GB2147185A

GB2147185A - Height adjustment for garden tools

Info

Publication number: GB2147185A
Application number: GB08424499A
Authority: GB
Inventors: Alan Trelford
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 1983-09-29
Filing date: 1984-09-28
Publication date: 1985-05-09
Also published as: GB8424499D0; DE8428123U1; AU563766B2; FR2552619A1; GB2147185B; FR2552619B1; AU3368184A; GB8326143D0

Abstract

A height adjustment mechanism for a garden tool comprises a cylindrical height adjustment member (7, Figure 1) rotatably mounted in the body of the tool and coupled at its inner end to a roller 40 of the tool. An axle 14 on member 7 co-operates with a centrally located bore 14a of roller 40 whereby the axis of rotation of the roller 40 is off set from that of the cylindrical member 7 so that, by rotating the latter, the height of the tool body from the ground can be adjusted. A locking projection (19, Figure 2) is formed on a tongue (15) in the cylindrical member (7) and can engage in a plurality of recesses 37 in the tool body to lock the cylindrical member (7) in a plurality of discrete rotational positions. The tongue (15) carries a button (18) by which it can be depressed, to release the lock and permit rotation of the cylindrical member. <IMAGE>

Description

SPECIFICATION Height adjustment for garden tools This invention relates two a garden tool, for example a grass sca rifier or cutter, with a height adjustment mechanism to adjust the height of an operational part ofthe machine relative to the ground.

A wide variety of height adjustment mechanisms have been designed, particularly for grass cutters. A common type of mechanism involves adjusting the position of a roller or a pair of wheels on which the machine is supported relative to the body ofthe machine. One such simpleform of mechanism involves mounting a wheel at one apex of a triangular plate; a second apex of the plate is pivotally connected to the body ofthe machine andthethird apex carries a transverse boltwhich is slidable in a groove in the body of the machine when the plate pivots and which can be clamped in position bytightening a nut. While such an arrangement is simple and relatively cheap it is not particularly simplefora user to operate.

It is an object ofthe invention to provide a garden tool with a heightadjustment mechanism which is simple to manufacture and simple to operate.

According to the invention there is provided a garden tool including a wheel or rollerfor supporting the tool body on the ground and a height adjustment mechanism comprising an adjusting member rotatably mounted on the tool body, and locking means for locking the adjusting member in a plurality of discrete rotational positions; the wheel or roller being coupled to the adjusting member with the axis of rotation of the wheel or roller offsetfrom the axis of rotation of the adjusting member.

A height adjustment mechanism ofthe kind defined above can be simply made and can provide a mechanism that is simple for a user to operate.

The locking means may beformed in the adjusting member and may be resiliently engageable in a plurality of recesses in the tool body, each of which defines a respective one ofthe discrete rotational positions. The locking means may comprise an outwardly-projecting partofthe adjusting member and is resiliently-movable inwardly ofthe adjusting member to permit rotation ofthe adjusting member.

Preferably the locking means is an integral part of the adjusting member. The locking means may, for example be located on a resiliently-deformableton- gueformed in the adjusting member. In an embodiment ofthe invention, the adjusting member is substantially cylindrical and the tongue extends longitudinally in the curved surface thereof. Such an arrangement simplifies manufacture of the height adjustment mechanism.Thetongue may be resiliently biased by a spring located within the cylinder.

The locking means may include an actuating memberoperableto release the locking means. When the locking means is located on a resiliently-deformable tongue, the actuating member may be located on thetongue adjacent the locking means.

In the above-mentioned embodiment of the invention, the cylindrical adjusting member has an integral control knob at one end and the tongue isjoined to the remainder of theadjusting member adjacent the other end thereof, the locking means being located adjacent the control knob. In this embodiment, the intermediate part of the adjusting member is rotatably mounted on the tool body and the wheel or roller is coupled to the adjusting member at the said other end.

The adjusting member may be shaped to provide more than one location at which the wheel or roller can be coupled thereto.

The adjusting member may be removablefrom the tool body and out of engagement with the wheel or roller.

The present invention further provides a height adjusting mem ber for a garden tool, the adjusting member being shaped to be rotatably mounted on the tool body and including locking means for locking the adjusting member in a plurality of discrete rotational positions relative to the tool body, and means for mounting a wheel or roller ofthe garden tool on the adjusting member with the axis thereof offset from the axis of rotation of the adjusting member.

By way example, embodiments of the invention will now be described with reference to the accompanying drawings, ofwhich: Fig. lisa perspective view of a lawn scarifier incorporating a height adjustment mechanism, Fig. 2 is a side view of a height adjusting member employed in the height adjustment mechanism, Fig.3 is an end view ofthe member of Fig. 2, Fig. 4 is a sectional view along the line IV-IV of Fig. 3, Fig. 5 is a viewfrom the other end ofthe member of Fig. 3, Fig. 6 is a sectional view along the lineVI-VI of Fig. 5, Figs. 7a and 7b are, respectively a side view of a part ofthe lawn scarifier on which a modified height ajusting member is aboutto be mounted, and an end view of that height adjusting member, Fig. 8 is a sectional view along the line VIII-VIII of Fig.

7a, Figs. 9a to care views similar to Fig. 7a butwith the height adjusting member mounted on the scarifier and shown in a different position in each Figure, Fig. 10 is a sectional view along the line X-X of Fig.

9b, Fig. 11 is a view corresponding to Fig. 2 showing another modification to the height adjusting member of Figs. 2 to 6, Fig. 12 isa viewalongthe lineXII-XII of Fig.9, and Fig. 13 is a view corresponding to Fig. 4showing the modified height adjusting member of Figs. 11 and 12.

The lawn scarifiershown in Fig. 1 has a body 1, a handle 2 (most of which is not shown), a tine assembly 3 rotated, in use, by a motor (not shown), a pair of front wheels5 and a rear roller (not visible in Fig. 1 but shown at40 in Figs. 7,9 and 10) the height of which is adjustable by a pair of height adjustment mechanisms 6 on opposite sides ofthe body 1; one ofthe height adjustment mechanisms is visible in Fig. 1. The present invention is concerned primarily with the height adjustment mechanism and the construction of other parts ofthe tool will not therefore be described in detail. Our European patent application, publication No. 24696, describes one form of scarifying tool on which the height adjustment mechanism 6 may be employed.

The main component of each height adjustment mechanism 6 is a heightadjustmentmember7 coupled to a respective end of the roller 40 as will be described below. One ofthe height adjustment members isshown in Figs. 2 to 6 and the construction ofthe memberwill now be described.

The member7 is of generally hollow cylindrical form and is moulded in one piece from plastics material. At one end (which in use is the outer end), the member is closed over and formed as a control knob 8 with castel lations 4 in its curved surface providing a ribbed effect to aid gripping ofthe knob. Atthe interface of the knob 8 with the remainderofthe member7 a flange 9 is provided. A central part 10 of the member7 has a substantially circular external cross section but along a common circumference of the member a pair of projections 11 are formed. These projections lie approximately diametrically opposite one another but are offsetfrom direct opposition by an angle of about 7"to 8".

Formed within the member 7 are a pair of cylindrical pockets 12, the open ends of which face towards the inner end of the member7 (that is, the end opposite the control knob 8). The axes of these cylindrical pockets 12, 13 are parallel to but offset from the axis ofthe member7,the pockets being disposed one on each sideofthelatteraxis. Oneonlyofthe pockets receives a roller mounting axle 14which is a press fit within the pocket. In the case of a member7 to be fitted on one side of the tool the axle 14 is fitted in the pocket 12 while for a member7 to be fitted on the opposite side of the tool the axle 14 is fitted in the pocket 13.

In use, the axles 14, one on each side ofthetool, are located centrally in the ends ofthe roller 40 and serve to mountthe roller rotatably in thetool, aswill be described in greater detail below.

A longitudinally extending tongue 15 is formed in the periphery ofthe cylindrical 7 by a pair of longitudinal slots 16 and a transverse slot 17 close to the outer end of the control knob 8 and interconnect ins the slots 16. The slots 16,17 cut right through the wall ofthe cylindrical member7 leaving the tongue 15 joined to the remainder ofthe member7 adjacentthe inner end remote from the control knob 8.However, the tongue 15 in its natural state (shown in the drawings) provides in most areas a smooth continuation to the periphery of the member 7. At its distal end (the outer end), the tongue 15 intersects the ribbed surface 4ofthe knob 8 and the flange 9 and is formed with an outwardly-projecting endless flange 18 of rectangular shape which constitutes a button (see Figs. 3,4 and 5) by which the tongue 15 can be depressed. Immediately inside the flange 18 a much shallowerflange 19 is provided, which is joined to the flange 18 by a pairof shortsidewalls walls 20. As can be seen in Figs. 2 and 4theflange 19 is located inside the line oftheflange 9. The flange 19 serves as a locking element during height adjustment as will be described below.

Figs. 7a and 8 showthat portion of the body 1 of one side of the scarifier in which a height adjusting member7 isto be mounted. The body 1 has parallel spaced outerand innerwalls30 and 31 having openings 32 and 33 respectively in which the member 7, in use, is mounted. The opening 33 issimplya circular hole in which, in use, the inner end of the adjusting member7 is rotatably located.

The opening 32 is generally circular but is enlarged by two recesses 34 which lie approximately opposite one another but are offsetfrom directopposition by an angle of about 70to 80. Around the outside of the opening 32 the wail 30 is thickened to define an annularwall 35. The inside ofthe wall 35 is formed with a pair of recesses which are continuations ofthe recesses 34 and at the outer end with three additional recesses 37 spaced at90 intervals around the wall and extending through the whole thickness of the wall.

Fig. 7b shows the inner end ofthe height adjusting member7 that is to be mounted on the side ofthe scarifier shown in Figs. 7a and 8. Itwill be understood that Fig. 7b is a view similarto that of Fig. 5 but shows the member 7 in the orientation in which it is inserted into the openings 32,33, as will be described below.

The member7 shown in Fig. 7b differs slightly from that shown in Figs. 2 to 6 in that it incorporates a spring 41 locatedwithin the hollow cylindrical body of the member, the purpose of which spring will be described later. For the present, the member7 of Fig.

7b can be taken as being the same as that shown in Figs. 2to 6.

The manner in which the member7 is fitted onto the tool body 1 will be described with reference to Figs. 7 to 10. The member7 is inserted from the outside into the openings 32 and 33 on the body, with the inner end ofthe member (ie. that shown in Fig. 7b) first and in the orientation shown in Fig 7b. The recesses 34 in the opening 32 correspond in shape and position to the projections 1 1 or the ofthemember7andthereforeallow full insertion ofthe member7 in this one orientation only, in which the projections 11 are aligned with the recesses.In order to accommodate the flange 19 the distal end ofthetongue is depressed by a user pressing on the bottom 18 asthe member7 is being inserted and, during this process, the axle 14 on the member 7 entersthe bore of a centrally-located cylindrical extension 14a on the end face of the roller cylindrical extension 1 4a on the end face of the roller 40, thereby mounting the roller on the axle. Inward movement of the member 7 is halted when the flange 9 meets the outer end of the outer end ofthewall 35. At this position the member 7 is able to rotate with the projections 11 now being inside ofthe wall 30. As soon as the member7 is rotated it can no longer be withdrawn from the tool body owing to the engagement of the projections 11 with the wall 30.

Each ofthe three circumferentially spaced recesses 37 is able to accommodate the flange 19 as illustrated in Figs. 9 and 10 and, as the member7 is rotated after it has been inserted,theflange 19 will "click" into the firstofthosethree recesses (say, recess "1" in Fig. 9a) that it comes to and thereby locks the member7 in that position.To release the member the button 18is pressed inwardly by a user, thereby depressing the tongue 15 and moving theflange 19 out ofthe recess, whereupon the member7 can he rotated again until the flange 19 engages in the next recess 37 (recess "2" as shown in Fig. 9b). The three circumferentially spaced recesses 37 therefore define three different rotational positions in which the member7 can be locked.

It will be appreciated that because the axis ofthe axle 14 is offset from the axis of rotation ofthe member 7, the axle 14 is held in different positions relative to the tool body in each of the three locked positions of the member7.Thesethree different positions are indicated in Figs. 9ato cand are arranged to provide three different heights for the rear roller40 relative to the tool body as is also indicated in these Figures.

Fig. 10 shows a section through the member 7 in the height position "2" of Fig. 9b. Fig. 10 thus shows the flange 19 after it has "clicked" into the position "2" recess 37 in the wall 35 and showsthatthetongue 15 withthebutton 18isthen in its normal, undepressed, position. Fig. 10 also shows the above-mentioned engagement of flange 9 with the wall 35; the location ofthe inner end of member 7 in the inner wall opening 33, and the mounting ofthe roller 40 on the axle 14.

Also shown in Fig. 10 is a strengthening web 14b (which also appears in Fig. 7a) forthe cylindrical extension 14a ofthe roller, in which the axle 14 is located.

Itwas mentioned above that the member7 incorporates a spring 41 (shown in Figs. 7b and 10). The purpose of this spring is to assistthe natural resilience ofthetongue 15 and ensurethatthe latter is positively-biased towards its normal, undepressed, position and, thereby, to ensure positive engagement oftheflange 19 in the appropriate one ofthe recesses 37 when the button 18 is released. As shown, the spring 41 is generally "S"-shaped with one arm ofthe "S" lying underneath the tongue 15, the end of that arm being turned over and located underneath the button 18.

As will be apparent from the description above, a user adjusts the height ofthe tool by rotating both of the members 7 between the respective locked positions indicated by "1", "2" and "3" in Figs. 7a and 9ato C. These indications, or similar markings, can be provided on the tool body to indicate the locked positions and the height adjustmentthey provide.

Most conveniently, the members 7 on both sides of the tool bodyareadjustedtogetherbutthe mounting ofthe roller on the axles 14 is arranged to allow sufficient playforthe height adjustment to be made on one side ofthe tool before the other.

In the case of the scarifying tool described above, the highest setting of the tool may cause the tine assembly 3 to pass overthe top ofthe ground in primarily a raking rather than scarifying action; the middle setting may provide a light scarifying action; and the lowest setting may provide a heavy scarifying action.

If,forany reason, it becomes necessary to remove either ofthe height adjusting members 7 or the roller 40 then this is done by rotating the member7 out of the normal height adjusting range and into the orientation shown in Fig. 7b and then reversing the insertion procedure described above.

The height adjustment mechanism described above is simple both to manufacture and to operate.

While in the embodiment describedthree height adjustment settings are provided it will be clearthat the embodiment could readily be modified to provide a greater number of settings. Also, the height adjustment may be used on wheels ratherthan a roller.

Figs. 11, 12 and 13 show an alternative cross-section for the tongue 15 which gives the tongue greater stiffness and yet still enables the member7to be moulded in one piece. As most clearly seen in Fig.11, the tongue has a pair of longitudinally ribs 38 along its side edges. The outersurfaces ofthe ribs 38 line up with the outer surface of the member7 while the remaining part of the tongue is recessed inwardly therefrom.

Claims

1. A garden tool including a wheel or rollerfor supporting the tool body on the ground, and a height adjustment mechanism comprising an adjusting member rotatably mounted on the tool body, and locking means for locking the adjusting member in a plurality of discrete rotational positions; the wheel or roller being coupled to the adjusting member with the axis of rotation ofthe wheel or roller offset from the axis of rotation ofthe adjusting member.

2. Atool as claimed in claim 1, in which the locking means is formed in the adjusting member and is resilientlyengageable in a plurality of recesses in the tool body, each recess defining a respective one of the discrete rotational positions.

3. Atool as claimed in claim 2, in which the locking means comprises an outwardly-projecting part of the adjusting member and is resiliently-movable inwardly ofthe adjusting memberto permit rotation of the adjusting member.

4. Atool as claimed in claim 3, in which the locking means is an integral part ofthe adjusting member

5. Atool as claimed in claim 4, in which the locking means is located on a resiliently-deformable tongue formed in the adjusting member.

6. Atool as claimed in claim 5,in which the adjusting member is substantially cylindrical and the tongue extends longitudinally in the curved surface thereof.

7. Atool as claimed in claim 6, in which the tongue is resiliently biased by a spring located within the cylinder.

8. Atool as claimed in anyone ofthe preceding claims, including an actuating memberoperableto release the locking means.

9. Atool as claimed in claim 8when appendentto claim 5, in which the actuating member is located on the tongue adjacent the locking means.

10. Atool as claimed in claim 6, in which the cylindrical adjusting member has an integral control knob at one end and the tongue is joined to the remainder of the adjusting member adjacentthe other end thereof, the locking means being located adjacent the control knob.

11. Atool as claimed in claim 10, in which the intermediate part ofthe adjusting member is rotatably mounted on the tool body.

12. Atool as claimed in claim 10 or claim 11, in which the wheel or roller is coupled to the adjusting member atthe said other end.

13. Atool as claimed in any one ofthe preceding claims, in which the adjusting member is shaped to provide more than one location atwhich the wheel or roller can be coupled thereto.

14. Atool as claimed in any one ofthe preceding claims, in which the wheel or roller is mounted on an axle which extends from the adjusting member parallel to but off set from the axis of rotation of the adjusting member.

15. Atool as claimed in claim 14when appendent to claim 13, in which the adjusting member is shaped to provide at least one alternative location forthe axle.

16. Atool as claimed in any one of the preceding claims, in which the adjusting member is removable from the tool body and out of engagement with the wheel or roller.

17. Atool as claimed in claim 16, in which the adjusting member is removable from the tool body in one orientation only.

18. A height adjusting memberfor a garden tool, the adjusting member being shaped to be rotatably mounted on the tool body and including locking means for locking the adjusting member in a plurality of discrete rotational positions relative to the tool body, and means for mounting a wheel or roller ofthe garden tool on the adjusting memberwith the axis thereof offset from the axis of rotation of the adjusting member.

19. Aheightadjusting member as claimed in claim 18, the member being substantially cylindrical with an integral control knob at one end and having an axle at the other end for mounting the wheel or roller of the garden tool,the locking means being located on a longitudinally extending tongue in the curved surface ofthecylindrical member.

20. Aheightadjusting memberfora garden tool, substantially as described herein with reference to, and as shown in Figs. 2to 6 or Figs. 11 to 13 ofthe accompanying drawings or Figs. 2 to 6 as modified by Fig. 7bofthe accompanying drawings.

21. A garden tool substantially as described herein with reference to, and as shown in, Figs. 1 to 10 ofthe accompanying drawings or Figs. 1 to 10 as modified by Figs. 11 to 13 of the accompanying drawings.