle as in claim 4 wherein said blade support means comprises rotational means to allow the blade to tilt, thereby elevating one of the outer ends of the blade with respect to the other.

6. A vehicle as in claim 4 wherein the pressure actuator means comprises pneumatic bladders.

7. A vehicle as in claim 5 wherein the pressure actuator means comprises pneumatic bladders.

8. A vehicle as in claim 1 comprising a blade-folding actuator carried by said pivot arm assembly and coupled to said chassis to both swing the scrapping edge upwardly and to thereby elevate the blade by drawing the blade towards the chassis.

9. A vehicle as in claim 2 comprising a blade-folding actuator carried by said pivot arm assembly and coupled to said chassis to both swing the scrapping edge upwardly and to thereby elevate the blade by drawing the blade towards the chassis.

10. A vehicle as in claim 3 comprising a blade-folding actuator carried by said pivot arm assembly and coupled to said chassis to both swing the scrapping edge upwardly cause the pivot arm assembly to swing about the pivot arm axis) and to thereby elevate the blade by drawing the blade towards the chassis.

11. A vehicle as in claim 3 wherein said blade support means comprises a stop surface and said blade is positioned within the blade support means with its upper edge resting against the stop surface when the blade is deployed with its lower edge presented for scrapping a road surface beneath the vehicle.

12. A vehicle as in claim 2 wherein said blade support means comprises a stop surface and said blade is positioned within the blade support means with its upper edge resting against the stop surface when the blade is deployed with its lower edge presented for scrapping a road surface beneath the vehicle.

13. A vehicle as in claim 3 wherein said blade support means comprises a stop surface and said blade is positioned within the blade support means with its upper edge resting against the stop surface when the blade is deployed with its lower edge presented for scrapping a road surface beneath the vehicle and said stop surface is formed on said pivot arm assembly.