GB2099892A

GB2099892A - Snow plough

Info

Publication number: GB2099892A
Application number: GB8213201A
Authority: GB
Original assignee: BIG J AUTO PARTS Ltd
Current assignee: BIG J AUTO PARTS Ltd
Priority date: 1981-05-08
Filing date: 1982-05-07
Publication date: 1982-12-15
Also published as: GB2099892B

Abstract

A snow plough has a framework (1) having rear arms (3, 4) securable at their rear ends to the front of a vehicle and a forward part (2) to which a blade (5) is pivoted about a vertical pivot (6). The forward part (2) of the frame is formed in two parts (2a, 2b) with a parallelogram linkage with horizontal pivots between the two parts (2a, 2b). Control members (7, 8) can be lengthened or shortened selectively to slew the blade (5) about the pivot (6) or to raise the blade (5) about the parallelogram linkage to an inoperative position. The control members (7, 8) include electric motors to be powered from the electrical system of the vehicle on which the snow plough is mounted. <IMAGE>

Description

SPEICIFICATION Snow plough The invention relates to snow ploughs.

Snow ploughs are widely held ready for use in geographical areas where there is a likely incidence of heavy snow and generally comprise a framework pivotably mounting a blade which is usually formed in the shape of a segment cf a cylinder, the framework having means whereby it can be hitched to the front of a specially adapted vehicle, such as a lorry or a tractor, and including a pivot and a pair of hydraulic rams whereby, on coupling the hydraulic rams to a hydraulic system of the vehicle, the blade can be pivoted about the pivot to change the angle which the blade makes with the direction of forward motion of the vehicle.

A third hydraulic ram may be provided to raise and lower the blade. In operation, the blade is lowered so that it rests lightly upon the surface to be cieared and the vehicle is driven forwardly, the blade normally being angled so that one side, for example the nearside, is trailing rearwardly with respect to the other side so that snow picked up by the blade slides laterally across the blade to be deposited at a longitudinal position corresponding to the path of the nearside of the blade.

While snow ploughs used on such vehicles can be effective in clearing roads and airport runways, vehicles with the necessary hydraulic attachments are not always readily available for use for clearing snow from relatively small areas such as vehicle service station forecourts and car parks of hotels and in consequence such areas have in the past usually either been left snow covered or have been cleared of snow manually.

According to the invention a snow plough comprises a framework engageable with hitch means at the front end of a vehicle, the framework including means allowing a front part thereof to be moved upwardly with respect to a rear part thereof, a plough blade pivotably mounted on the front part of the framework about a generally upright pivot axis, a pair of control members each coupled between the rear part of the framework and a respective position on the blade spaced laterally from the pivot axis and control means for varying the length of the control members, the control means including electric motors to be powered from the electrical system of the vehicle to which the snow plough is to be attached.

The means allowing a front part of the framework to be moved upwardly with respect to the rear part preferably comprises a parallelogram linkage with generally horizontal, transverse pivots such that as the front part of the framework is raised it moves rearwardly with respect to the rear part but remains in its original orientation.

An upper link of the parallelogram linkage is preferably formed by a fixed length bar but the lower link can be formed by a tension spring, preferably with a stiffening member associated therewith to prevent it bending, the spring acting as a solid member when in compression but being elongated when in tension to enable the blade to tilt rearwardly about a forward upper one of the transverse pivots of the parallelogram linkage when the blade is pressed downwardly by the control members.

Preferably the control members each comprise an elongate threaded member co-operating with a recirculating ball nut and driven for rotation by a respective one of the electric motors such that rotation of the threaded member causes lengthening or shortening of the control member.

The framework is preferably of generally Y-form with the rear part formed by the fork arms thereof and a part of the stem thereof and with the free ends of the two fork arms coupled by upright linch pins to respective brackets securable to the hitch means of a vehicle. The parallelogram linkage is advantageously provided intermediate the ends of the stem of the Y-form framework and the upright pivot axis at the free end of the stem.

The control members are preferably mounted at one of their ends on upstanding projections from respective ones of the fork arms and at the other of their ends are mounted approximately midway between a respective outer end of the blade and the upright pivot axis and low down on the blade, the mountings to the blade being effected by linch pins.

Alternatively the framework can be of generally T-form with the rear part formed by the bar thereof and part of the stem thereof and with the free ends of the bar of the T-form framework coupled by upright linch pins to respective brackets securable to the hitch means of a vehicle.

The parallelogram linkage is advantageously provided intermediate the ends of the stem of the T-form framework and the upright pivot axis of the free end of the stem.

The control members are preferably mounted at their rear ends on shear pins extending through webs provided at the junction of the bar and the stem of the T-form framework on respective opposite sides of the stem and at their forward ends are mounted approximately midway between a respective outer end of the blade and the upright pivot axis and low down on the blade.

Operation of the two electric motors in opposite senses, that is to say to shorten one control member and to lengthen the other, will change the angle of the blade with respect to the framework by pivoting the blade about the upright pivot axis, one side of the blade being pulled back and the opposite side of the blade being pushed forward. If both electric motors are operated simultaneously and in the same sense, that is to say to shorten or lengthen both control members, the blade will be raised or lowered by movement of the parallelogram linkage.

The lower end of the blade is preferably formed by relatively short lengths of strip material bolted to the remainder of the blade, said lengths being readily replaceable if damaged or when they become unduly worn. The strip material is preferably rigid polyethylene.

Advantageously wheels are mounted on the snow plough at positions adjacent the outer end of the blade and at the rear of the blade, the lower surface of the wheels being located art a height slightly above the level of the lower end of the blade.

While the invention has been described with reference to a snow plough, it will be apparent that when fitted to a vehicle it can be used tor shifting materials other than snow, for example gravel or animal manure, in the manner of a small bulldozer.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which Figure 1 is a plan view of a first embodiment of a snow plough according to the invention; Figure 2 is a side view corresponding to Figure 1; Figure 3 shows the construction of one of a pair of control members; and Figures 4 and 5 are views similar to Figures 1 and 2 respectively of a second embodiment -of snow plough according to the invention.

Referring to the drawings and firstly to Figures 1 to 3, a snow plough comprises a framework 1 having a stem 2 and fork arms 3, 4, a blade 5 coupled to the stem 2 by a pivot pin 6 and control members 7 and 8 for positioning the blade 5.

The free 'end of each of the fork arms 3, 4 is coupled to a respective bracket 9, 10 by respective link pins 11, 1 2 and Figure 2, at the lefthand side thereof, shows that each bracket 9, 10 can be coupled to a chassis member 13 provided at the front of a vehicle orto a special bracket provided at the front end of the vehicle by means of four bolts 14 which extend through lugs 15 provided on the brackets 9, 10 so that the Yshaped frame 1 is cantilevered out in front of the vehicle.

A rear part 2a of the stem 2 is formed as an upwardly open channel member and a forward part 2b of the stem 2 is formed as a downwardly open channel and is coupled to the portion 2a by means of a parallelogram linkage formed by an upper link 1 6, a lower link 17 and four transversely extending horizontal bolts 18, the bolts 1 8 extending through the respective links 16, 17 and through side plates of the channel members 2a, 2b of the stem 2. The portion 2b can be moved, while maintaining its horizontal orientation, from the position of Figure 2 to a position in which the links 16, 1 7 extend substantially vertically and the link 1 6 is in abutment with the front edge of a stop plate 1 9 welded across the top of the channel member 2a.

The blade 5 is of part-cylindrical form and is coupled to a blade frame comprising channel members 21 and angle members 22 secured to upper and lower box-section members 23, 24 secured to the blade 5, the other ends of the channel members 21 and the angle members 22 being secured to a sleeve 25 through which the pivot pin 6 extends, the pivot pin 6 also extending through spaced lugs 26 projecting forwardly from the part 2b of the stem 2 of the framework 1.

At its lower edge adjacent the box-section member 24, the blade 5 mounts an angle bracket 27 with apertures therein whereby toe plates 28 can be secured by means of bolts 29. Figure 1 shows that there are ten toe plates 28 and the toe plates 28 are preferably formed of rigid polyethylene.

A pair of wheels 30 are mounted on respective castors 31 with pivot pins 32 of the castors engaged in sleeves 33 mounted on the frame of the blade 5. The wheels 30 are preferably so mounted that their under surfaces lie in a horizontal plane which extends approximately one inch above the lower edge of the two plates 28 such that in operation the toe plates are, by their .engagement with the ground, bent upwardly so thattheirforward edges are raised by approximately one inch to give them a curvature which continues the curvature of the part cylindrical blade 5.

A respective bracket 34, 35 is mounted approximately midway along the length of each of the fork arms 3, 4 of the frame 1 and each mounts, in a ball joint 36, 37, the respective control member 7, 8. Each control member 7, 8 comprises an electric motor 40, 41, a rearward tubular member 42, 43 and a forward tubular member 44,45, the forward free ends of the tubular members 44, 45 being engages with pins, only one of which 46 is visible in Figure 2, extending downwardly from the frame of the blade 5, by means of ball joints, again only one of which 47 is visible in Figure 2.The electric motors 40, 41 are connected to a power connection lead 48 leading to a multi-pin plug 49 which can be connected to a complementary socket on the vehicle on which the snow plough is mounted whereby the electric motors 40, 41, preferably 12 volt DC motors, can be independently energised for rotation from the electrical system of the vehicle.

Figure 3 shows details of the internal construction of the control member 7, the control member 8 being identical therewith.

The motor 40 is secured by bolts 50 to a flange 51 secured by screws 52 to a sleeve 53 which is secured to the outer tube 42 and around which the ball joint 36 engages. The shaft 54 of the motor 40 is secured to a coupling member 55 mounted in a bearing 56 in the flange 51 and sleeve 53. A ball screw 57 is secured to the coupling member to rotate therewith and extends almost to the free end of the outer tube 42. The rear end of the inner tube 44 mounts a slide collar 58 with a recirculating ball nut 59 secured thereto. Rotation of the motor shaft 54 and thus the coupling member 55 and ball screw 57 will cause the ball nut 59 to move longitudinally of the ball screw 57 and will thus shorten or lengthen the control member 7 according to the direction of rotation of the motor shaft 54.

The controls provided in the vehicle for controlling the snow plough need merely comprise a forward/off/reverse control for each of the motors 40,41.

In operation, and from the position shown in Figure 1, if the motor 41 is energised in a sense to reduce the length of the control member 8 and the motor 40 is energised in a sense to increase the length of the control member 7, the blade 5 will slew about the pivot pin 6 so that the lefthand side of the blade 5, as viewed in Figure 1, is in a trailing position with respect to the righthand side of the blade such that, with the toe plates 28 of the blade 5 engaged with the ground and the vehicle driven forwardly, snow lying on the ground in the path of the vehicle will be engaged by the blade 5 and will slide transversely across the blade to be deposited in an extended pile just clear of the lefthand side of the blade.If the snow is to be diverted to the righthand side of the vehicle, then the motor 41 is energised in a sense to extend the control member 8 and the motor 40 energised in a sense to retract the control member 7 so that the blade 5 is slewed until its righthand end trails rearwardly from its lefthand end such that snow will then be diverted rightwardly.

The toe plates 28 will generally deform temporarily to pass over small obstructions in the path of the vehicle but if the blade should strike a large obstruction, then it can slew about the pivot axis 6 to avoid a sudden halt since the ratio of the screws 57 and nuts 59 of the control members 7, 8 is such that the motors 40, 41 can be rotated by force applied to the blade.

When the blade is required to be raised from the operating position, the motors 40, 41 are energised in a sense to retract both the control members 7 and 8 thereby to cause the forward member 2b of the stem 2 of the framework 1 to be pulled upwardly about the parallel linkage formed by the links 16, 17 and the bolts 18 so that the member 2b, while remaining parallel to the member 2a, is raised thereabove substantially by the length of the links 1 6, 1 7. In this position, the weight of the blade 5, the blade frame and the member 2b acting substantially vertically downwardly is not applied to the control members 7, 8 and there is therefore only a very limited tendency to move to the operating position and thus the front end will remain in the raised position without a separate clamp to secure it in this position being necessary.Due to the raised position and the consequent reduction in the forwardly extending length of the snow plough from the vehicle, the likelihood of the snow plough coming into engagement with the ground due to pitching of the vehicle as it passes over rough ground, is avoided.

If in operation with the plough blade 5 lowered, the blade engages a large obstruction head on, the plough blade 5 and forward end of the framework 1 can move about the parallel linkage towards the raised position to cushion the shock since the applied force can rotate the motors 40, 41 in a sense to shorten the control members 7, 8.

Advantageously the blade 5 can pivot through 400 about the pivot pin 6 either clockwise or anticlockwise from the position shown in Figure 1 and the change in height of the forward member 2b between the operating position and the fully raised position amounts to thirteen inches.

It can be seen by clamping the brackets 9, 10 to chassis members 1 3 of a vehicle, or providing special permanent hitch brackets 1 3 on a vehicle, and by providing a power socket and controls connected to the vehicle electrical system, a vehicle, which is preferably but not necessarily a four-wheel drive vehicle, can readily be adapted to mount a snow plough and can rapidly be fitted with the snow plough when there is a need to clear snow.

Referring now to Figures 4 and 5, a snow plough shown therein has many similarities with the snow plough of the embodiment of Figures 1 to 3 and only aspects of the embodiment of Figures 4 and 5 which differ from the embodiment of Figures 1 to 3 will be described. A framework 101 is substantially of T-form in that it has a stem 102 and a bar 103. The free ends of each of the ends of the bar 103 are coupled to respective brackets 109, by iink pins 111 and 112.

Control members 107 and 108 are coupled at their rear ends to the framework 101 by shear pins 134, 135 engaged in apertures in webs 1 34a, 1 34h which extend between the stem 102 and the bar 103. If, in use of the snow plough, the blade 105 thereof strikes an immovable object such that the blade 105 is forced rearwardly and upwardly at a speed faster than can be accommodated by shortening of the control members 107, 108, the shear pins 134,135 will shear to prevent damage to the relatively expensive control members 1 07, 1 08.

The parallelogram linkage in the stem 102 comprises an upper link 116 formed as a fixed length bar and a lower link 117 formed as a tension spring. A tubular stiffening member (not shown) is provided within the spring 11 7 to prevent the spring 11 7 from bowing. The spring 11 7 however can be elongated to enable the blade 105 together with the forward part 1 02b of the stem 102 to pivot, anti-clockwise as viewed in Figure 5, about an upper one 11 8a of forward pivot bolts of the parallelogram linkage.The lower end of the blade 105 may not be readily visible to an operator in a vehicle on which the snow plough is mounted and the operator thus cannot readily determine the moment at which, as the blade 105 is lowered by extension of the control members 107, 108, the lower end of the blade 105 engages the ground. If the control members 107, 108 are further elongated after the lower end of the blade 105 has engaged the ground, a lifting force will be applied to the front of the vehicle by the control members 107, 108. This is obviously undesirable and is avoided by providing the link 117 to be extendible such that further elongation of the control members 107, 1 08 after the lower end of the blade 107 has engaged the ground will cause the blade 105 together with the forward portion 1 02b of the stem 2 to pivot about the bolt 11 8a.

The upper end of the blade 105 is usually visible to the operator and when he can see rearward pivoting movement of the blade 105, he will know that the lower end of the blade 1 05 has engaged the ground.

Claims

1. A snow plough comprising a framework engageable with hitch means at the front end of a vehicle, the framework including means allowing a front part thereof to be moved upwardly with respect to a rear part thereof, a plough blade pivotably mounted on the front part of the framework about a generally upright pivot axis, a pair of control members each coupled between the rear part of the framework and a respective position on the blade spaced laterally from the pivot axis and control means for varying the length of the control members, the control means including electric motors to be powered from the electrical system of the vehicle to which the snow plough is to be attached.

2. A snow plough according to claim 1, in which the means allowing a front part of the framework to be moved upwardly with respect to the rear part comprises a parallelogram linkage with generally horizontal, transverse pivots such that as the front part of the framework is raised it moves rearwardly with respect to the rear part but remains in its original orientation.

3. A snow plough according to claim 2, in which an upper link of the parallelogram linkage is formed by a fixed length bar and a lower link is formed by a tension spring.

4. A snow plough according to claim 3, in which a stiffening member is associated with the tension spring to prevent it bending, the spring acting as a solid member when in compression but being elongated when in tension to enable the blade to tilt rearwardly about a forward upper one of the transverse pivots of the parallelogram linkage when the blade is pressed downwardly by the control members.

5. A snow plough according to any one of claims 1 to 4, in which the control members each comprise an elongate threaded member cooperating with a recirculating ball nut and driven for rotation by a respective one of the electric motors such that rotation of the threaded member causes lengthening or shortening of the control member.

6. A snow plough according to any one of claims 1 to 5, in which the framework is of generally Y-form with the rear part formed by the fork arms thereof and a part of the stem thereof and with the free ends of the two fork arms coupled by upright linch pins to respective brackets securable to the hitch means of a vehicle.

7. A snow plough according to claim 6 when appendantto claim 2, in which the parallelogram linkage is provided intermediate the ends of the stem of the Y-form framework and the upright pivot axis at the free end of the stem.

8. A snow plough according to claim 7, in which the control members are mounted at one of their ends on upstanding projections from respective ones of the fork arms and at the other of their ends are mounted approximately midway between a respective outer end of the blade and the upright pivot axis and low down on the blade, the mountings to the blade being effected by linch pins.

9. A snow plough according to any one of claims 1 to 5, in which the framework is of generally T-form with the rear part formed by the bar thereof and part of the stem thereof and with the free ends of the bar of the T-form framework coupled by upright linch pins to respective brackets securable to the hitch means of a vehicle.

10. A snow plough according to claim 9, in which the parallelogram linkage is provided intermediate the ends of the stem of the T-form framework and the upright pivot axis at the free end of the stem.

11. A snow plough according to claim 10, in which the control members are mounted at their rear ends on shear pins extending through webs provided at the junction of the bar and the stem of the T-form framework on respective opposite sides of the stem and at their forward ends are mounted approximately midway between a respective outer end of the blade and the upright pivot axis and low down on the blade.

12. A snow plough according to any one of claims 1 to 11, in which operation of the two electric motors in opposite senses, that is to say to shorten one control member and to lengthen the other, will change the angle of the blade with respect to the framework by pivoting the blade about the upright pivot axis, one side of the blade being pulled back and the opposite side of the blade being pushed forward.

13. A snow plough according to claim 12, in which operation of both electric motors simultaneously and in the same sense, that is to say to shorten or lengthen both control members, will cause the blade to be raised or lowered by movement of the parallelogram linkage.

14. A snow plough according to any one of claims 1 to 13, in which the lower end of the blade is formed by relatively short lengths of strip material bolted to the remainder of the blade, said lengths being readily replaceable if damaged or when they become unduly worn.

15. A snow plough according to claim 14, in which the strip material is rigid polyethylene.

16. A snow plough according to any one of claims 1 to 14, including wheels mounted on the snow plough at positions adjacent the outer end of the blade and at the rear of the blade, the lower surface of the wheels being located at a height slightly above the level of the lower end of the blade.

1 7. A snow plough substantially as hereinbefore described and illustrated with reference to the accompanying drawings.