EP1882525A2

EP1882525A2 - Caulking gun

Info

Publication number: EP1882525A2
Application number: EP07252739A
Authority: EP
Inventors: Jiada c/o Positec Power Tools Wang (Suzhou) Co Ltd; Wenlai c/o Positec Power Tools Gu (Suzhou) Co Ltd; Qiang c/o Positec Power Tools Lu (Suzhou) Co Ltd; Gianni Borinato
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2006-07-24
Filing date: 2007-07-09
Publication date: 2008-01-30
Also published as: EP1882525A3

Abstract

The present invention relates to a caulking gun apparatus comprising an elongate housing (1) for holding a cartridge (6) in a dispensing position, a piston rod (2) for engaging the cartridge for dispensing the caulking material and at least one driving lever (3) in slideable engagement with the piston rod. The apparatus further comprises a motor (4) means which is disposed within the elongate housing and coupled to a motor shaft (4') and a transmission mechanism such that during rotation of the rotary motor shaft, power is transmitted from the rotary motor to the piston rod. The apparatus further comprises a mechanical mechanism (7) for operating the piston rod when the rotary motor is disabled.

Description

The invention relates to an apparatus (eg a caulking gun) for dispensing caulking material, more particularly relates to a caulking gun which has a manual control mode and an automatic control mode.
Generally speaking, caulking guns are designed primarily for dispensing caulking material packaged in a cylindrical container or cartridge. The cartridge has a dispensing nozzle at one end from which caulking material can be forcibly discharged during a caulking operation. The caulking material is dispensed from the dispensing nozzle by advancing a movable wall disposed within the cartridge towards the nozzle end.
Conventionally a hsuad-held caulking gun uses a piston type member (eg a piston) driven by a shaft to push the movable wall (as for example disclosed in US-A-6119903 and US-A-4264421 ). The piston member and the shaft may be driven manually but this often causes hand fatigue and therefore limits the efficiency of the caulking operation. Furthermore, variations in the level of hand strength and gripping capability may mean that the operator applies an inconsistent force which creates a non-uniform (intermittent) flow of caulking material.
Conventional electric caulking guns use a rotary motor (such as a DC motor) in combination with a piston and a shaft configured to apply force to the movable wall when a user activates the rotary motor. Electric caulking guns are configured with a transmission linkage that converts motor rotational to linear piston motion. Certain transmission linkages are designed to provide torque reduction to the rotary motor so that motor size and therefore electrical energy consumption may be reduced. Unfortunately such conventional transmission linkages are typically complex and reduce power transmission between the rotary motor rotation and the piston.
One type of transmission linkage is a screw-type linkage in which a piston is rotatably coupled to a long screw at one end and to the rotary motor at the other end. While the screw provides a uniform caulking force when rotated, it requires a large motor as little (if any) torque reduction may be derived. Conventional gears are often used to provide torque reduction. Unfortunately, gears add complexity and reduce power transmission between the rotary motor and piston. Moreover, a screw-type linkage and gears increase the complexity of the part of the apparatus dedicated to accommodating the retraction of the piston for cartridge replacement.
A transmission mechanism disclosed in US4615469 comprises a gear and a piston rod with a sawtooth portion. A transmission mechanism disclosed in US7063240 comprises two cams to advance a piston. Unfortunately, this device has too many parts. It is expensive and complex to make and has a large volume and weight.
The present invention seeks to improve the efficiency of a caulking gun by providing manual and automatic control.
Thus viewed from one aspect the present invention provides an apparatus for dispensing caulking material from a cartridge comprising:

a) an elongate housing for supporting the cartridge in a dispensing position at or near to its distal end;
b) a piston rod extending substantially axially in the elongate housing substantially from or near to its proximal end to its distal end;
c) a rotary motor positioned at or near to the proximal end of the housing;
d) a rotary motor shaft driven by the motor;
e) a transmission mechanism coupled to or mounted on the rotary motor shaft so as to transmit power consistently from the rotary motor to the piston rod whereby the piston rod actuates the cartridge to dispense the caulking material; and
f) a mechanical trigger mechanism for causing the piston rod to actuate the cartridge to dispense the caulking material when the rotary motor is disabled.

The present invention advantageously constitutes a simple inexpensive arrangement of small volume and weight that is versatile in dispensing caulking material intermittently (eg in manual mode) or consistently stepwise (eg in automatic mode).
Preferably the mechanical trigger mechanism comprises:

a trigger pivotally mounted in the housing. The trigger may be pivotally mounted on the housing by a lateral pin. The trigger mechanism may further comprise an intermediate lever engaging the trigger.

The transmission mechanism may comprise a cam, gear or rack coupled to or mounted on the rotary mounting shaft.
In a preferred embodiment, the transmission mechanism comprises:

a single cam mounted on or coupled to the rotary motor shaft, wherein a distal radial cam face of the cam is uneven and includes an anterograde surface and a retrograde surface; and
one or more driving levers in slideable engagement with the piston rod, wherein the distal radial cam face engages the one or more driving levers and the anterograde surface and the retrograde surface are arranged such that during rotation of the rotary motor shaft, power is transmitted from the rotary motor to the piston rod continuously by the anterograde surface.

Preferably the one or more levers are a single lever.
The axis of the cam may be substantially parallel to the axis of the housing. The axis of the cam may be substantially parallel to the axis of the piston rod.
Preferably the retrograde surface is arranged substantially parallel with respect to the axis of the rotary motor shaft. The anterograde surface may be a lifting surface.
Preferably the transmission mechanism further comprises:

an active rod rotationally coupled axially to the rotary motor shaft, wherein the cam is radially mounted on the active rod.

Preferably the retrograde surface is substantially parallel to the axis of the rotary motor shaft. Particularly preferably the retrograde surface is a steep step (eg substantially parallel to the axis of the rotary motor shaft) or a progressively descendant step (eg divergent from the axis of the rotary motor shaft).
In a preferred embodiment, a first driving lever and a second driving lever are in slidable engagement with the piston rod and the uneven distal radial cam surface engages the first and second driving lever.
The first and second driving lever may be disposed above, below, to the right or to the left of the active rod
Particularly preferably the first and second driving levers engage the cam at a first and second contact point respectively. The phase difference between the first and second contact point may be in the range 120 to 240 degrees. Preferably the first and second contact points are separated by about 210 degrees with respect to the axis of the rotary motor shaft.
Preferably the first and second driving levers include a wheel which engages the uneven distal radial cam surface of the cam.
Preferably a first and second handspike are disposed between the cam and the first and second driving lever, The first and second handspikes may be mounted in a guide portion of the housing.
In a particularly preferred embodiment, the transmission mechanism comprises:

a single driving lever in slideable engagement with the piston rod;
a gear coupled to the rotary motor shaft; and
a step drive member engaging the single driving lever such that during rotation of the rotary motor shaft, power is transmitted from the rotary motor to the piston rod consistently stepwise by the step drive member.

Preferably the housing comprises:

a first housing detachably coupled to a second housing, wherein the piston rod and driving lever are disposed in the first housing and the rotary motor, gear and step drive member are disposed within the second housing.

Preferably the second housing is coupled to the first housing in at least two positions whereby the transmission mechanism drives the driving lever in different paths. The first housing and second housing may be attached by insertion or using clips.
Preferably the step drive member comprises a reciprocative member eccentrically coupled to or mounted on the gear, wherein the reciprocative member engages the driving lever. The axis of the reciprocative member may be substantially parallel to the axis of the housing. The axis of the reciprocative member may be substantially parallel to the axis of the piston rod.
Preferably the reciprocative member is a reciprocating rod with a slot, wherein a pin is eccentrically disposed on the gear and a first end of the pin is positioned in the slot.
Alternatively preferably the step drive member comprises a cam fixed to the gear, wherein the cam engages the driving lever. The axis of the cam may be substantially perpendicular to the axis of the housing. The axis of the cam may be substantially perpendicular to the axis of the piston rod.
Further alternatively preferably the step drive member comprises a sectorial gear coupled to or mounted on the gear and a rack coupled to or mounted on the sectorial gear, wherein the rack engages the driving lever.
Preferably the lever has an aperture for receiving the piston rod. The piston rod and aperture are complementarily shaped and may be circular, square or hexagonal.
Preferably the housing further comprises:

at least two side walls for slidably supporting the piston rod. The side walls may be at intermediate axial positions internally in the housing. The piston rod may traverse the first supporting wall and the second supporting wall so as to be movably disposed substantially axially in the elongate housing.

In a preferred embodiment, the driving lever is positioned between an adjacent two of the at least two side walls and a restoring member couples a distal face of the driving lever and a proximal face of one of the at least two side walls.
Preferably the apparatus further comprises:

one or more driving levers capable of engaging the piston rod, wherein in use the transmission mechanism effects a cycle of progressive engagement and disengagement between the one or more driving levers and the piston rod so as to transmit power consistently from the rotary motor to the piston rod.

Particularly preferably the trigger mechanism is capable of urging directly or indirectly the one or more driving levers into enagement with the piston rod.
The rotary motor may be powered by an AC power source or a battery.
The present invention will now be described in a non-limitative sense with reference to the accompanying drawings in which

Figure 1 is a sectional view of a first embodiment of the invention in which a driving lever is in a release position with a cam;
Figure 2 is a sectional view of the first embodiment of the invention in which the driving lever is in an engagement position with the cam;
Figure 3 is a side elevational view of the first embodiment of the invention in which the driving lever is in a release position with the piston rod;
Figure 4 is a side elevational view of the first embodiment of the invention in which the driving lever is in an engagement position with the piston rod;
Figure 5 is a perspective view of the cam of the first embodiment;
Figure 6 is a perspective view of an alternative cam;
Figure 7 is a sectional view of a second embodiment of the invention in which twin driving levers are in a release position with a cam;
Figure 8 is a sectional view of the second embodiment of the invention in which the twin driving levers are in an engagement position with the cam;
Figure 8a is a front view of the cam of Figure 8;
Figure 9 is a side elevational view of the second embodiment in which the second driving lever is in an engagement position with the piston rod;
Figure 10 is a side elevational view of the second embodiment of the invention in which the first driving lever is in an engagement position with the piston rod;
Figure 11 is a sectional view of a third embodiment of the invention;
Figure 12 is a sectional view of a fourth embodiment of the invention;
Figure 13 is a sectional view of a fifth embodiment of the invention;
Figure 14 is a partial sectional top view of Figure 13;
Figure 15 is a side elevational view illustrating a sixth embodiment of the invention in which the driving lever is in an engagement position with the piston rod;
Figure 16 is a side elevational view illustrating the sixth embodiment of the invention in which the driving lever is in a release position with the piston rod;
Figure 17 is a side elevational view illustrating a seventh embodiment of the invention in which the driving lever is in an engagement position with the piston rod; and
Figure 18 is a side elevational view illustrating the seventh embodiment of the invention in which the driving lever is in a release position with the piston rod.

With respect to Figure 1, an embodiment of the caulking gun of the invention has an elongate housing 1 which supports a cartridge 6 from which is dispensed caulking material 61. A distal end of the cartridge 6 abuts an inner distal wall 14 of the caulking gun so that a nozzle 62 disposed at the distal end of the cartridge 6 extends freely through and beyond the distal wall 14.
The elongate housing 1 has at consecutive intermediate positions a first supporting wall 11 and a second supporting wall 12. A piston rod 2 traverses the first supporting wall 11 and the second supporting wall 12 and is movably disposed substantially axially in the elongate housing 1. A single driving lever 3 is provided with an aperture 31 to permit it to be slidably mounted on the piston rod 2 between the first supporting wall 11 and second supporting wall 12. A piston 21 is fixed to the distal end of the piston rod 2 and abuts a movable wall 600 at a proximal end of the cartridge 6. The caulking material 61 is discharged from the nozzle 62 when the movable wall 600 is advanced by the piston 21,
The caulking gun includes a rotary motor 4 positioned at a proximal end of the elongate housing 1 and coupled to a substantially axially extending rotary motor shaft 41. The rotary motor 4 is electrically connected to a battery 16 disposed in a substantially central lower portion of the elongate housing 1. An electrical switch 42 is set in the elongate housing I to electrically connect the rotary motor 4 and the battery 16. An active rod 9 is connected axially to the rotary motor shaft 41 by splines and is rotatable with the rotary motor shaft 41. ..
A cam 5 is mounted radially on and is rotational with the active rod 9, The cam 5 has a distal radial cam surface that is uneven and in slidable engagement with a lower part of the proximal face of the driving lever 3. When a non-continuous force is applied to the lower part of the proximal face of the driving lever 3 by the cam 5, the driving lever 3 can pivot into engagement with the piston rod 2 at an engagement position 32. When a continuous force is applied to the lower part of the proximal face of the driving lever 3 by the cam 5, the driving lever 3 can move with the piston rod 2.
As illustrated in Figure 5, the distal radial cam face of the cam 5 includes an anterograde surface 51 and a retrograde surface 52. The anterograde surface 51 extends over about 360 degrees and the retrograde surface 52 is a steep step substantially parallel to the axis of the rotary motor shaft 41.
With reference to Figure 1, the caulking gun further comprises a mechanical trigger mechanism 7 that includes a trigger 71 and a lever 72. The trigger 71 is depressed and rotates about a pin 721 and in an operational position engages the first end 722 of the lever 72 whilst the second end 723 of the lever 72 engages the proximal radial face of the cam 5. The mechanical trigger mechanism 7 further comprises a lock member 73 and a spring 74, The lock member 73 can be selectively locked to the piston rod 2 by a switch (not shown).
With reference to Figure 2, the lock member 73 releases the piston rod 2 when the switch is in automatic control mode and the piston rod 2 is retractable in the elongate housing 1. When the switch is in automatic control mode, the electrical switch 42 is switched on to connect electrically the rotary motor 4 and the battery 16. The trigger 71 is depressed and rotates about the pin 711 to engage the first end 722 of the lever 72 in an operational position whilst the second end 723 of the lever 72 engages the cam 5. The rotary motor 4 rotates the rotary motor shaft 41 and the active rod 9. As the cam 5 rotates, the driving lever 3 consistently engages the distal radial cam face alternately at the anterograde surface 51 and the retrograde surface 52. As the anterograde surface 51 continuously engages the driving lever 3 (see Figures 3 and 4), it advances the driving lever 3 and the piston rod 2 in direction E so that the piston 21 compresses caulking material 61 out of the nozzle 62. When the retrograde surface 52 engages the driving lever 3, the driving lever 3 is restored to the position shown in Figure 3 by the restoring spring 8 until the anterograde surface 51 engages the driving lever 3 again. Because the time between disengaging and re-engaging the anterograde surface 51 is short, the caulking material 61 is effectively dispensed continuously.
The lock member 73 (see broken lines in Figure 2) is locked to the piston rod 2 when the switch is in manual control mode and the piston rod 2 is non-retractable in the elongate housing 1. When the trigger 71 is depressed, the trigger 71 rotates about the pin 721 and engages the first end 722 of the lever 72 in an operational position whilst the second end 723 of the lever 72 engages and moves the cam 5. The caulking material 61 can be dispensed from the cartridge 6 intermittently by depressing and releasing the trigger 71.
With reference to a second embodiment illustrated in Figure 7, the difference from the first embodiment of the present invention is that the elongate housing 1 has a first supporting wall 11. a second supporting wall 12 and a third supporting wall 13 at consecutive intermediate positions. A first driving lever 3 a and a second driving lever 3b have an aperture 31a, 31b respectively to permit them to be slidably mounted on the piston rod 2. The second driving lever 3b is longer than the first driving lever 3a and has a proximal end face 33b slidably engaged with the distal radial cam surface of the cam 5, The first driving lever 3a and a first restoring spring 8a are disposed between the first supporting wall 11 and the second supporting wall 12. The second driving lever 3b and a second restoring spring 8b are disposed between the second supporting wall 12 and the third supporting wall 13.
With reference to Figure 8, the uneven distal radial cam face of cam 5 is in slidable engagement with the first and second driving levers 3a, 3b to consistently advance piston rod 2. The first and second driving levers 3a, 3b engage the cam 5 at first and second contact points 91 and 92 respectively (see Figure 8a). The first and second contact points 91, 92 are separated by 210 degrees (P) with respect to the axis of the rotary motor shaft 41.
When the cam 5 drives a lower end of the proximal face of the first driving lever 3a and the proximal end face 33b of the second driving lever 3b, the first and second driving levers 3a, 3b pivot into engagement with the piston rod 2 at respective engagement positions 32a, 32b.
The retrograde surface 52 of the cam 5 is in the form of a step (as in the first embodiment) but with a descendent face portion (A) shown in Figure 6 which is angled with respect to the axis of the active rod 9.
When the switch of the caulking gun is in automatic control mode, the trigger 71 is depressed and the electrical switch 42 is switched on to connect electrically the rotary motor 4 and the battery 16. As shown in Figure 8, the trigger 71 rotates about the pin 721 and engages the first end 722 of the lever 72 in an operational position whilst the second end 723 of the lever 72 engages the cam 5. The cam 5 engages the first and second driving levers 3a, 3b and the first and second driving levers 3a, 3b engage the piston rod 2 alternately (ie when a first of the driving levers 3a, 3b is not in engagement with the piston rod 2, the other of the driving levers 3a, 3b is in engagement with the piston rod 2). The rotary motor 4 rotates the rotary motor shaft 41 and the active rod 9. As the cam 5 rotates, the driving levers 3a, 3b consistently engage the distal radial cam face alternately at the anterograde surface 51 and the retrograde surface 52. As the anterograde surface 51 continuously engages the first driving lever 3a (see Figure 9), the anterograde surface 51 has already engaged the second driving lever 3b for a period of time and moved the second driving lever 3b and piston rod 2 in the direction F. As the anterograde surface 51 continuously engages the second driving lever 3b (see Figure 10), the anterograde surface 51 has already engaged the first driving lever 3a for a period of time and moved the first driving lever 3a and the piston rod 2 in direction F.
When the switch of the caulking gun is in manual control mode, the lock member 73 is positioned according to the broken lines in Figure 8. When the trigger 71 is depressed, the trigger 71 rotates about the pin 721 and engages a first end 722 of the lever 72 in an operational position whereas the second end 723 of the lever 72 engages and moves the cam 5. The caulking material 61 is dispensed from the cartridge 6 intermittently by depressing or releasing the trigger 71.
In a third embodiment of the present invention illustrated in Figure 11, each of a first and second driving lever 3a, 3b has a wheel 34a, 34b which engages the uneven distal radial cam surface of the cam 5. The cam 5 is in rolling engagement with the wheel 34a, 34b and the friction is relatively low so that the working life of the caulking gun is prolonged. The automatic and manual operation is the same as in the second embodiment.
In a fourth embodiment of the present invention illustrated in Figure 12, a handspike 35a, 35b is provided between the cam 5 and the first and second driving lever 3a, 3b. The handspike 35a, 35b is in slidable engagement with a guide sleeve 36 which is fixed to the elongate housing 1. A first end of the first handspike 35a abuts the uneven distal radial cam surface of the cam 5 whilst a second end of the first handspike 35a abuts the first driving lever 3a, A first end of the second handspike 35b abuts the uneven distal radial cam surface of the cam 5 whilst a second end of the second handspike 35b abuts the second driving lever 3b. The automatic and manual operation is the same as in the second embodiment. Because the handspike 35a, 35b and driving lever 3a, 3b constitute a simple rod construction, the caulking gun is convenient to use and cheap to manufacture.
A fifth embodiment of the present invention is shown in Figure 13. A first module comprises a first housing 101 and parts disposed in the first housing 101. A second module (shown in broken lines) comprises a second housing 102 and parts disposed in the second housing 102. The elongate housing 1 comprises the first housing 101 detachably coupled to the second housing 102. The piston rod 2 and the driving lever 3 are disposed within the first housing 101. The battery 16, the rotary motor 4, an electrical switch 42, a journey switch 22, a gear 53 and a step drive member 54 are disposed within the second housing 102.
Further referring to Figure 14, the step drive member 54 is a horizontally reciprocative rod. It is disposed eccentrically to gear 53 and coupled to the rotary motor shaft 41. A slot 541 is disposed within the reciprocative rod 54. A pin 531 is eccentrically disposed on the gear 53 and an end of the pin 531 is positioned in the slot 541. During rotation of the rotary motor shaft 41, rotation of gear 53 is transmitted into reciprocating movement of the reciprocative rod 54.
According to Figure 13, the driving lever 3 and a restoring spring 8 are disposed between the first supporting wall 11 and the second supporting wall 12. The piston rod 2 is configured to engage the cartridge 6 for dispensing the caulking material 61 and the driving lever 3 has an aperture 31 for mounting radially on the piston rod 2. When a force is applied to a lower proximal face of the driving lever 3, the driving lever 3 pivots into engagement with the piston rod 2 and then advances together with the piston rod 2.
The trigger 71 rotates about a pin 711 on the first housing 101 and an upper part of the trigger 71 engages the lower proximal face of the driving level 3. A restoring spring is disposed external to the housing 1 on a lower part of trigger 71 for biasing the trigger 71 back to the non-depressed position. When the trigger 71 is manually depressed, the driving lever 3 moves the piston rod 2 along the cartridge 6. When the trigger 71 is released, the driving lever 3 is retracted by the restoring spring 8. A clip spring 81 is disposed between the piston rod 2 and the first housing 101 so that the piston rod 2 will not retract by virtue of the frictional force between the clip spring 81 and the piston rod 2. When the trigger 71 is depressed and released, the caulking material 61 is dispensed intermittently from the nozzle 62.
If the first module is fixed to the second module, the caulking gun is in an automatic operation mode. When the operator depresses the electrical switch 42, the rotary motor 4 and the battery 16 are connected. The rotary motor shaft 41 drives the gear 53 rotationally and the reciprocating rod 54 reciprocates. As shown in Figure 13, when the reciprocating rod 54 moves in direction B, it pivots the driving lever 3 to engage the piston rod 2. When the reciprocating rod 54 moves continuously in direction B, it moves the driving lever 3 and the piston rod 2 against the restoring spring 8. Thus the caulking material 61 is dispensed from the nozzle 62.
When reciprocating rod 54 moves in a direction opposite to B, the driving lever 3 pivots reversely under the force of the restoring spring 8 and disengages the piston rod 2. Due to the frictional force between the clip spring 81 and the piston rod 2, the piston rod 2 will not move with the driving lever 3. The reciprocation is cyclical causing the piston rod 2 to advance consistently and the caulking material 61 to be discharged continuously from the nozzle 62.
The journey switch 22 is disposed in the second housing 102 and is connected to the rotary motor 4 via wires (not shown in the Figures). When the journey switch 22 is depressed by the piston rod 2, it breaks the electrical connection between the rotary motor 4 and battery 16. The type of journey switch 22 is selected according to the length of the cartridge 6.
When the electrical power is off, the caulking gun is operable manually. The second module could be removed to reduce the weight of the caulking gun.
The second housing 102 is coupled to the first housing 101 in a plurality of positions. The reciprocative rod 54 engages the driving lever 3 at different parts and drives the driving lever 3 at different angles so that the caulking gun has different discharge speeds for discharging caulking material.
With reference to Figures 15 and 16, in the sixth embodiment of the invention, the step drive member comprises a gear 53 and a cam 54a which is fixed to the gear 53. The cam 54a drives the driving lever 3. When the operator depresses the electrical switch 42, the rotary motor 4 and battery 16 are connected. The rotary motor shaft 41 drives the gear 53 rotationally which rotates the cam 54a. The cam 54a has a proximal end 56 and a distal end 57. When the cam 54a rotates from the proximal end 56 to the distal end 57, it pivots the driving lever 3 into engagement with the piston rod 2. When the cam 54a moves continuously in direction B, it advances the driving lever 3 and the piston rod 2 against the restoring spring 8. Thus, the caulking material 61 is dispensed from the nozzle 62.
When the cam 54a rotates from the distal end 57 to the proximal end 56, the driving lever 3 pivots reversely under the force of the restoring spring 8 and disengages the piston rod 2. Because of the frictional force between the clip spring 81 and the piston rod 2, the piston rod 2 will not move along the direction B' together with the driving lever 3 which is restored to its original position. The reciprocation is cyclical and the piston rod 2 advances consistently and the caulking material 61 is dispensed continuously from the nozzle 62.
With reference to Figures 17 and 18, in the seventh embodiment of the invention the step drive member comprises a sectorial gear 54b coupled to a gear 53. The rack 55b is coupled to the sectorial gear 54b and the rack 55b advances the driving lever 3. The sectorial gear 54b is fixed to the rotary motor shaft 41 by a bolt.
When the operator depresses the electrical switch 42, the rotary motor 4 and battery 16 are connected electrically. The rotary motor shaft 41 drives the sectorial gear 54b rotationally in direction A. When the teeth 58 of the sectorial gear 54b engage the rack 55b, the rack 55b moves in direction B and drives the driving lever 3 into engagement with the piston rod 2. When the rack 55b moves continuously in direction B, it advances the driving lever 3 and the piston rod 2 against the restoring spring 8. Thus, the caulking material 61 will be dispensed from the nozzle 62.
When the teeth 58 of the sectorial gear 54b are not in engagement with rack 55b, the driving lever 3 rotates reversely by the force of restoring spring 8 and disengages the piston rod 2. Because of the frictional force between the clip spring 81 and the piston rod 2, the piston rod 2 will not move in direction B' together with the driving lever 3 but the rack 55b will move in direction B'. The reciprocation is cyclical. The piston rod 2 advances stepwise and the caulking material 61 is dispensed from the nozzle 62.

Claims

An apparatus for dispensing caulking material (61) from a cartridge (6) comprising:
a) an elongate housing (1) for supporting the cartridge (6) in a dispensing position at or near to its distal end;

b) a piston rod (2) extending substantially axially in the elongate housing (1) substantially from or near to its proximal end to its distal end;

c) a rotary motor (4) positioned at or near to the proximal end of the housing (1);

d) a rotary motor shaft (41) driven by the motor;

e) a transmission mechanism coupled to or mounted on the rotary motor shaft (41) so as to transmit power consistently from the rotary motor (4) to the piston rod (2) whereby the piston rod (2) actuates the cartridge (6) to dispense the caulking material (61); and

f) a mechanical trigger mechanism (7) for causing the piston rod (2) to actuate the cartridge (6) to dispense the caulking material (61) when the rotary motor (4) is disabled.
An apparatus as claimed in claim 1, wherein the mechanical trigger mechanism (7) comprises:
a trigger (71) pivotally moaned in the housing (1).
An apparatus as claimed in claim 1 or 2, wherein the transmission mechanism comprises :
a single cam (5) mounted on or coupled to the rotary motor shaft (41), wherein a distal radial cam face of the cam (5) is uneven and includes an anterograde surface (51) and a retrograde surface (52); and

one or more driving levers (3,3a,3b) in slideable engagement with the piston rod (2), wherein the distal radial cam face engages the one or more driving levers (3,3a,3b) and the anterograde surface (51) and the retrograde surface (52) are arranged such that during rotation of the rotary motor shaft (41), power is transmitted from the rotary motor (4) to the piston rod (2) continuously by the anterograde surface (51).
An apparatus as claimed in claim 3, wherein the transmission mechanism further comprises:
an active rod (9) rotationally coupled axially to the rotary motor shaft (41), wherein the cam (5) is radially mounted on the active rod (9),
An apparatus as claimed in claim 3, wherein the retrograde surface (52) is substantially parallel to the axis of the rotary motor shaft (41).
An apparatus as claimed in claim 5, wherein the retrograde surface (52) is a steep step or a progressively descendent step.
An apparatus as claimed in claim 3, wherein a first driving lever (3a) and a second driving lever (3b) are in slidable engagement with the piston rod (2) and the uneven distal radial cam surface engages the first and second driving lever (3a, 3b).
An apparatus as claimed in claim 7 wherein the first and second driving levers (3a, 3b) engage the cam (5) at a first and second contact point (91, 92) respectively, wherein the first and second contact point (91, 92) are separated by 210 degrees with respect to the axis of the rotary motor shaft (41).
An apparatus as claimed in claim 7 or 8, wherein the first and second driving levers (3a, 3b) include a wheel (34a, 34b) which engages the uneven distal radial cam surface of the cam (5).
An apparatus as claimed in claim 7 or 8, wherein a first and second handspike (35a, 35b) are disposed between the cam (5) and the first and second driving lever (3a, 3b).
An apparatus as claimed in claim 1 or 2, wherein the transmission mechanism comprises:
a single driving lever (3) in slideable engagement with the piston rod (2);

a gear (53) coupled to the rotary motor shaft (41); and

a step drive member (54, 54a, 54b, 55b) engaging the single driving lever (3) such that during rotation of the rotary motor shaft (41), power is transmitted from the rotary motor (4) to the piston rod (2) consistently stepwise by the step drive member (54, 54a, 54b, 55b).
An apparatus as claimed in claim 11, wherein the housing (1) comprises;
a first housing (101) detachably coupled to a second housing (102), wherein the piston rod (2) and driving lever (3) are disposed in the first housing (101) and the rotary motor (4), gear (53) and step drive member (54, 54a, 54b, 55b) are disposed within the second housing (102).
An apparatus as claimed in claim 12, wherein the second housing (102) is coupled to the first housing (101) in at least two positions whereby the transmission mechanism drives the driving lever (3) in different paths.
An apparatus as claimed in claim 11, wherein the step drive member comprises a reciprocative member (54) eccentrically coupled to or mounted on the gear (53), wherein the reciprocative member (54) engages the driving lever (3).
An apparatus as claimed in claim 14, wherein the reciprocative member (54) is a reciprocating rod with a slot (541), wherein a pin (531) is eccentrically disposed on the gear (53) and a first end of the pin (531) is positioned in the slot (541).
An apparatus as claimed in claim 11, wherein the step drive member comprises a cam (54a) fixed to the gear (53), wherein the cam (54a) engages the driving lever (3),
An apparatus as claimed in claim 11, wherein the step drive member comprises a sectorial gear (54b) coupled to or mounted on the gear (53) and a rack (55b) coupled to or mounted on the sectorial gear (54b), wherein the rack (55b) engages the driving lever (3).
An apparatus as claimed in claim 3 or 11, wherein the lever (3, 3a, 3b) has an aperture (31, 31a, 31b) for receiving the piston rod (2).
An apparatus as claimed in claim 1 wherein the housing (1) further comprises:
at least two side walls (11, 12, 13) for slidably supporting the piston rod (2).
An apparatus as claimed in claim 19, wherein the driving lever (3, 3a, 3b) is positioned between an adjacent two of the at least two side walls (11, 12, 13) and a restoring member (8, 8a, 8b) couples a distal face of the driving lever (3, 3a, 3b) and a proximal face of one of the at least two side walls (11,12,13).
An apparatus as claimed in claim 1 further comprising:
one or more driving levers (3, 3a, 3b) capable of engaging the piston rod (2), wherein in use the transmission mechanism effects a cycle of progressive engagement and disengagement between the one or more driving levers (3, 3a, 3b) and piston rod (2) so as to transmit power consistently from the rotary motor (4) to the piston rod (2).
An apparatus as claimed in claim 21 wherein the trigger mechanism is capable of urging directly or indirectly the one or more driving levers (3, 3a, 3b) into engagement with the piston rod (2).