IE20070059U1 - A post driver - Google Patents

Abstract

ABSTRACT A post driver has a support frame with means for attachment to a carrier vehicle. A mast is mounted on the support frame. A hammer is slidably mounted on the mast for movement between raised and lowered positions on the mast. A hammer actuating assembly is operable for raising the hammer on the mast for release to drive a post. the hammer actuating assembly has a hamer lifting rope having a first end atttached to the hammer and a second end attached to the mast, said rope extending upwardly from the hammer and around a fixed pulley which is rotatably mounted on the mast and then downwardly and around a movable pulley and then upwardly to an anchor point on the mast to which said second end of the rope is attached. Drive means is operable for moving the movable pulley away from the fixed pulley for raising the hammer. the movable pulley is rotatably mounted on a carriage, said carriage slidably engaging the mast. The drive means is a ram connected between the carriage and a ram mount on the mast below the carriage.

Description

Introduction This invention relates to post drivers for driving posts into the ground.

We have described a number of post drivers for mounting on the three point linkage of a tractor in our earlier patent application — Publication No. GB 2,420,367. These essentially comprise a support frame for attachment to a tractor or the like, a mast on the support frame on which a hammer is slidably mounted for movement between raised and lowered positions and means for raising the hammer on the mast for release to drive a post.

The present invention is directed towards providing a novel actuating assembly for raising the hammer on the mast.

Statements of Invention According to the invention, there is provided a post driver, including: a support frame with means for attachment to a carrier vehicle, a mast mounted on the support frame, a hammer slidably mounted on the mast for movement between raised and lowered positions on the mast, a hammer actuating assembly for raising the hammer on the mast for release to drive a post, said hammer actuating assembly including a hammer lifting rope having a first end attached to the hammer and a second end attached to the mast, said rope extending upwardly from the hammer and around a fixed pulley which is rotatably mounted on the mast and then downwardly and around a movable Jéwiooss pulley and then upwardly to an anchor point on the mast to which said second end of the rope is attached, and drive means for moving the movable pulley away from the fixed pulley for raising the hammer. in one embodiment of the invention, the movable pulley is rotatably mounted on a carriage, said carriage being movable along on the mast.

Conveniently the carriage may slidably engage the mast.

In another embodiment, the drive means is a ram connected between the carriage and a ram mount on the mast below the carriage.

In another embodiment, a pulley mount is provided at the top of the mast on which the fixed pulley is rotatably mounted.

In a further embodiment, the rope anchor point for the second end of the rope is provided on the pulley mount.

In another embodiment, the mast comprises an I-section beam having an inner flange and an outer flange which are substantially parallel and spaced-apart, said flanges being interconnected by an intermediate web which is substantially perpendicular to said flanges.

In a preferred embodiment, the carriage is slidably mounted on the inner flange and the hammer is slidably mounted on the outer flange. in another embodiment, a post cap associated with the hammer is slidably mounted on the mast beneath the hammer. in a further embodiment, the mast is pivotally mounted on the support frame.

In a particularly preferred embodiment, a tilt ram is mounted between the support M ii) 059 frame and the mast, said tilt ram being operable to pivot the mast relative to the support frame. in another embodiment, the support frame has means for attachment to an excavator vehicle hitch.

In another arrangement, the support frame has means for attachment to a three point linkage of a tractor vehicle.

Detailed Description of the Invention The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a post driver according to the invention, and Fig. 2 is a side elevational view of the post driver.

Referring to the drawings, there is illustrated a post driver according to the invention, indicated generally by the reference numeral 1. The post driver 1 has a support frame 2 with an excavator hitch 3 for attachment to a digger vehicle. A mast 4 is mounted on the support frame 2. A hammer 5 is slidably mounted on the mast 4 for movement between a raised position at a top of the mast 4 and a lowered position, as shown in the drawings. A hammer actuating assembly, indicated generally by the reference numeral 8, is operable for raising the hammer 5 on the mast 4 for release to drive a post.

The actuating assembly 8 includes a hammer lifting rope 10 having a first or outer end 11 attached by a pin 12 between a pair of upstanding lugs 14 on top of the hammer 5. The rope 10 extends upwardly from the hammer 5 and around a fixed pulley 15 which is rotatably mounted by a pivot pin 16 on a pulley mount 17 fixed at a top of the mast 4. The rope 10 then passes downwardly and around a movable pulley 18 and then back upwardly to an anchor point 19 on the pulley mount 17 at the ifi 0 7 0 0 5 9 top of the mast 14 to which the second or inner end 20 of the rope 10 is attached.

The movable pulley 18 has a pulley wheel (not shown) rotatably mounted by a spindle 22 between a pair of substantially parallel spaced-apart mounting plates 23.

These mounting plates 23 are attached to a slide block 25 which slidably engages the mast 4. The slide block 25 forms a carriage for the movable pulley 18.

A hammer lifting ram 26 has a cylinder 27 with an outwardly extending piston rod 28.

A lower end of the cylinder 27 is attached by a lower mounting pin 29 at a bottom of the mast 4. An upper end of the piston rod 28 is attached by an upper mounting pin to the movable pulley 18. Retraction of the piston rod 28 into the cylinder 27 slides the movable pulley 18 downwardly on the mast 4, thus raising the hammer 5 on the opposite side of the mast 4. It will be noted that due to the engagement of the rope 10 around the movable pulley 18 movement of the hammer 5 will be twice the distance of the hammer lifting ram 26 stroke.

The mast 4 is of I-section having an inner flange 35 and an outer flange 36, said flanges 35, 36 being interconnected by an intermediate web 37. The slide block , which forms a carriage for the movable pulley 18, is slidably mounted on the inner flange 35. The slide block is C-shaped in section. wrapping around the inner flange 35 at each side of the inner flange 35. At the opposite side of the mast 4, the hammer 5 is slidably mounted on the outer flange 36, the hammer 5 having slide elements 38 for slidably engaging the outer flange 36. A post cap 40 is also slidably mounted on the outer flange 36 beneath the hammer 5.

The mast 4 is pivotally mounted on the support frame 2 by means of a pivot pin 45 which engages between the support frame 2 and mounting brackets 46 which extend ream/ardly from the mast 4. A tilt ram 48 is mounted between the support frame 2 and the mast 4 and is operable to tilt the mast 4 relative to the support frame 2. The tilt ram 48 connects to the support frame 2 by pivot pin 50 and to the mast 4 by pivot pin 51.

Hydraulic control levers 55 for operation of the rams 26, 48 are provided at a control station 56 mounted at one side of the mast 4. The rams 26, 48 can iEo7oo59 conveniently be connected to an hydraulic power supply on the vehicle on which the post driver 1 is mounted for operation of the rams 26, 48.

In use, the post driver 1 is positioned at a post with the cap 40 sitting on top of the post. The hammer lifting ram 26 is operated by retracting the piston rod 28 into the cylinder 27 to pull down the movable pulley 18, thus raising the hammer 5 on the mast 4. Upon releasing ram pressure, the hammer 5 drops downwardly striking the cap 40 and driving the post into the ground.

It will be appreciated that other arrangements for pulling the movable pulley 18 downwardly on the mast 4 to raise the hammer 5 may be provided. Further, different attachments for mounting the support frame 2 on a carrier vehicle may be provided. In the embodiment shown, an excavator hitch 3 is provided on the support frame 2. However, the support frame 2 could be adapted for attachment to the three point linkage of a tractor, for example.

It is also envisaged that instead of the rope 10, other types of flexible connector may be provided for lifting the hammer 5, for example, cables, chains and the like.

Bias means may be provided to aid ram 26 extension and reduce drag on the hammer 5 as it falls. Such bias means may for example comprise a spring mounted between the movable pulley 18 and the pulley mount 17 at the top of the mast 4, said spring being tensioned as the ram 26 pulls down the movable pulley 18. The bias might also possibly be provided by hydraulic pressure in the cylinder to raise the piston rod 28.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

M4795-6 BRENNAN SPEC 31JAN07

Claims (3)

1. A post driver, including: a support frame with means for attachment to a carrier vehicle, a mast mounted on the support frame, a hammer slidably mounted on the mast for movement between raised and lowered positions on the mast, a hammer actuating assembly for raising the hammer on the mast for release to drive a post, said hammer actuating assembly including a hammer lifting rope having a first end attached to the hammer and a second end attached to the mast, said rope extending upwardly from the hammer and around a fixed pulley which is rotatably mounted on the mast and then downwardly and around a movable pulley and then upwardly to an anchor point on the mast to which said second end of the rope is attached, drive means for moving the movable pulley away from the fixed pulley for raising the hammer, the movable pulley being rotatably mounted on a carriage, said carriage being movable along on the mast, said carriage slidably engaging the mast, and the drive means is a ram connected between the carriage and a ram mount on the mast below the carriage.

2. A post driver as claimed in claim 1 wherein a pulley mount is provided at the top of the mast on which the fixed pulley is rotatably mounted, and the rope anchor point for the second end of the rope is provided on the pulley mount.

3. A post driver as claimed in any preceding claim wherein the mast comprises an I-section beam having an inner flange and an outer flange which are substantially parallel and spaced-apart, said flanges being interconnected by an intermediate web which is substantially perpendicular to said flanges, the carriage is slidably mounted on the inner flange and the hammer is slidably mounted on the outer flange and a post cap associated with the hammer is slidably mounted on the mast beneath the hammer. A post driver as claimed in any preceding claim wherein the mast is pivotally mounted on the support frame, a tilt ram is mounted between the support frame and the mast, said tilt ram being operable to pivot the mast relative to the support frame. A post driver substantially as hereinbefore described with reference to the accompanying drawings.