CA2398738A1 - Extendable arm - Google Patents

Abstract

An extendable arm has a first arm portion and a second arm portion slideably mounted in the first arm portion for extension and retraction relative thereto to extend and contract the arm. A fluid pressure operated extandable and contractible piston and cylinder device is connected to the first arm portion and to the second arm portion whereby extension of the piston and cylinder device extends the second arm portion relative to the first arm portion and vice versa. A third arm portion is extendable and contractible relative to the second arm portion, and a flexible elongated pulling element has opposite ends connected to the first arm portion and passes around at least one guide on the second arm portion. The flexible pulling element is also secured to the third arm portion, whereby extension and contraction of piston and cylinder device causes extending and retracting movement of the second arm portion relative to the first arm portion and such movement also causes similar movement of the third arm portion relative to the second arm portion.

Description

EXTENDAB1,E ARM
FIE:I_D OF INVENTION
(0001 ] This invention relates to extendable arms.
BACKGROUND OF INVENTION

[0002) Extendable anus are useful for various purposes. An extenable arm is suitable for use in a fruit catcher as described in U.S. patent 6,052,981 (Pavonc). 7"he extendable arm described in the Pavone patent is operated by rotation of a spool. Although this arrangement works well, it is not particularly fast in opevation.

(0003] It is therefore an object of the present im~ention to provide an extendable armwhich is more quickly extended and contracted.
SUMMARY OF INVENTION

[0004) According to the invention, an extendable arm has a first arm portion, a second arm portion slideably mounted in the first am portion for e:Ktcnsion and retraction relative thereto to extend and contract the amp, a fluid pressure operated extendable and contract able piston and cylinder device connected to the first arm portion and to the second arm portion whereby extension of the piston and cylinder device extends the second arm portion relative to the first arn~ portion acrd vice versa, a third arm portion extendable and contractable relative to the second ann portion, and a flexible elongated pulling element having opposite ends connected to the first arm portion and passing around at least one guide on the second arm portion, said flexible pulling element also being secured to the third arm portion, whereby extension and contraction of piston and cylinder device causes extending and retractins; movement of the second arn~ portion relative to the first arm portion and such movement also causes similar movement of the third arm portion relative to the second arm portion.

[0005] The extendable ann may also have a fourth ann portion secured to the first ann portion, a fifth arm postion slidcably mounted in the fourth arm portion for extension and retraction relative thereto, a sixth arm portion indentablf; and retractable relative to the fifth ann portion, and a second flexible elongated pullinf; element having opposite ends connected to the fourth ann portion and passing around at least one guide on the fifth arn~
portion, said second pulling element also being secured to the sixth ann portion.
whereby extension and retraction of the pistol cylinder device also causes extending and retracting movement of the fifth ar-m portion relative to the fourth ann portion and said movement also causes similar movement of the sixth arm portion relative to the fifth ann portion.
DESC'RIP'TION OF TI-iE DRAWINGS

[0006] Embodiments of the lllvetlOtl wlll now be described, by way of example only, with reference to the accompanying drawings, of which:

[0007] Fig. l is a front view ofan extendable arn1 in the contracted condition in accordance with one embodiment of tire invention, [0008] Fig.2 is a rear view of the arm of Fig.l, )0009] Fig.3 is a diagramatic view showing the flexible holing element arrangement, in the contracted condition, [0010] Fig.4 is a front view of the extendable arm in an extended condition, [0011 ) Fig.S is a rear view of the arm of Fig.4, [0012] Fig.6 is a diagramatic view showing the flexible holing; clement arrangement, in the extended condition, [0013) Fig.7 is a front view of an extendable arm in the contracted condition in accordance with a second embodiment of the invention, and [0014] Fig.8 is a rear view of the arn~ of Fig.7 in an extended condition.
I:)ESC'R1P'I~ION OF PREFERRED EME30DIMEN'I~S
(0015] Referring first to Figs.l to 6 of the accompanying drawings, an extendable arm in accordance with one embodiment of the invention has a laterally spaced pair of hallow rear arn~ portions 10, 12 of rectangular section. The rear arm portions 10, 1:? aresecured in laterally spaced relationship by a rear cross member 14 and a front cross member 16 bolted at opposite ends to the rear arm portions 10, 12. A hydraulically operated extendable and contractible piston and cylinder device has the rear end of its cylinder I 8 bolted to the rear cross member I 6 and the front end of its cylinder 18 bolted to the front cross memberl (>.
[0016] A pair of intermediate arm portions 20, 22 of similar construction to the rear arn~ portions 10, 12 are slidcably mounted therein and are secured at their front ends by a further cross member 24 to which the front end of the 1)lSt0I1 26 of the piston and cylinder device is secured. A pair of further arm portions 28, 30 of channf;l section are slideibly mounted in the intermediate inn portions 20, 22 respectively.
_3_ (0017[ A first wire 32 has opposite ends secured to an anchor block 34 secured to tl°ie front end of the rear ann portion 10. From the anchor block 34, they first wire 32 passes around a rotatable pulley 3(i mounted in the rear end of the intec-mediate ann portion 10, and then extends forwardly through ate anchor block 38 mounted in the rear end of the front end portion 28. The wire 32 is secured to the anchor blocb; 38 in a suitable manner, for example by a grub screw (not shown). The wire 32 then extends fonvardly from the anchor block 38 and passes around a rotatable pulley 40 mounted at the front end of the intermediate arn~ portion 20 to then extend rearwardly back to the anchor block 34.
[0018] A second wire 33 is connected in a similar manner to the rear arm portion 12, intern~ediate ann portion 22 and front arm portion 30. For ease of illustration, like reference numerals are used for like items.
[0019] Figs.l to 3 show the extendable arm in its contracted condition. When hydraulic fluid under pressure is applied to the piston and cylinder device 18, 26 in an extending sense, the piston rod 26 moves to the cxteded position shown in Figs.4 to 6. And thereby move the intennediatv arn~ portion 20, 22 to their extended positions relative to the rear ann portions 10, 12. At the same time, the wires 32, 33 also cause the front arm portions 28, 30 to be moved to their extended positions relative to th~~ intermediate arm portions 20, 22.
[0020] Contraction of the extendable arn~ back to the contracted condition is effected by reversing the fluid pressure to the piston and cylinder device 18, 20 to cause contraction thereof so that the intermediate arm portions 20, 22 retract into the rear ann portions 10, 12 and the front end portions 28, 30 refract into the intermediate arm portions 20, 22.
[0021 ] A second embodiment of the invention is shown in Figs.7 and 8. This embodiment it in fact omits the rear arm portion 12 intermediate arn~ portion 22 and front end portion 30, wire 33 and related components of the embodiment shown in Figs.l to 6. The cross members 14, l6 and 24 are replaced by shorter cross members 15, 17 and 25. The operation of this embodiment will be readily apparent from the foregoing description of the previous embodiment.
(0022] Further embodiments of the invention will also now be readily apparent to a person skilled in the art, the scope of the invention being defined in the appended claims.

Claims (2)

1. An extendable arm having a first arm portion, a second arm portion slideably mounted in the first arm portion for extension and retraction relative thereto to extend and contract the arm, a fluid pressure operated extandable and contractible piston and cylinder device connected to the first arm portion and to the second arm portion whereby extension of the piston and cylinder device extends the second arm portion relative to the first arm portion and vice versa, a third arm portion extendable and contractible relative to the second arm portion, and a flexible elongated pulling element having opposite ends connected to the first arm portion and passing around at least one guide on the second arm portion, said flexible pulling element also being secured to the third arm portion, whereby extension and contraction of piston and cylinder device causes extending and retracting movement of the second arm portion relative to the first arm portion and such movement also causes similar movement of the third arm portion relative to the second arm portion.

2. An extendable arm according to claim 1 also having a fourth arm portion secured to the first arm portion, a fifth arm postion slideably mounted in the fourth arm portion for extension and retraction relative thereto, a sixth arm portion indentable and retractable relative to the fifth arm portion, and a second flexible elongated pulling element having opposite ends connected to the fourth arm portion and passing around at least one guide on the fifth arm portion, said second pulling element also being secured to the sixth arm portion.

whereby extension and retraction of the piston cylinder device also causes extending and retracting movement of the fifth arm portion relative to the fourth arm portion and said movement also causes similar movement of the sixth inn -portion relative to the fifth inn portion