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(11) | EP 0 133 814 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A portable power planer |
| (57) A portable power planer with depth of cut adjustment, has a shoe member (14) disposed
adjacent a planer blade shaft (3) and adjustable vertically with respect to a shoe
(4). Biasing means (23 or 123) urges the shoe member (14) into a raised position.
An upwardly extending member (15) is arranged to co-operate with an adjusting member
(19) for adjusting the depth of cut. The adjusting member (19) has a cam surface (22)
and the top end (18) of the upwardly extending member (15) is biased into contact
therewith, whereby the depth of cut is adjusted by rotation of adjusting member (19). |
[0002] It is known to provide a portable power planer comprising a casing, a shoe, a planer blade shaft, a shoe member disposed adjacent the shaft and adjustable vertically with respect to the shoe, biasing means urging the shoe member into a raised position, an adjusting member mounted on the casing, an upwardly extending member arranged on said shoe member and co-operating with said adjusting member for adjusting said depth of cut. The casing may be formed of plastics material, and the adjusting member may be mounted in an upper wall thereof.
[0003] In such a portable power planer disclosed in European O 048 304A the adjusting member comprises a rotary knob which is mounted in an upper wall of the planer casing. This rotary knob has a screwthreaded bore. The knob is mounted to be rotable about the longitudinal axis of the screwthreaded bore, but also is retained so as to be non-displaceable in the direction of the longitudinal axis. The upwardly extending member of the shoe member comprises a screwthreaded pin, which extends into the screwthreaded bore. The shoe member is also engaged by a tension spring which is retained via its other end in the casing. This tension spring thus exerts a tensile force on the shoe member which force is directed towards the raised position of the shoe member. Rotation of the rotary knob displaces the screwthreaded portion of the screwthreaded pin axially relative to the screwthreaded bore and thus varies the depth of the pin in the screwthreaded bore. This effects displacement of the non-rotatable shoe member in the vertical direction relative to the shoe. In this way the lower surface of the shoe member is displaceable into a position which ensures the required depth of cut when the lower surface of the shoe and also the lower surface of the shoe member bear against a workpiece.
[0004] Although this known portable power planer operates satisfactorily, it requires a precisely defined inclination for the wall of the planer casing receiving the rotary knob. It is only when that inclination is precisely defined that the lower surface of the shoe member will extend parallel with the lower surface of the planer shoe. Without that inclination being precisely defined, the lower surface of the shoe member adopts an inclined position. When the planer is assembled, this misalignment of that lower surface must then be corrected by expensive machining operations.
[0005] It has been found that, when the plastics casings of such planers are assembled, deviations repeatedly occur in the inclination of the upper wall of the casing which receives the adjusting member. These deviations occur even if a large number of precisely shaped casings or casing shells have first been produced with the die mould used.
[0006] The present invention seeks to provide a portable power planer with depth of cut adjustment, wherein the lower enrface of the adjustable shoe member may be aligned in parallel with the lower surface of the shoe even if the inclination of the upper wall of the planer casing receiving the adjusting member deviates in inclination from the required inclination.
[0007] According to one aspect of the present invention there is provided a portable power planer with depth of cut adjustment, comprising a casing, a shoe, a planer blade shaft, a shoe member disposed adjacent the shaft and adjustable vertically with respect to the shoe, biasing means urging the shoe member into a raised position, an adjusting member mounted on the casing, an upwardly extending member arranged on said shoe member, and co-operating with said adjusting member for adjusting said depth of cut, wherein the adjusting member defines a cam surface and the upwardly extending member has a top end co-operating with said cam surface. If the adjusting member takes the form of a rotary knob, the cam surface is preferably disposed circular.
[0008] In the embodiments therefore, the adjusting member and the shoe member are not rigidly interconnected, but each mounted separately in the planer casing and coupled to one another merely by a cam surface of the adjusting member bearing against the top end of the upwardly extending member. In this way, the adjusting member may be used to adjust the shoe member vertically, whilst avoiding misalignment of the shoe member lower surface. Deviations in the inclination of the casing wall receiving the adjusting member or displacements of the adjusting member due to deformation forces cannot result in the tilting of the lower surface of the shoe member. With this arrangement, no tilting forces are transmitted from the cam surface of the adjusting member to the top end of the upwardly extending member.
[0009] In order to secure the shoe member in a very simple manner against tilting movements, the upwardly extending member extends through two guide bearings spaced apart in the planer casing. If two such guide bearings are provided, the biasing means, which biases the shoe member into the raised position, conveniently is arranged at a location intermediate the guide bearings. In that case the biasing means is preferably a leaf spring which spring extends through a transverse aperture in the upwardly extending member. In another embodiment the biasing means is a helical spring which surrounds the upwardly extending member, one end of said spring bearing against the lower of said guide bearings, and the other end of said spring bearing against means associated with the upwardly extending member.
[0010] Embodiments of the invention will now be described in greater detail by way of exemple only, with reference to the accompanying drawings, in which:-
Fig. 1 is a partial longitudinal section through a planer, with only the means for adjusting the depth of cut being shown in detail;
Fig. 2 is a section through the planer shown in Fig. 1, certain parts being omitted; and
Fig. 3 corresponds to Fig. 2 and shows a variant embodiment.
[0011] In order to understand the overall construction of a planer of the kind illustrated, reference can be made to European PS 0 048 304A. Only the structure of the planer for adjusting the depth of cut will be explained hereinafter.
[0012] The planer shown in Figs. 1 and 2 has a plastics casing comprising of two half shells 1, 2 which are interconnected in conventional manner by screws (not shown). A planer blade shaft 3 (shown diagrammatically) is disposed in the casing between a shoe 4 and a shoe member 14. Shoe member 14 is adjustable vertically relative to shoe 4 for the purpose of adjusting the depth of cut.
[0013] The shoe member 14 has a pin-shaped member 15 moulded thereon. A cylindrical portion 16 of member 15 is located in the zone adjacent the shoe member 14. Member 15 is provided also with a rounded top end 18 and adjacent thereto, a cylindrical portion 17. The member 15 extends through a pair of guide bearings 6 and 8 which are arranged in horizontal wall zones 5 and 7 respectively of the casing shell 1. With member 15 so located, the cylindrical portion 17 lies in the zone of the guide bearing 6 and the cylindrical portion 16 lies in the zone of the guide bearing 8. The casing shell 2 presents a horizontal transverse wall 26 which with wall zone 7 of casing shell 1 supports the bearing 8 in the asembled condition of the casing shells 1 and 2.
[0014] A leaf spring 23 is inserted through a recess in the member 15 at a location intermediate the cylindrical portions 16 and 17. One end of spring 23 bears against a curved upper surface 13 of a rib 12, which rib 12 forms part of the casing shell 2. The other end of spring 23 bears against a curved surface 11 of a slider element 10, which element 10 is inserted into the casing shell 1. With this arrangement the spring 23 biases the member 15 and therefore the shoe member 14 upwardly until the shoe member 14 bears against four projections 24 of the casing shells 1 and 2. In this way member 14 is thereby retained in a well-defined upper position. The upper surface of the shoe member 14 is formed with a projection 25 which extends into an aperture in the transverse wall 7. In this manner projection 25 secures the shoe member 14 and the member 15 against rotation. The shoe member 14 may readily be demounted by drawing the slider element 10 out of the casing shell 1 and removing the leaf spring 23.
[0015] A rotary knob 19 is retained in the upper wall 1' of the casing shell 1. The rotary knob 19 is provided with an axial person 20 and a cylindrical surface 21 of relatively large diameter formed on the axial portion 20. The cylindrical surface 21 is disposed in a cylindrical recess bound by the wall portion 9. This arrangement secures the rotary knob 19 and the axial portion 20 against displacement in the direction of the longitudinal axis of the axial portion 20. This construction substantially corresponds to the construction for the retention of the rotary knob in the planer disclosed in European PS 0 048 304A. A substantially circular cam surface 22 is formed at the lower end of the axial portion 20. In the position illustrated in Fig. 1 the cam surface is in fact in engagement with the upper end 18 of the member 15. As shown in Fig. 1 the member 15 is not displaced downwards by cam surface 22 against the bias of the spring 23. Without such a displacement, the upper surface of the shoe member 14 continues to engage the projections 24.
[0016] Upon rotation of the rotary knob 19, the cam surface 21 is rotated. This rotation displaces the cam surface 21 in relation to the upper end 18 of the member 15. In consequence the member 15 is moved downwardly against the bias of the spring 23 (Figs. 1 and 2). During this downward movement the member 15 is guided by the guide bearings 6 and 8. This guidance avoids any tilting of the member 15 and shoe member 14. Consequently, the lower surface of the shoe member 14, which is also moved downwards by the downward movement of the member 15, is also displaced in parallel. Thus, the lower surface of shoe member 14 retains its alignment in relation to the lower surface of the shoe 4. At the same time, the upper end 18 of the member 15 is always biased by the spring 23 against the cam surface 22. This ensures that the lower surface of the shoe member 14 is arranged in a vertical position in relation to the planer blade shaft 3, which vertical position is determined by the rotary position of the cam surface 22.
[0017] The power planer illustrated in Fig. 3 substantially corresponds to that shown in Figs. 1 and 2, like members having like references plus 100.
[0018] The planer illustrated in Fig. 3 differs from that shown in Figs. 1 and 2 merely by the form of spring 123 engaging with the upwardly extending member 115. In the embodiment illustrated in Fig. 3, the spring 123 is diagrammatically indicated as a helical spring. One end of spring 123 bears on the upper surface of a guide bearing 108. The other end of spring 123 bears against a disc 127, which disc 127 is attached to the member 115. This arrangement always retains the upper end 118 of the member 115 in contact with the cam surface used for adjusting the position of the shoe member 114, and hence the depth of cut.
1. A portable power planer with depth of cut adjustment, comprising a casing (1,2),
a shoe (4), a planer blade shaft (3), a shoe member (14) disposed adjacent the shaft
(3), and adjustable vertically with respect to the shoe (4), biasing means (23) urging
the shoe member (14) into a raised position, an adjusting member (19) mounted on the
casing (1,2), an upwardly extending member (15) arranged on said shoe member (14)
and co-operating with said adjusting member (19) for adjusting said depth of cut,
wherein the adjusting member (19, 20, 21) defines a cam surface (22), and the upwardly
extending member (15) has a top end (18) co-operating with said cam surface (22).
2. A planer as claimed in Claim 1, wherein the cam surface (22) is circular.
3. A planer as claimed in either claim 1 or claim 2, wherein the member (15) extends
through two guide bearings (6, 8) space apart in the planer casing (1, 2).
4. A planer as claimed in Claim 3, wherein the biasing means (23, 123) is arranged
at a location intermediate the guide bearings (6, 8, 106, 108).
5. A planer as claimed in Claim 4, wherein the biasing means (23, 123) comprises a
leaf spring (23), which spring (23) extends through a transverse aperture in the upwardly
extending member (15).
6. A planer as claimed in iclaim 5, wherein said leaf spring (23) bears at one end
thereof against a stationary rib (12) and bears at the other end thereof against a
slider element (10), said slider element (10) being adapted to be drawn out of the
planer casing (1, 2).
7. A planer as claimed in Claim 4, wherein the biasing means (23, 123) comprises a
helical spring (123) which surrounds the upwardly extending member (115), one end
of said spring (123) bearing against the lower of said guide bearings (108) and the
other end of said spring (123) bearing against means (127) associated with the upwardly
extending member (115).